Commit graph

1724 commits

Author SHA1 Message Date
Mitch Hayenga
df82a2d003 mem: Rework the structuring of the prefetchers
Re-organizes the prefetcher class structure. Previously the
BasePrefetcher forced multiple assumptions on the prefetchers that
inherited from it. This patch makes the BasePrefetcher class truly
representative of base functionality. For example, the base class no
longer enforces FIFO order. Instead, prefetchers with FIFO requests
(like the existing stride and tagged prefetchers) now inherit from a
new QueuedPrefetcher base class.

Finally, the stride-based prefetcher now assumes a custimizable lookup table
(sets/ways) rather than the previous fully associative structure.
2014-12-23 09:31:18 -05:00
Mitch Hayenga
6cb58b2bd2 mem: Add parameter to reserve MSHR entries for demand access
Adds a new parameter that reserves some number of MSHR entries for demand
accesses.  This helps prevent prefetchers from taking all MSHRs, forcing demand
requests from the CPU to stall.
2014-12-23 09:31:18 -05:00
Andreas Hansson
59460b91f3 config: Expose the DRAM ranks as a command-line option
This patch gives the user direct influence over the number of DRAM
ranks to make it easier to tune the memory density without affecting
the bandwidth (previously the only means of scaling the device count
was through the number of channels).

The patch also adds some basic sanity checks to ensure that the number
of ranks is a power of two (since we rely on bit slices in the address
decoding).
2014-12-23 09:31:18 -05:00
Andreas Hansson
2f7baf9dbe mem: Ensure DRAM controller is idle when in atomic mode
This patch addresses an issue seen with the KVM CPU where the refresh
events scheduled by the DRAM controller forces the simulator to switch
out of the KVM mode, thus killing performance.

The current patch works around the fact that we currently have no
proper API to inform a SimObject of the mode switches. Instead we rely
on drainResume being called after any switch, and cache the previous
mode locally to be able to decide on appropriate actions.

The switcheroo regression require a minor stats bump as a result.
2014-12-23 09:31:18 -05:00
Omar Naji
381d1da791 mem: Add rank-wise refresh to the DRAM controller
This patch adds rank-wise refresh to the controller, as opposed to the
channel-wide refresh currently in place. In essence each rank can be
refreshed independently, and for this to be possible the controller
is extended with a state machine per rank.

Without this patch the data bus is always idle during a refresh, as
all the ranks are refreshing at the same time. With the rank-wise
refresh it is possible to use one rank while another one is
refreshing, and thus the data bus can be kept busy.

The patch introduces a Rank class to encapsulate the state per rank,
and also shifts all the relevant banks, activation tracking etc to the
rank. The arbitration is also updated to consider the state of the rank.
2014-12-23 09:31:18 -05:00
Omar Naji
152c02354e mem: Fix a bug in the DRAM controller arbitration
Fix a minor issue that affects multi-rank systems.
2014-12-23 09:31:18 -05:00
Kanishk Sugand
7a25b1a0e0 mem: Add stack distance statistics to the CommMonitor
This patch adds the stack distance calculator to the CommMonitor. The
stats are disabled by default.
2014-12-23 09:31:18 -05:00
Kanishk Sugand
888975b29d mem: Add a stack distance calculator
This patch adds a stand-alone stack distance calculator. The stack
distance calculator is a passive SimObject that observes the addresses
passed to it. It calculates stack distances (LRU Distances) of
incoming addresses based on the partial sum hierarchy tree algorithm
described by Alamasi et al. http://doi.acm.org/10.1145/773039.773043.

For each transaction a hashtable look-up is performed. At every
non-unique transaction the tree is traversed from the leaf at the
returned index to the root, the old node is deleted from the tree, and
the sums (to the right) are collected and decremented. The collected
sum represets the stack distance of the found node. At every unique
transaction the stack distance is returned as
numeric_limits<uint64>::max().

In addition to the basic stack distance calculation, a feature to mark
an old node in the tree is added. This is useful if it is required to
see the reuse pattern. For example, Writebacks to the lower level
(e.g. membus from L2), can be marked instead of being removed from the
stack (isMarked flag of Node set to True). And then later if this same
address is accessed (by L1), the value of the isMarked flag would be
True. This gives some insight on how the Writeback policy of the
lower level affect the read/write accesses in an application.

Debugging is enabled by setting the verify flag to true. Debugging is
implemented using a dummy stack that behaves in a naive way, using STL
vectors. Note that this has a large impact on run time.
2014-12-23 09:31:18 -05:00
Marco Elver
dd0f3943e2 mem: Add MemChecker and MemCheckerMonitor
This patch adds the MemChecker and MemCheckerMonitor classes. While
MemChecker can be integrated anywhere in the system and is independent,
the most convenient usage is through the MemCheckerMonitor -- this
however, puts limitations on where the MemChecker is able to observe
read/write transactions.
2014-12-23 09:31:17 -05:00
Curtis Dunham
5d22250845 mem: Support WriteInvalidate (again)
This patch takes a clean-slate approach to providing WriteInvalidate
(write streaming, full cache line writes without first reading)
support.

Unlike the prior attempt, which took an aggressive approach of directly
writing into the cache before handling the coherence actions, this
approach follows the existing cache flows as closely as possible.
2014-12-02 06:08:19 -05:00
Curtis Dunham
7ca27dd3cc mem: Remove WriteInvalidate support
Prepare for a different implementation following in the next patch
2014-12-02 06:08:17 -05:00
Andreas Hansson
5c84157c29 mem: Relax packet src/dest check and shift onus to crossbar
This patch allows objects to get the src/dest of a packet even if it
is not set to a valid port id. This simplifies (ab)using the bridge as
a buffer and latency adapter in situations where the neighbouring
MemObjects are not crossbars.

The checks that were done in the packet are now shifted to the
crossbar where the fields are used to index into the port
arrays. Thus, the carrier of the information is not burdened with
checking, and the crossbar can check not only that the destination is
set, but also that the port index is within limits.
2014-12-02 06:07:56 -05:00
Andreas Hansson
ea5ccc7041 mem: Clean up packet data allocation
This patch attempts to make the rules for data allocation in the
packet explicit, understandable, and easy to verify. The constructor
that copies a packet is extended with an additional flag "alloc_data"
to enable the call site to explicitly say whether the newly created
packet is short-lived (a zero-time snoop), or has an unknown life-time
and therefore should allocate its own data (or copy a static pointer
in the case of static data).

The tricky case is the static data. In essence this is a
copy-avoidance scheme where the original source of the request (DMA,
CPU etc) does not ask the memory system to return data as part of the
packet, but instead provides a pointer, and then the memory system
carries this pointer around, and copies the appropriate data to the
location itself. Thus any derived packet actually never copies any
data. As the original source does not copy any data from the response
packet when arriving back at the source, we must maintain the copy of
the original pointer to not break the system. We might want to revisit
this one day and pay the price for a few extra memcpy invocations.

All in all this patch should make it easier to grok what is going on
in the memory system and how data is actually copied (or not).
2014-12-02 06:07:54 -05:00
Andreas Hansson
f012166bb6 mem: Cleanup Packet::checkFunctional and hasData usage
This patch cleans up the use of hasData and checkFunctional in the
packet. The hasData function is unfortunately suggesting that it
checks if the packet has a valid data pointer, when it does in fact
only check if the specific packet type is specified to have a data
payload. The confusion led to a bug in checkFunctional. The latter
function is also tidied up to avoid name overloading.
2014-12-02 06:07:52 -05:00
Andreas Hansson
a2ee51f631 mem: Make the requests carried by packets const
This adds a basic level of sanity checking to the packet by ensuring
that a request is not modified once the packet is created. The only
issue that had to be worked around is the relaying of
software-prefetches in the cache. The specific situation is now solved
by first copying the request, and then creating a new packet
accordingly.
2014-12-02 06:07:50 -05:00
Andreas Hansson
fa60d5cf27 mem: Make Request getters const
This patch tidies up the Request class, making all getters const. The
odd one out is incAccessDepth which is called by the memory system as
packets carry the request around. This is also const to enable the
packet to hold on to a const Request.
2014-12-02 06:07:48 -05:00
Andreas Hansson
3d6ec81e66 mem: Add checks and explanation for assertMemInhibit usage 2014-12-02 06:07:46 -05:00
Andreas Hansson
41846cb61b mem: Assume all dynamic packet data is array allocated
This patch simplifies how we deal with dynamically allocated data in
the packet, always assuming that it is array allocated, and hence
should be array deallocated (delete[] as opposed to delete). The only
uses of dataDynamic was in the Ruby testers.

The ARRAY_DATA flag in the packet is removed accordingly. No
defragmentation of the flags is done at this point, leaving a gap in
the bit masks.

As the last part the patch, it renames dataDynamicArray to dataDynamic.
2014-12-02 06:07:43 -05:00
Andreas Hansson
5df96cb690 mem: Remove redundant Packet::allocate calls
This patch cleans up the packet memory allocation confusion. The data
is always allocated at the requesting side, when a packet is created
(or copied), and there is never a need for any device to allocate any
space if it is merely responding to a paket. This behaviour is in line
with how SystemC and TLM works as well, thus increasing
interoperability, and matching established conventions.

The redundant calls to Packet::allocate are removed, and the checks in
the function are tightened up to make sure data is only ever allocated
once. There are still some oddities in the packet copy constructor
where we copy the data pointer if it is static (without ownership),
and allocate new space if the data is dynamic (with ownership). The
latter is being worked on further in a follow-on patch.
2014-12-02 06:07:41 -05:00
Andreas Hansson
0706a25203 mem: Use const pointers for port proxy write functions
This patch changes the various write functions in the port proxies
to use const pointers for all sources (similar to how memcpy works).

The one unfortunate aspect is the need for a const_cast in the packet,
to avoid having to juggle a const and a non-const data pointer. This
design decision can always be re-evaluated at a later stage.
2014-12-02 06:07:38 -05:00
Andreas Hansson
9779ba2e37 mem: Add const getters for write packet data
This patch takes a first step in tightening up how we use the data
pointer in write packets. A const getter is added for the pointer
itself (getConstPtr), and a number of member functions are also made
const accordingly. In a range of places throughout the memory system
the new member is used.

The patch also removes the unused isReadWrite function.
2014-12-02 06:07:36 -05:00
Andreas Hansson
25bfc24999 mem: Remove null-check bypassing in Packet::getPtr
This patch removes the parameter that enables bypassing the null check
in the Packet::getPtr method. A number of call sites assume the value
to be non-null.

The one odd case is the RubyTester, which issues zero-sized
prefetches(!), and despite being reads they had no valid data
pointer. This is now fixed, but the size oddity remains (unless anyone
object or has any good suggestions).

Finally, in the Ruby Sequencer, appropriate checks are made for flush
packets as they have no valid data pointer.
2014-12-02 06:07:34 -05:00
Omar Naji
0e63d2cd62 mem: Add a GDDR5 DRAM config
This patch adds a first cut GDDR5 config to accommodate the users
combining gem5 and GPUSim. The config is based on a SK Hynix
datasheet, and the Nvidia GTX580 specification. Someone from the
GPUSim user-camp should tweak the default page-policy and static
frontend and backend latencies.
2014-12-02 06:07:32 -05:00
Andreas Hansson
d66b14ca61 misc: Another round of static analysis fixups
Mostly addressing uninitialised members.
2014-11-24 09:03:38 -05:00
Alexandru Dutu
1f539f13c3 mem: Page Table map api modification
This patch adds uncacheable/cacheable and read-only/read-write attributes to
the map method of PageTableBase. It also modifies the constructor of TlbEntry
structs for all architectures to consider the new attributes.
2014-11-23 18:01:09 -08:00
Alexandru Dutu
c11bcb8119 mem: Multi Level Page Table bug fix
The multi level page table was giving false positives for already mapped
translations. This patch fixes the bogus behavior.
2014-11-23 18:01:09 -08:00
Alexandru Dutu
e4859fae5b mem: Page Table long lines
Trimmed down all the lines greater than 78 characters.
2014-11-23 18:01:09 -08:00
Andreas Hansson
9ffe0e7ba6 mem: Clarify unit of DRAM controller buffer size 2014-11-14 03:53:48 -05:00
Mitch Hayenga
9d6d8e02aa mem: Delete unused variable in Garnet NetworkLink
With recent changes OSX clang compilation fails due to an unused variable.
2014-11-12 09:05:23 -05:00
Nilay Vaish
0811f21f67 ruby: provide a backing store
Ruby's functional accesses are not guaranteed to succeed as of now.  While
this is not a problem for the protocols that are currently in the mainline
repo, it seems that coherence protocols for gpus rely on a backing store to
supply the correct data.  The aim of this patch is to make this backing store
configurable i.e. it comes into play only when a particular option:
--access-backing-store is invoked.

The backing store has been there since M5 and GEMS were integrated.  The only
difference is that earlier the system used to maintain the backing store and
ruby's copy was write-only.  Sometime last year, we moved to data being
supplied supplied by ruby in SE mode simulations.  And now we have patches on
the reviewboard, which remove ruby's copy of memory altogether and rely
completely on the system's memory to supply data.  This patch adds back a
SimpleMemory member to RubySystem.  This member is used only if the option:
access-backing-store is set to true.  By default, the memory would not be
accessed.
2014-11-06 05:42:21 -06:00
Nilay Vaish
3022d463fb ruby: interface with classic memory controller
This patch is the final in the series.  The whole series and this patch in
particular were written with the aim of interfacing ruby's directory controller
with the memory controller in the classic memory system.  This is being done
since ruby's memory controller has not being kept up to date with the changes
going on in DRAMs.  Classic's memory controller is more up to date and
supports multiple different types of DRAM.  This also brings classic and
ruby ever more close.  The patch also changes ruby's memory controller to
expose the same interface.
2014-11-06 05:42:21 -06:00
Nilay Vaish
68ddfab8a4 ruby: remove the function functionalReadBuffers()
This function was added when I had incorrectly arrived at the conclusion
that such a function can improve the chances of a functional read succeeding.
As was later realized, this is not possible in the current setup.  While the
code using this function was dropped long back, this function was not.  Hence
the patch.
2014-11-06 05:42:20 -06:00
Nilay Vaish
d25b722e4a ruby: coherence protocols: remove data block from dirctory entry
This patch removes the data block present in the directory entry structure
of each protocol in gem5's mainline.  Firstly, this is required for moving
towards common set of memory controllers for classic and ruby memory systems.
Secondly, the data block was being misused in several places.  It was being
used for having free access to the physical memory instead of calling on the
memory controller.

From now on, the directory controller will not have a direct visibility into
the physical memory.  The Memory Vector object now resides in the
Memory Controller class.  This also means that some significant changes are
being made to the functional accesses in ruby.
2014-11-06 05:42:20 -06:00
Nilay Vaish
0baaed60ab ruby: slicc: allow adding a bool to an int, like C++. 2014-11-06 05:42:20 -06:00
Nilay Vaish
85c29973a3 ruby: remove sparse memory.
In my opinion, it creates needless complications in rest of the code.
Also, this structure hinders the move towards common set of code for
physical memory controllers.
2014-11-06 05:42:20 -06:00
Nilay Vaish
95a0b18431 ruby: single physical memory in fs mode
Both ruby and the system used to maintain memory copies.  With the changes
carried for programmed io accesses, only one single memory is required for
fs simulations.  This patch sets the copy of memory that used to reside
with the system to null, so that no space is allocated, but address checks
can still be carried out.  All the memory accesses now source and sink values
to the memory maintained by ruby.
2014-11-06 05:41:44 -06:00
Nilay Vaish
8ccfd9defa ruby: dma sequencer: remove RubyPort as parent class
As of now DMASequencer inherits from the RubyPort class.  But the code in
RubyPort class is heavily tailored for the CPU Sequencer.  There are parts of
the code that are not required at all for the DMA sequencer.  Moreover, the
next patch uses the dma sequencer for carrying out memory accesses for all the
io devices.  Hence, it is better to have a leaner dma sequencer.
2014-11-06 00:55:09 -06:00
Ali Saidi
b31d9e93e2 arm, mem: Fix drain bug and provide drain prints for more components. 2014-10-29 23:18:26 -05:00
Curtis Dunham
4024fab7fc mem: don't inhibit WriteInv's or defer snoops on their MSHRs
WriteInvalidate semantics depend on the unconditional writeback
or they won't complete.  Also, there's no point in deferring snoops
on their MSHRs, as they don't get new data at the end of their life
cycle the way other transactions do.

Add comment in the cache about a minor inefficiency re: WriteInvalidate.
2014-10-21 17:04:41 -05:00
Curtis Dunham
46f9f11a55 mem: have WriteInvalidate obsolete MSHRs
Since WriteInvalidate directly writes into the cache, it can
create tricky timing interleavings with reads and writes to the
same cache line that haven't yet completed.  This patch ensures
that these requests, when completed, don't overwrite the newer
data from the WriteInvalidate.
2014-10-29 23:18:24 -05:00
Omar Naji
a4a8568bd2 mem: Fix DRAM activationlLimit bug
Ensure that we do the proper event scheduling also when the activation
limit is disabled.
2014-10-20 18:03:55 -04:00
Omar Naji
29dd2887f4 mem: Add DRAM device size and check against config
This patch adds the size of the DRAM device to the DRAM config. It
also compares the actual DRAM size (calculated using information from
the config) to the size defined in the system. If these two values do
not match gem5 will print a warning. In order to do correct DRAM
research the size of the memory defined in the system should match the
size of the DRAM in the config. The timing and current parameters
found in the DRAM configs are defined for a DRAM device with a
specific size and would differ for another device with a different
size.
2014-10-20 18:03:52 -04:00
Andreas Hansson
6d4866383f mem: Modernise PhysicalMemory with C++11 features
Bring the PhysicalMemory up-to-date by making use of range-based for
loops and vector intialisation where possible.
2014-10-16 05:50:01 -04:00
Andreas Hansson
edc77fc03c misc: Move AddrRangeList from port.hh to addr_range.hh
The new location seems like a better fit. The iterator typedefs are
removed in favour of using C++11 auto.
2014-10-16 05:49:59 -04:00
Andrew Bardsley
d6732895a5 mem: Add ExternalMaster and ExternalSlave ports
This patch adds two MemoryObject's: ExternalMaster and ExternalSlave.
Each object has a single port which can be bound to an externally-
provided bridge to a port of another simulation system at
initialisation.
2014-10-16 05:49:56 -04:00
Andreas Hansson
db3739682d mem: Use shared_ptr for Ruby Message classes
This patch transitions the Ruby Message and its derived classes from
the ad-hoc RefCountingPtr to the c++11 shared_ptr. There are no
changes in behaviour, and the code modifications are mainly replacing
"new" with "make_shared".

The cloning of derived messages is slightly changed as they previously
relied on overriding the base-class through covariant return types.
2014-10-16 05:49:49 -04:00
Andreas Hansson
2475862747 arch,x86,mem: Dynamically determine the ISA for Ruby store check
This patch makes the memory system ISA-agnostic by enabling the Ruby
Sequencer to dynamically determine if it has to do a store check. To
enable this check, the ISA is encoded as an enum, and the system
is able to provide the ISA to the Sequencer at run time.

--HG--
rename : src/arch/x86/insts/microldstop.hh => src/arch/x86/ldstflags.hh
2014-10-16 05:49:44 -04:00
Andreas Hansson
df973abef3 mem: Dynamically determine page bytes in memory components
This patch takes a step towards an ISA-agnostic memory
system by enabling the components to establish the page size after
instantiation. The swap operation in the memory is now also allowing
any granularity to avoid depending on the IntReg of the ISA.
2014-10-16 05:49:43 -04:00
Nilay Vaish
a098fad174 ruby: network: garnet: add statistics for different activities
This patch adds some statistics to garnet that record the activity
of certain structures in the on-chip network.  These statistics, in a later
patch, will be used for computing the energy consumed by the on-chip network.
2014-10-11 15:02:23 -05:00
Nilay Vaish
25bb18f12b ruby: network: garnet: remove functions for computing power 2014-10-11 15:02:23 -05:00
Nilay Vaish
9321a41c62 ruby: drop Orion network power model
Orion is being dropped from ruby.  It would be replaced with DSENT
which has better models.  Note that the power / energy numbers reported
after this patch has been applied are not for use.
2014-10-11 15:02:23 -05:00
Nilay Vaish
b6d804a1e6 ruby: mesi: slight renaming 2014-10-11 15:02:23 -05:00
Nilay Vaish
e7f918d8cd ruby: structures: coorect #ifndef macros in header files 2014-10-11 15:02:22 -05:00
Omar Naji
cd8023a1ee mem: DRAMPower integration for on-line DRAM power stats
This patch takes the final step in integrating DRAMPower and adds the
appropriate calls in the DRAM controller to provide the command trace
and extract the power and energy stats. The debug printouts are still
left in place, but will eventually be removed.

At the moment the DRAM power calculation is always on when using the
DRAM controller model. The run-time impact of this addition is around
1.5% when looking at the total host seconds of the regressions. We
deem this a sensible trade-off to avoid the complication of adding an
enable/disable mechanism.
2014-07-29 17:22:44 +01:00
Omar Naji
afc6ce6228 mem: Add DRAMPower wrapping class
This patch adds a class to wrap DRAMPower Library in gem5.
This class initiates an object of class MemorySpecification
of the DRAMPower Library, passes the parameters from DRAMCtrl.py
to this object and creates an object of drampower library using
the memory specification.
2014-07-29 17:29:36 +01:00
Omar Naji
00b37ffe50 mem: Add missig timing and current parameters to DRAM configs
This patch adds missing timing and current parameters to the existing
DRAM configs. These missing timing and current parameters are required
by DRAMPower for the DRAM power calculations. The missing values are
datasheet values of the specified DRAMs, and the appropriate
references are added for the variuos configs.
2014-07-25 10:05:59 +01:00
Omar Naji
f9fce9ba07 mem: Remove DRAMSim2 DDR3 configuration
This patch prunes the DDR3 config that was initially created to match
the default config of DRAMSim2. The config is not complete as it is,
and to avoid having to maintain it, the easiest way forward is to
simply prune it. Going forward we are adding power number etc to the
other configurations.
2014-10-09 17:52:04 -04:00
Andreas Hansson
f4a538f862 mem: Add packet sanity checks to cache and MSHRs
This patch adds a number of asserts to the cache, checking basic
assumptions about packets being requests or responses.
2014-10-09 17:51:56 -04:00
Andreas Hansson
4a453e8c95 mem: Allow packet queue to move next send event forward
This patch changes the packet queue such that when scheduling a send,
the queue is allowed to move the event forward.
2014-10-09 17:51:52 -04:00
Andreas Hansson
6498ccddb2 misc: Fix issues identified by static analysis
Another bunch of issues addressed.
2014-10-01 08:05:54 -04:00
Curtis Dunham
b7f1d675da mem: Output precise range when XBar has conflicts 2014-09-27 09:08:32 -04:00
Curtis Dunham
725be98fe8 mem: Provide better diagnostic for unconnected port
When _masterPort is null, a message to that effect is
more helpful than a segfault.
2014-09-27 09:08:30 -04:00
Andreas Hansson
de62aedabc misc: Fix a bunch of minor issues identified by static analysis
Add some missing initialisation, and fix a handful benign resource
leaks (including some false positives).
2014-09-27 09:08:29 -04:00
Andreas Hansson
1f6d5f8f84 mem: Rename Bus to XBar to better reflect its behaviour
This patch changes the name of the Bus classes to XBar to better
reflect the actual timing behaviour. The actual instances in the
config scripts are not renamed, and remain as e.g. iobus or membus.

As part of this renaming, the code has also been clean up slightly,
making use of range-based for loops and tidying up some comments. The
only changes outside the bus/crossbar code is due to the delay
variables in the packet.

--HG--
rename : src/mem/Bus.py => src/mem/XBar.py
rename : src/mem/coherent_bus.cc => src/mem/coherent_xbar.cc
rename : src/mem/coherent_bus.hh => src/mem/coherent_xbar.hh
rename : src/mem/noncoherent_bus.cc => src/mem/noncoherent_xbar.cc
rename : src/mem/noncoherent_bus.hh => src/mem/noncoherent_xbar.hh
rename : src/mem/bus.cc => src/mem/xbar.cc
rename : src/mem/bus.hh => src/mem/xbar.hh
2014-09-20 17:18:32 -04:00
Stephan Diestelhorst
435f4aec3d mem: Add access statistics for the snoop filter
Adds a simple access counter for requests and snoops for the snoop filter and
also classifies hits based on whether a single other holder existed or whether
multiple shares held the line.
2014-04-25 12:36:16 +01:00
Stephan Diestelhorst
afa2428eca mem: Tie in the snoop filter in the coherent bus 2014-09-20 17:18:29 -04:00
Stephan Diestelhorst
7d488cc66f mem: Add a simple snoop counter per bus
This patch adds a simple counter for both total messages and a histogram for
the fan-out of snoop messages.  The fan-out describes to how many ports snoops
had to be sent per incoming request / snoop-from-below.  Without any
cleverness, this usually means to either all, or all but the requesting port.
2014-04-24 13:28:47 +01:00
Stephan Diestelhorst
ba98d598ae mem: Simple Snoop Filter
This is a first cut at a simple snoop filter that tracks presence of lines in
the caches "above" it. The snoop filter can be applied at any given cache
hierarchy and will then handle the caches above it appropriately; there is no
need to use this only in the last-level bus.

This design currently has some limitations: missing stats, no notion of clean
evictions (these will not update the underlying snoop filter, because they are
not sent from the evicting cache down), no notion of capacity for the snoop
filter and thus no need for invalidations caused by capacity pressure in the
snoop filter. These are planned to be added on top with future change sets.
2014-09-20 17:18:26 -04:00
Wendy Elsasser
bf23847072 mem: Add DDR4 bank group timing
Added the following parameter to the DRAMCtrl class:
 - bank_groups_per_rank

This defaults to 1. For the DDR4 case, the default is overridden to indicate
bank group architecture, with multiple bank groups per rank.

Added the following delays to the DRAMCtrl class:
 - tCCD_L : CAS-to-CAS, same bank group delay
 - tRRD_L : RAS-to-RAS, same bank group delay

These parameters are only applied when bank group timing is enabled.  Bank
group timing is currently enabled only for DDR4 memories.

For all other memories, these delays will default to '0 ns'

In the DRAM controller model, applied the bank group timing to the per bank
parameters actAllowedAt and colAllowedAt.
The actAllowedAt will be updated based on bank group when an ACT is issued.
The colAllowedAt will be updated based on bank group when a RD/WR burst is
issued.

At the moment no modifications are made to the scheduling.
2014-09-20 17:18:21 -04:00
Wendy Elsasser
b6ecfe9183 mem: Add memory rank-to-rank delay
Add the following delay to the DRAM controller:
 - tCS : Different rank bus turnaround delay

This will be applied for
 1) read-to-read,
 2) write-to-write,
 3) write-to-read, and
 4) read-to-write
command sequences, where the new command accesses a different rank
than the previous burst.

The delay defaults to 2*tCK for each defined memory class. Note that
this does not correspond to one particular timing constraint, but is a
way of modelling all the associated constraints.

The DRAM controller has some minor changes to prioritize commands to
the same rank. This prioritization will only occur when the command
stream is not switching from a read to write or vice versa (in the
case of switching we have a gap in any case).

To prioritize commands to the same rank, the model will determine if there are
any commands queued (same type) to the same rank as the previous command.
This check will ensure that the 'same rank' command will be able to execute
without adding bubbles to the command flow, e.g. any ACT delay requirements
can be done under the hoods, allowing the burst to issue seamlessly.
2014-09-20 17:17:57 -04:00
Mitch Hayenga
3e5bf0c922 mem: Remove the GHB prefetcher from the source tree
There are two primary issues with this code which make it deserving of deletion.

1) GHB is a way to structure a prefetcher, not a definitive type of prefetcher
2) This prefetcher isn't even structured like a GHB prefetcher.
   It's basically a worse version of the stride prefetcher.

It primarily serves to confuse new gem5 users and most functionality is already
present in the stride prefetcher.
2014-09-20 17:17:44 -04:00
Andreas Hansson
efd5cf323a misc: Use safe_cast when assumptions are made about return value
This patch changes two dynamic_cast to safe_cast as we assume the
return value is not NULL (without checking).
2014-09-19 10:35:11 -04:00
Andreas Hansson
f615c4aeb0 misc: Remove assertions ensuring unsigned values >= 0 2014-09-19 10:35:07 -04:00
Andreas Hansson
377f081251 mem: Check return value of checkFunctional in SimpleMemory
Simple fix to ensure we only iterate until we are done.
2014-09-19 10:35:06 -04:00
Andreas Hansson
38646d48eb mem: Add checks to sendTimingReq in cache
A small fix to ensure the return value is not ignored.
2014-09-19 10:35:04 -04:00
Nilay Vaish
2ccdfc547d ruby: network: revert some of the changes from ad9c042dce54
The changeset ad9c042dce54 made changes to the structures under the network
directory to use a map of buffers instead of vector of buffers.
The reasoning was that not all vnets that are created are used and we
needlessly allocate more buffers than required and then iterate over them
while processing network messages.  But the move to map resulted in a slow
down which was pointed out by Andreas Hansson.  This patch moves things
back to using vector of message buffers.
2014-09-15 16:19:38 -05:00
Mitch Hayenga
9a595fac74 mem: Add accessor function for vaddr
Determine if a request has an associated virtual address.
2014-09-09 04:36:33 -04:00
Andreas Hansson
da4539dc74 misc: Fix a number of unitialised variables and members
Static analysis unearther a bunch of uninitialised variables and
members, and this patch addresses the problem. In all cases these
omissions seem benign in the end, but at least fixing them means less
false positives next time round.
2014-09-09 04:36:31 -04:00
Andreas Hansson
2698e73966 base: Use the global Mersenne twister throughout
This patch tidies up random number generation to ensure that it is
done consistently throughout the code base. In essence this involves a
clean-up of Ruby, and some code simplifications in the traffic
generator.

As part of this patch a bunch of skewed distributions (off-by-one etc)
have been fixed.

Note that a single global random number generator is used, and that
the object instantiation order will impact the behaviour (the sequence
of numbers will be unaffected, but if module A calles random before
module B then they would obviously see a different outcome). The
dependency on the instantiation order is true in any case due to the
execution-model of gem5, so we leave it as is. Also note that the
global ranom generator is not thread safe at this point.

Regressions using the memtest, TrafficGen or any Ruby tester are
affected and will be updated accordingly.
2014-09-03 07:42:54 -04:00
Andreas Hansson
1ff4c45bbb mem: Avoid unecessary retries when bus peer is not ready
This patch removes unecessary retries that happened when the bus layer
itself was no longer busy, but the the peer was not yet ready. Instead
of sending a retry that will inevitably not succeed, the bus now
silenty waits until the peer sends a retry.
2014-09-03 07:42:53 -04:00
Curtis Dunham
f6f63ec0aa mem: write streaming support via WriteInvalidate promotion
Support full-block writes directly rather than requiring RMW:
 * a cache line is allocated in the cache upon receipt of a
   WriteInvalidateReq, not the WriteInvalidateResp.
 * only top-level caches allocate the line; the others just pass
   the request along and invalidate as necessary.
 * to close a timing window between the *Req and the *Resp, a new
   metadata bit tracks whether another cache has read a copy of
   the new line before the writeback to memory.
2014-06-27 12:29:00 -05:00
Andreas Hansson
3be4f4b846 mem: Fix a bug in the cache port flow control
This patch fixes a bug in the cache port where the retry flag was
reset too early, allowing new requests to arrive before the retry was
actually sent, but with the event already scheduled. This caused a
deadlock in the interactions with the O3 LSQ.

The patche fixes the underlying issue by shifting the resetting of the
flag to be done by the event that also calls sendRetry(). The patch
also tidies up the flow control in recvTimingReq and ensures that we
also check if we already have a retry outstanding.
2014-09-03 07:42:50 -04:00
Curtis Dunham
5d029463ee cpu, mem: Make software prefetches non-blocking
Previously, they were treated so much like loads that they could stall
at the head of the ROB.  Now they are always treated like L1 hits.
If they actually miss, a new request is created at the L1 and tracked
from the MSHRs there if necessary (i.e. if it didn't coalesce with
an existing outstanding load).
2014-05-13 12:20:49 -05:00
Curtis Dunham
e3b19cb294 mem: Refactor assignment of Packet types
Put the packet type swizzling (that is currently done in a lot of places)
into a refineCommand() member function.
2014-05-13 12:20:48 -05:00
Geoffrey Blake
b404ffde60 cache: Fix handling of LL/SC requests under contention
If a set of LL/SC requests contend on the same cache block we
can get into a situation where CPUs will deadlock if they expect
a failed SC to supply them data.  This case happens where 3 or
more cores are contending for a cache block using LL/SC and the system
is configured where 2 cores are connected to a local bus and the
third is connected to a remote bus.  If a core on the local bus
sends an SCUpgrade and the core on the remote bus sends and SCUpgrade
they will race to see who will win the SC access.  In the meantime
if the other core appends a read to one of the SCUpgrades it will expect
to be supplied data by that SCUpgrade transaction.  If it happens that
the SCUpgrade that was picked to supply the data is failed, it will
drop the appended request for data and never respond, leaving the requesting
core to deadlock.  This patch makes all SC's behave as normal stores to
prevent this case but still makes sure to check whether it can perform
the update.
2014-09-03 07:42:31 -04:00
Andreas Hansson
77c28cc395 mem: Packet queue clean up
No change in functionality, just a bit of tidying up.
2014-09-03 07:42:28 -04:00
Andreas Hansson
e1ac962939 arch: Cleanup unused ISA traits constants
This patch prunes unused values, and also unifies how the values are
defined (not using an enum for ALPHA), aligning the use of int vs Addr
etc.

The patch also removes the duplication of PageBytes/PageShift and
VMPageSize/LogVMPageSize. For all ISAs the two pairs had identical
values and the latter has been removed.
2014-09-03 07:42:21 -04:00
Nilay Vaish
2cbe7c705b ruby: remove typedef of Index as int64
The Index type defined as typedef int64 does not really provide any help
since in most places we use primitive types instead of Index.  Also, the name
Index is very generic that it does not merit being used as a typename.
2014-09-01 16:55:50 -05:00
Nilay Vaish
b4dade6fb2 ruby: PerfectSwitch: moves code to a per vnet helper function
This patch moves code from the wakeup() function to a operateVnet().
The aim is to improve the readiblity of the code.
2014-09-01 16:55:48 -05:00
Nilay Vaish
7a0d5aafe4 ruby: message buffers: significant changes
This patch is the final patch in a series of patches.  The aim of the series
is to make ruby more configurable than it was.  More specifically, the
connections between controllers are not at all possible (unless one is ready
to make significant changes to the coherence protocol).  Moreover the buffers
themselves are magically connected to the network inside the slicc code.
These connections are not part of the configuration file.

This patch makes changes so that these connections will now be made in the
python configuration files associated with the protocols.  This requires
each state machine to expose the message buffers it uses for input and output.
So, the patch makes these buffers configurable members of the machines.

The patch drops the slicc code that usd to connect these buffers to the
network.  Now these buffers are exposed to the python configuration system
as Master and Slave ports.  In the configuration files, any master port
can be connected any slave port.  The file pyobject.cc has been modified to
take care of allocating the actual message buffer.  This is inline with how
other port connections work.
2014-09-01 16:55:47 -05:00
Nilay Vaish
00286fc5cb build opts: add MI_example to NULL ISA
A later changeset changes the file src/python/swig/pyobject.cc to include
a header file that includes a header file generated at build time depending
on the PROTOCOL in use.  Since NULL ISA was not specifying any protocol,
this resulted in compilation problems.  Hence, the changeset.
2014-09-01 16:55:46 -05:00
Nilay Vaish
d07abd9b5b mem: change the namespace Message to ProtoMessage
The namespace Message conflicts with the Message data type used extensively
in Ruby.  Since Ruby is being moved to the same Master/Slave ports based
configuration style as the rest of gem5, this conflict needs to be resolved.
Hence, the namespace is being renamed to ProtoMessage.
2014-09-01 16:55:46 -05:00
Nilay Vaish
cee8faaad0 ruby: slicc: change the way configurable members are specified
There are two changes this patch makes to the way configurable members of a
state machine are specified in SLICC.  The first change is that the data
member declarations will need to be separated by a semi-colon instead of a
comma.  Secondly, the default value to be assigned would now use SLICC's
assignment operator i.e. ':='.
2014-09-01 16:55:45 -05:00
Nilay Vaish
b1d3873ec5 ruby: slicc: improve the grammar
This patch changes the grammar for SLICC so as to remove some of the
redundant / duplicate rules.  In particular rules for object/variable
declaration and class member declaration have been unified. Similarly, the
rules for a general function and a class method have been unified.

One more change is in the priority of two rules.  The first rule is on
declaring a function with all the params typed and named.  The second rule is
on declaring a function with all the params only typed.  Earlier the second
rule had a higher priority.  Now the first rule has a higher priority.
2014-09-01 16:55:44 -05:00
Nilay Vaish
3202ec98e7 ruby: mesi three level: slight naming changes. 2014-09-01 16:55:44 -05:00
Nilay Vaish
557200725c ruby: slicc: donot prefix machine name to variables
This changeset does away with prefixing of member variables of state machines
with the identity of the machine itself.
2014-09-01 16:55:43 -05:00
Nilay Vaish
6ceb1aadc2 ruby: remove unused toString() from AbstractController 2014-09-01 16:55:42 -05:00
Nilay Vaish
00dbadcbb0 ruby: network: move getNumNodes() to base class
All the implementations were doing the same things.
2014-09-01 16:55:42 -05:00
Nilay Vaish
cc2cc58869 ruby: eliminate type Time
There is another type Time in src/base class which results in a conflict.
2014-09-01 16:55:41 -05:00
Nilay Vaish
82d136285d ruby: move files from ruby/system to ruby/structures
The directory ruby/system is crowded and unorganized. Hence, the files the
hold actual physical structures, are being moved to the directory
ruby/structures.  This includes Cache Memory, Directory Memory,
Memory Controller, Wire Buffer, TBE Table, Perfect Cache Memory, Timer Table,
Bank Array.

The directory ruby/systems has the glue code that holds these structures
together.

--HG--
rename : src/mem/ruby/system/MachineID.hh => src/mem/ruby/common/MachineID.hh
rename : src/mem/ruby/buffers/MessageBuffer.cc => src/mem/ruby/network/MessageBuffer.cc
rename : src/mem/ruby/buffers/MessageBuffer.hh => src/mem/ruby/network/MessageBuffer.hh
rename : src/mem/ruby/buffers/MessageBufferNode.cc => src/mem/ruby/network/MessageBufferNode.cc
rename : src/mem/ruby/buffers/MessageBufferNode.hh => src/mem/ruby/network/MessageBufferNode.hh
rename : src/mem/ruby/system/AbstractReplacementPolicy.hh => src/mem/ruby/structures/AbstractReplacementPolicy.hh
rename : src/mem/ruby/system/BankedArray.cc => src/mem/ruby/structures/BankedArray.cc
rename : src/mem/ruby/system/BankedArray.hh => src/mem/ruby/structures/BankedArray.hh
rename : src/mem/ruby/system/Cache.py => src/mem/ruby/structures/Cache.py
rename : src/mem/ruby/system/CacheMemory.cc => src/mem/ruby/structures/CacheMemory.cc
rename : src/mem/ruby/system/CacheMemory.hh => src/mem/ruby/structures/CacheMemory.hh
rename : src/mem/ruby/system/DirectoryMemory.cc => src/mem/ruby/structures/DirectoryMemory.cc
rename : src/mem/ruby/system/DirectoryMemory.hh => src/mem/ruby/structures/DirectoryMemory.hh
rename : src/mem/ruby/system/DirectoryMemory.py => src/mem/ruby/structures/DirectoryMemory.py
rename : src/mem/ruby/system/LRUPolicy.hh => src/mem/ruby/structures/LRUPolicy.hh
rename : src/mem/ruby/system/MemoryControl.cc => src/mem/ruby/structures/MemoryControl.cc
rename : src/mem/ruby/system/MemoryControl.hh => src/mem/ruby/structures/MemoryControl.hh
rename : src/mem/ruby/system/MemoryControl.py => src/mem/ruby/structures/MemoryControl.py
rename : src/mem/ruby/system/MemoryNode.cc => src/mem/ruby/structures/MemoryNode.cc
rename : src/mem/ruby/system/MemoryNode.hh => src/mem/ruby/structures/MemoryNode.hh
rename : src/mem/ruby/system/MemoryVector.hh => src/mem/ruby/structures/MemoryVector.hh
rename : src/mem/ruby/system/PerfectCacheMemory.hh => src/mem/ruby/structures/PerfectCacheMemory.hh
rename : src/mem/ruby/system/PersistentTable.cc => src/mem/ruby/structures/PersistentTable.cc
rename : src/mem/ruby/system/PersistentTable.hh => src/mem/ruby/structures/PersistentTable.hh
rename : src/mem/ruby/system/PseudoLRUPolicy.hh => src/mem/ruby/structures/PseudoLRUPolicy.hh
rename : src/mem/ruby/system/RubyMemoryControl.cc => src/mem/ruby/structures/RubyMemoryControl.cc
rename : src/mem/ruby/system/RubyMemoryControl.hh => src/mem/ruby/structures/RubyMemoryControl.hh
rename : src/mem/ruby/system/RubyMemoryControl.py => src/mem/ruby/structures/RubyMemoryControl.py
rename : src/mem/ruby/system/SparseMemory.cc => src/mem/ruby/structures/SparseMemory.cc
rename : src/mem/ruby/system/SparseMemory.hh => src/mem/ruby/structures/SparseMemory.hh
rename : src/mem/ruby/system/TBETable.hh => src/mem/ruby/structures/TBETable.hh
rename : src/mem/ruby/system/TimerTable.cc => src/mem/ruby/structures/TimerTable.cc
rename : src/mem/ruby/system/TimerTable.hh => src/mem/ruby/structures/TimerTable.hh
rename : src/mem/ruby/system/WireBuffer.cc => src/mem/ruby/structures/WireBuffer.cc
rename : src/mem/ruby/system/WireBuffer.hh => src/mem/ruby/structures/WireBuffer.hh
rename : src/mem/ruby/system/WireBuffer.py => src/mem/ruby/structures/WireBuffer.py
rename : src/mem/ruby/recorder/CacheRecorder.cc => src/mem/ruby/system/CacheRecorder.cc
rename : src/mem/ruby/recorder/CacheRecorder.hh => src/mem/ruby/system/CacheRecorder.hh
2014-09-01 16:55:40 -05:00
Alexandru
5efbb4442a mem: adding architectural page table support for SE mode
This patch enables the use of page tables that are stored in system memory
and respect x86 specification, in SE mode. It defines an architectural
page table for x86 as a MultiLevelPageTable class and puts a placeholder
class for other ISAs page tables, giving the possibility for future
implementation.
2014-08-28 10:11:44 -05:00
Alexandru
26ac28dec2 mem: adding a multi-level page table class
This patch defines a multi-level page table class that stores the page table in
system memory, consistent with ISA specifications. In this way, cpu models that
use the actual hardware to execute (e.g. KvmCPU), are able to traverse the page
table.
2014-04-01 12:18:12 -05:00
Andreas Hansson
9e4cd5bf1e mem: Fix DRAMSim2 cycle check when restoring from checkpoint
This patch ensures the cycle check is still valid even restoring from
a checkpoint. In this case the DRAMSim2 cycle count is relative to the
startTick rather than 0.
2014-08-26 10:14:38 -04:00
Andreas Hansson
3efabb4b2f mem: Update DRAM controller comments
Update comments and add a reference for more information.
2014-08-26 10:13:03 -04:00
Andreas Hansson
56b7796e0d mem: Fix address interleaving bug in DRAM controller
This patch fixes a bug in the DRAM controller address decoding. In
cases where the DRAM burst size (e.g. 32 bytes in a rank with a single
LPDDR3 x32) was smaller than the channel interleaving size
(e.g. systems with a 64-byte cache line) one address bit effectively
got used as a channel bit when it should have been a low-order column
bit.

This patch adds a notion of "columns per stripe", and more clearly
deals with the low-order column bits and high-order column bits. The
patch also relaxes the granularity check such that it is possible to
use interleaving granularities other than the cache line size.

The patch also adds a missing M5_CLASS_VAR_USED to the tCK member as
it is only used in the debug build for now.
2014-08-26 10:12:45 -04:00
Mitch Hayenga
f6f6ae461e mem: Properly set cache block status fields on writebacks
When a cacheline is written back to a lower-level cache,
tags->insertBlock() sets various status parameters. However these
status bits were cleared immediately after calling. This patch makes
it so that these status fields are not cleared by moving them outside
of the tags->insertBlock() call.
2014-08-13 06:57:24 -04:00
Anthony Gutierrez
a628afedad mem: refactor LRU cache tags and add random replacement tags
this patch implements a new tags class that uses a random replacement policy.
these tags prefer to evict invalid blocks first, if none are available a
replacement candidate is chosen at random.

this patch factors out the common code in the LRU class and creates a new
abstract class: the BaseSetAssoc class. any set associative tag class must
implement the functionality related to the actual replacement policy in the
following methods:

accessBlock()
findVictim()
insertBlock()
invalidate()
2014-07-28 12:23:23 -04:00
Andreas Hansson
1f539ce4cc mem: DRAMPower trace output
This patch adds a DRAMPower flag to enable off-line DRAM power
analysis using the DRAMPower tool. A new DRAMPower flag is added
and a follow-on patch adds a Python script to post-process the output
and order it based on time stamps.

The long-term goal is to link DRAMPower as a library and provide the
commands through function calls to the model rather than first
printing and then parsing the commands. At the moment it is also up to
the user to ensure that the same DRAM configuration is used by the
gem5 controller model and DRAMPower.
2014-06-30 13:56:03 -04:00
Andreas Hansson
b4ce51eb9e mem: Add bank and rank indices as fields to the DRAM bank
This patch adds the index of the bank and rank as a field so that we can
determine the identity of a given bank (reference or pointer) for the
power tracing. We also grab the opportunity of cleaning up the
arguments used for identifying the bank when activating.
2014-06-30 13:56:02 -04:00
Andreas Hansson
d59bc8ee1f mem: Extend DRAM row bits from 16 to 32 for larger densities
This patch extends the DRAM row bits to 32 to support larger density
memories. Additional checks are also added to ensure the row fits in
the 32 bits.
2014-06-30 13:56:01 -04:00
Steve Reinhardt
0be64ffe2f style: eliminate equality tests with true and false
Using '== true' in a boolean expression is totally redundant,
and using '== false' is pretty verbose (and arguably less
readable in most cases) compared to '!'.

It's somewhat of a pet peeve, perhaps, but I had some time
waiting for some tests to run and decided to clean these up.

Unfortunately, SLICC appears not to have the '!' operator,
so I had to leave the '== false' tests in the SLICC code.
2014-05-31 18:00:23 -07:00
Nilay Vaish
e685767b58 ruby: slicc: remove unused ids DNUCA* 2014-05-23 06:07:02 -05:00
Nilay Vaish
9c9257a612 ruby: remove old protocol documentation 2014-05-23 06:07:02 -05:00
Nilay Vaish
8bf41e41c1 ruby: message buffer: drop dequeue_getDelayCycles()
The functionality of updating and returning the delay cycles would now be
performed by the dequeue() function itself.
2014-05-23 06:07:02 -05:00
Andreas Hansson
f800f268db mem: Update DDR3 and DDR4 based on datasheets
This patch makes a more firm connection between the DDR3-1600
configuration and the corresponding datasheet, and also adds a
DDR3-2133 and a DDR4-2400 configuration. At the moment there is also
an ongoing effort to align the choice of datasheets to what is
available in DRAMPower.
2014-05-09 18:58:49 -04:00
Andreas Hansson
cc4ca78f99 mem: Add DRAM cycle time
This patch extends the current timing parameters with the DRAM cycle
time. This is needed as the DRAMPower tool expects timestamps in DRAM
cycles. At the moment we could get away with doing this in a
post-processing step as the DRAMPower execution is separate from the
simulation run. However, in the long run we want the tool to be called
during the simulation, and then the cycle time is needed.
2014-05-09 18:58:49 -04:00
Andreas Hansson
8c56efe747 mem: Simplify DRAM response scheduling
This patch simplifies the DRAM response scheduling based on the
assumption that they are always returned in order.
2014-05-09 18:58:48 -04:00
Andreas Hansson
8e3869411d mem: Add precharge all (PREA) to the DRAM controller
This patch adds the basic ingredients for a precharge all operation,
to be used in conjunction with DRAM power modelling.

Currently we do not try and apply any cleverness when precharging all
banks, thus even if only a single bank is open we use PREA as opposed
to PRE. At the moment we only have a single tRP (tRPpb), and do not
model the slightly longer all-bank precharge constraint (tRPab).
2014-05-09 18:58:48 -04:00
Andreas Hansson
0ba1e72e9b mem: Remove printing of DRAM params
This patch removes the redundant printing of DRAM params.
2014-05-09 18:58:48 -04:00
Andreas Hansson
6753cb705e mem: Add tRTP to the DRAM controller
This patch adds the tRTP timing constraint, governing the minimum time
between a read command and a precharge. Default values are provided
for the existing DRAM types.
2014-05-09 18:58:48 -04:00
Andreas Hansson
60799dc552 mem: Merge DRAM latency calculation and bank state update
This patch merges the two control paths used to estimate the latency
and update the bank state. As a result of this merging the computation
is now in one place only, and should be easier to follow as it is all
done in absolute (rather than relative) time.

As part of this change, the scheduling is also refined to ensure that
we look at a sensible estimate of the bank ready time in choosing the
next request. The bank latency stat is removed as it ends up being
misleading when the DRAM access code gets evaluated ahead of time (due
to the eagerness of waking the model up for scheduling the next
request).
2014-05-09 18:58:48 -04:00
Andreas Hansson
b8631d9ae8 mem: Add tWR to DRAM activate and precharge constraints
This patch adds the write recovery time to the DRAM timing
constraints, and changes the current tRASDoneAt to a more generic
preAllowedAt, capturing when a precharge is allowed to take place.

The part of the DRAM access code that accounts for the precharge and
activate constraints is updated accordingly.
2014-05-09 18:58:48 -04:00
Andreas Hansson
c735ef6cb0 mem: Merge DRAM page-management calculations
This patch treats the closed page policy as yet another case of
auto-precharging, and thus merges the code with that used for the
other policies.
2014-05-09 18:58:48 -04:00
Andreas Hansson
87f4c956c4 mem: Add DRAM power states to the controller
This patch adds power states to the controller. These states and the
transitions can be used together with the Micron power model. As a
more elaborate use-case, the transitions can be used to drive the
DRAMPower tool.

At the moment, the power-down modes are not used, and this patch
simply serves to capture the idle, auto refresh and active modes. The
patch adds a third state machine that interacts with the refresh state
machine.
2014-05-09 18:58:48 -04:00
Andreas Hansson
babf072c1c mem: Ensure DRAM refresh respects timings
This patch adds a state machine for the refresh scheduling to
ensure that no accesses are allowed while the refresh is in progress,
and that all banks are propely precharged.

As part of this change, the precharging of banks of broken out into a
method of its own, making is similar to how activations are dealt
with. The idle accounting is also updated to ensure that the refresh
duration is not added to the time that the DRAM is in the idle state
with all banks precharged.
2014-05-09 18:58:48 -04:00
Andreas Hansson
5c2c3f598e mem: Make DRAM read/write switching less conservative
This patch changes the read/write event loop to use a single event
(nextReqEvent), along with a state variable, thus joining the two
control flows. This change makes it easier to follow the state
transitions, and control what happens when.

With the new loop we modify the overly conservative switching times
such that the write-to-read switch allows bank preparation to happen
in parallel with the bus turn around. Similarly, the read-to-write
switch uses the introduced tRTW constraint.
2014-05-09 18:58:48 -04:00
Mitch Hayenga
a15b713cba mem: Squash prefetch requests from downstream caches
This patch squashes prefetch requests from downstream caches,
so that they do not steal cachelines away from caches closer
to the cpu.  It was originally coded by Mitch Hayenga and
modified by Aasheesh Kolli.
2014-05-09 18:58:46 -04:00
Sascha Bischoff
e940bac278 mem: Auto-generate CommMonitor trace file names
Splits the CommMonitor trace_file parameter into three parameters. Previously,
the trace was only enabled if the trace_file parameter was set, and would be
written to this file. This patch adds in a trace_enable and trace_compress
parameter to the CommMonitor.

No trace is generated if trace_enable is set to False. If it is set to True, the
trace is written to a file based on the name of the SimObject in the simulation
hierarchy. For example, system.cluster.il1_commmonitor.trc. This filename can be
overridden by additionally specifying a file name to the trace_file parameter
(more on this later).

The trace_compress parameter will append .gz to any filename if set to True.
This enables compression of the generated traces. If the file name already ends
in .gz, then no changes are made.

The trace_file parameter will override the name set by the trace_enable
parameter. In the case that the specified name does not end in .gz but
trace_compress is set to true, .gz is appended to the supplied file name.
2014-05-09 18:58:46 -04:00
Mitch Hayenga
a0d30f36a6 mem: Don't print out the data of a cache block
This never actually worked since it was printing out only a word
of the cache block and not the entire thing and doubly didn't work
csprintf overrides the %#x specifier and assumes a char* array is
actually a string.
2014-04-01 14:24:36 -05:00
Nilay Vaish
4ceeda20aa ruby: slicc: remove old documentation
Has not been maintained at all.  Since there is alternate documentation
available on gem5.org, no need to have this separately.
2014-04-19 09:00:31 -05:00
Nilay Vaish
183100b8cb ruby: slicc: slight change to rule for transitions
It had an unnecessary pairs token which is being removed.
2014-04-19 09:00:31 -05:00
Marco Elver
d9fa950396 ruby: recorder: Fix (de-)serializing with different cache block-sizes
Upon aggregating records, serialize system's cache-block size, as the
cache-block size can be different when restoring from a checkpoint. This way,
we can correctly read all records when restoring from a checkpoints, even if
the cache-block size is different.

Note, that it is only possible to restore from a checkpoint if the
desired cache-block size is smaller or equal to the cache-block size
when the checkpoint was taken; we can split one larger request into
multiple small ones, but it is not reliable to do the opposite.

Committed by: Nilay Vaish <nilay@cs.wisc.edu>
2014-04-19 09:00:30 -05:00
Nilay Vaish
d805e42b81 ruby: slicc: change enqueue statement
As of now, the enqueue statement can take in any number of 'pairs' as
argument.  But we only use the pair in which latency is the key.  This
latency is allowed to be either a fixed integer or a member variable of
controller in which the expression appears.  This patch drops the use of pairs
in an enqueue statement.  Instead, an expression is allowed which will be
interpreted to be the latency of the enqueue.  This expression can anything
allowed by slicc including a constant integer or a member variable.
2014-04-08 13:26:30 -05:00
Nilay Vaish
e689c00b16 ruby: coherence protocols: drop the phrase IntraChip
The phrase is no longer valid since we do not distinguish between
inter and intra chip communication.
2014-04-08 13:26:29 -05:00
Andreas Hansson
a00383a40a mem: Track DRAM read/write switching and add hysteresis
This patch adds stats for tracking the number of reads/writes per bus
turn around, and also adds hysteresis to the write-to-read switching
to ensure that the queue does not oscilate around the low threshold.
2014-03-23 11:12:14 -04:00
Andreas Hansson
7c18691db1 mem: Rename SimpleDRAM to a more suitable DRAMCtrl
This patch renames the not-so-simple SimpleDRAM to a more suitable
DRAMCtrl. The name change is intended to ensure that we do not send
the wrong message (although the "simple" in SimpleDRAM was originally
intended as in cleverly simple, or elegant).

As the DRAM controller modelling work is being presented at ISPASS'14
our hope is that a broader audience will use the model in the future.

--HG--
rename : src/mem/SimpleDRAM.py => src/mem/DRAMCtrl.py
rename : src/mem/simple_dram.cc => src/mem/dram_ctrl.cc
rename : src/mem/simple_dram.hh => src/mem/dram_ctrl.hh
2014-03-23 11:12:12 -04:00
Andreas Hansson
3dd1587afc mem: Change memory defaults to be more representative
Make the default memory type DDR3-1600 x64, and use the open-adaptive
page policy. This change is aiming to ensure that users by default are
using a realistic memory system.
2014-03-23 11:12:10 -04:00
Wendy Elsasser
bbbae677ed mem: Add close adaptive paging policy to DRAM controller model
This patch adds a second adaptive page policy to the DRAM controller,
closing the page unless there are already queued accesses to the open
page.
2014-03-23 11:12:08 -04:00
Andreas Hansson
03a1aed803 mem: DRAM controller tidying up
Minor tidying up and removing of redundant code, including the
printing of queue state every million accesses.
2014-03-23 11:12:06 -04:00
Andreas Hansson
bc83eb2197 mem: Fix bug in DRAM bytes per activate
This patch ensures that we do not sample the bytes per activate when
the row has already been closed.
2014-03-23 11:12:05 -04:00
Andreas Hansson
116985d661 mem: Limit the accesses to a page before forcing a precharge
This patch adds a basic starvation-prevention mechanism where a DRAM
page is forced to close after a certain number of accesses. The limit
is combined with the open and open-adaptive page policy and if reached
causes an auto-precharge.
2014-03-23 11:12:03 -04:00
Andreas Hansson
6557741311 mem: Make DRAM write queue draining more aggressive
This patch changes the triggering condition for the write draining
such that we grab the opportunity to issue writes if there are no
reads waiting (as opposed to waiting for the writes to reach the high
threshold). As a result, we potentially drain some of the writes in read
idle periods (if any).

A low threshold is added to be able to control how many write bursts
are kept in the memory controller queue (acting as on-chip storage).

The high and low thresholds are updated to sensible values for a 32/64
size write buffer. Note that the thresholds should be adjusted along
with the queue sizes.

This patch also adds some basic initialisation sanity checks and moves
part of the initialisation to the constructor.
2014-03-23 11:12:01 -04:00
Neha Agarwal
43abaf518f mem: DDR3 config for comparing with DRAMSim2
This patch adds a new DDR3 configuration to match with the parameters
that are specified in one of the DDR3 configs used in DRAMSim2.
2014-03-23 11:11:56 -04:00
Andreas Hansson
7e7b67472a mem: More descriptive address-mapping scheme names
This patch adds the row bits to the name of the address mapping
schemes to make it more clear that all the current schemes places the
row bits as the most significant bits.
2014-03-23 11:11:53 -04:00
Andreas Hansson
9ac4f781ec ruby: Move Ruby debug flags to ruby dir and remove stale options
This patch moves the Ruby-related debug flags to the ruby
sub-directory, and also removes the state SConsopts that add the
no-longer-used NO_VECTOR_BOUNDS_CHECK.
2014-03-23 11:11:48 -04:00
Andreas Hansson
9f018d2f5a mem: Include the DRAMSim2 wrapper in NULL build
This patch makes sure DRAMSim2 is included in a build of the NULL ISA.
2014-03-23 11:11:44 -04:00
Sascha Bischoff
548d47ea2c mem: CommMonitor trace warn on non-timing mode
Add a warning to the CommMonitor which will alert the user if they try
and record a trace when the system is not in timing mode.
2014-03-23 11:11:40 -04:00
Nilay Vaish
52a83c1d0e ruby: consumer: avoid accessing wakeup times when waking up
Each consumer object maintains a set of tick values when the object is supposed
to wakeup and do some processing.  As of now, the object accesses this set both
when scheduling a wakeup event and when the object actually wakes up.  The set
is accessed during wakeup to remove the current tick value from the set.  This
functionality is now being moved to the scheduling function where ticks are
removed at a later time.
2014-03-20 09:14:14 -05:00
Nilay Vaish
4b67ada89e ruby: garnet: convert network interfaces into clocked objects
This helps in configuring the network interfaces from the python script and
these objects no longer rely on the network object for the timing information.
2014-03-20 09:14:14 -05:00
Nilay Vaish
4f7ef51efb ruby: slicc: code refactor 2014-03-20 09:14:14 -05:00