Commit graph

1323 commits

Author SHA1 Message Date
Ali Saidi
4412046041 cpu: include set in o3/commit_impl.
While the majority of compilers seemed to pickup set from else where,
one version of gcc 4.7 complains, so explictly add it.
2013-02-15 17:40:08 -05:00
Ali Saidi
7ae06a3b3b cpu: fix case with o3 cpu blocking and unblocking decode in cycle
Fix a case in the O3 CPU where the decode stage blocks and unblocks in a
single cycle sending both signals to fetch which causes an assert or worse.
The previous check could never work before since the status was set to Blocked
before a test for the status being Unblocking was executed.
2013-02-15 17:40:08 -05:00
Ali Saidi
b84bd3028c cpu: Fix a livelock in the o3 cpu.
Check if an instruction just enabled interrupts and we've previously had an
interrupt pending that was not handled because interrupts were subsequently
disabled before the pipeline reached a place to handle the interrupt. In that
case squash now to make sure the interrupt is handled.
2013-02-15 17:40:07 -05:00
Nilay Vaish ext:(%2C%20Timothy%20Jones%20%3Ctimothy.jones%40cl.cam.ac.uk%3E)
dbeabedaf0 branch predictor: move out of o3 and inorder cpus
This patch moves the branch predictor files in the o3 and inorder directories
to src/cpu/pred. This allows sharing the branch predictor across different
cpu models.

This patch was originally posted by Timothy Jones in July 2010
but never made it to the repository.

--HG--
rename : src/cpu/o3/bpred_unit.cc => src/cpu/pred/bpred_unit.cc
rename : src/cpu/o3/bpred_unit.hh => src/cpu/pred/bpred_unit.hh
rename : src/cpu/o3/bpred_unit_impl.hh => src/cpu/pred/bpred_unit_impl.hh
rename : src/cpu/o3/sat_counter.hh => src/cpu/pred/sat_counter.hh
2013-01-24 12:28:51 -06:00
Andrea Pellegrini
11d5ffa108 o3 cpu: fix zero reg problem
There was an issue w/ the rename logic, which would assign a previous physical
register to the ZeroReg architectural register in x86.  This issue was giving
problems for instructions squashed in threads w/ ID different from 0,
sometimes allowing non-mispredicted instructions to obtain a value different
from zero when reading the zeroReg.
2013-01-22 00:13:28 -06:00
Nilay Vaish
fc57ae6401 x86, cpu: corrects 270c9a75e91f, take over decoder on cpu switch
The changes made by the changeset 270c9a75e91f do not work well with switching
of cpus. The problem is that decoder for the old thread context holds state
that is not taken over by the new decoder.

This patch adds a takeOverFrom() function to Decoder class in each ISA. Except
for x86, functions in other ISAs are blank. For x86, the function copies state
from the old decoder to the new decoder.
2013-01-22 00:10:10 -06:00
Joel Hestness
1429d21244 O3 IEW: Make incrWb and decrWb clearer
Move the increment/decrement of wbOutstanding outside of the comparison
in incrWb and decrWb in the IEW. This also fixes a compiler bug with gcc
4.4.7, which incorrectly optimizes "-- ==" as "-=".
2013-01-19 15:14:54 -06:00
Nilay Vaish
5b6f972750 ruby: remove calls to g_system_ptr->getTime()
This patch further removes calls to g_system_ptr->getTime() where ever other
clocked objects are available for providing current time.
2013-01-17 13:10:12 -06:00
Nilay Vaish
f7c0ba406e base simple cpu: removes commented out code about cache ops 2013-01-12 22:11:16 -06:00
Nilay Vaish
25ec278a0b x86: Changes to decoder, corrects 9376
The changes made by the changeset 9376 were not quite correct. The patch made
changes to the code which resulted in decoder not getting initialized correctly
when the state was restored from a checkpoint.

This patch adds a startup function to each ISA object. For x86, this function
sets the required state in the decoder. For other ISAs, the function is empty
right now.
2013-01-12 22:09:48 -06:00
Andreas Sandberg
009970f59b cpu: Unify the serialization code for all of the CPU models
Cleanup the serialization code for the simple CPUs and the O3 CPU. The
CPU-specific code has been replaced with a (un)serializeThread that
serializes the thread state / context of a specific thread. Assuming
that the thread state class uses the CPU-specific thread state uses
the base thread state serialization code, this allows us to restore a
checkpoint with any of the CPU models.
2013-01-07 13:05:52 -05:00
Andreas Sandberg
e09e9fa279 cpu: Flush TLBs on switchOut()
This changeset inserts a TLB flush in BaseCPU::switchOut to prevent
stale translations when doing repeated switching. Additionally, the
TLB flushing functionality is exported to the Python to make debugging
of switching/checkpointing easier.

A simulation script will typically use the TLB flushing functionality
to generate a reference trace. The following sequence can be used to
simulate a handover (this depends on how drain is implemented, but is
generally the case) between identically configured CPU models:

  m5.drain(test_sys)
  [ cpu.flushTLBs() for cpu in test_sys.cpu ]
  m5.resume(test_sys)

The generated trace should normally be identical to a trace generated
when switching between identically configured CPU models or
checkpointing and resuming.
2013-01-07 13:05:48 -05:00
Andreas Sandberg
1814a85a05 cpu: Rewrite O3 draining to avoid stopping in microcode
Previously, the O3 CPU could stop in the middle of a microcode
sequence. This patch makes sure that the pipeline stops when it has
committed a normal instruction or exited from a microcode
sequence. Additionally, it makes sure that the pipeline has no
instructions in flight when it is drained, which should make draining
more robust.

Draining is controlled in the commit stage, which checks if the next
PC after a committed instruction is in microcode. If this isn't the
case, it requests a squash of all instructions after that the
instruction that just committed and immediately signals a drain stall
to the fetch stage. The CPU then continues to execute until the
pipeline and all associated buffers are empty.
2013-01-07 13:05:46 -05:00
Andreas Sandberg
9e8003148f cpu: Make sure that a drained atomic CPU isn't executing ucode
Currently, the atomic CPU can be in the middle of a microcode sequence
when it is drained. This leads to two problems:

 * When switching to a hardware virtualized CPU, we obviously can't
   execute gem5 microcode.

 * Since curMacroStaticInst is populated when executing microcode,
   repeated switching between CPUs executing microcode leads to
   incorrect execution.

After applying this patch, the CPU will be on a proper instruction
boundary, which means that it is safe to switch to any CPU model
(including hardware virtualized ones). This changeset fixes a bug
where the multiple switches to the same atomic CPU sometimes corrupts
the target state because of dangling pointers to the currently
executing microinstruction.

Note: This changeset moves tick event descheduling from switchOut() to
drain(), which makes timing consistent between just draining a system
and draining /and/ switching between two atomic CPUs. This makes
debugging quite a lot easier (execution traces get the same timing),
but the latency of the last instruction before a drain will not be
accounted for correctly (it will always be 1 cycle).

Note 2: This changeset removes so_state variable, the locked variable,
and the tickEvent from checkpoints since none of them contain state
that needs to be preserved across checkpoints. The so_state is made
redundant because we don't use the drain state variable anymore, the
lock variable should never be set when the system is drained, and the
tick event isn't scheduled.
2013-01-07 13:05:46 -05:00
Andreas Sandberg
f9bcf46371 cpu: Make sure that a drained timing CPU isn't executing ucode
Currently, the timing CPU can be in the middle of a microcode sequence
or multicycle (stayAtPC is true) instruction when it is drained. This
leads to two problems:

 * When switching to a hardware virtualized CPU, we obviously can't
   execute gem5 microcode.

 * If stayAtPC is true we might execute half of an instruction twice
   when restoring a checkpoint or switching CPUs, which leads to an
   incorrect execution.

After applying this patch, the CPU will be on a proper instruction
boundary, which means that it is safe to switch to any CPU model
(including hardware virtualized ones). This changeset also fixes a bug
where the timing CPU sometimes switches out with while stayAtPC is
true, which corrupts the target state after a CPU switch or
checkpoint.

Note: This changeset removes the so_state variable from checkpoints
since the drain state isn't used anymore.
2013-01-07 13:05:46 -05:00
Andreas Sandberg
52ff37caa3 cpu: Fix broken thread context handover
The thread context handover code used to break when multiple handovers
were performed during the same quiesce period. Previously, the thread
contexts would assign the TC pointer in the old quiesce event to the
new TC. This obviously broke in cases where multiple switches were
performed within the same quiesce period, in which case the TC pointer
in the quiesce event would point to an old CPU.

The new implementation deschedules pending quiesce events in the old
TC and schedules a new quiesce event in the new TC. The code has been
refactored to remove most of the code duplication.
2013-01-07 13:05:46 -05:00
Andreas Sandberg
fca4fea769 cpu: Fix O3 LSQ debug dumping constness and formatting 2013-01-07 13:05:46 -05:00
Andreas Sandberg
8db27aa230 cpu: Fix broken squashAfter implementation in O3 CPU
Commit can currently both commit and squash in the same cycle. This
confuses other stages since the signals coming from the commit stage
can only signal either a squash or a commit in a cycle. This changeset
changes the behavior of squashAfter so that it commits all
instructions, including the instruction that requested the squash, in
the first cycle and then starts to squash in the next cycle.
2013-01-07 13:05:45 -05:00
Andreas Sandberg
a2077ccf02 o3 cpu: Remove unused variables 2013-01-07 13:05:45 -05:00
Andreas Sandberg
2cfe62adc4 cpu: Rename defer_registration->switched_out
The defer_registration parameter is used to prevent a CPU from
initializing at startup, leaving it in the "switched out" mode. The
name of this parameter (and the help string) is confusing. This patch
renames it to switched_out, which should be more descriptive.
2013-01-07 13:05:45 -05:00
Andreas Sandberg
f7da0fddd1 cpu: Remove unused params.hh header file in inorder CPU 2013-01-07 13:05:45 -05:00
Andreas Sandberg
a7e0cbeb36 cpu: Introduce sanity checks when switching between CPUs
This patch introduces the following sanity checks when switching
between CPUs:

 * Check that the set of new and old CPUs do not overlap. Having an
   overlap between the set of new CPUs and the set of old CPUs is
   currently not supported. Doing such a switch used to result in the
   following assertion error:
     BaseCPU::takeOverFrom(BaseCPU*): \
       Assertion `!new_itb_port->isConnected()' failed.

 * Check that all new CPUs are in the switched out state.

 * Check that all old CPUs are in the switched in state.
2013-01-07 13:05:44 -05:00
Andreas Sandberg
901258c22b cpu: Correctly call parent on switchOut() and takeOverFrom()
This patch cleans up the CPU switching functionality by making sure
that CPU models consistently call the parent on switchOut() and
takeOverFrom(). This has the following implications that might alter
current functionality:

 * The call to BaseCPU::switchout() in the O3 CPU is moved from
   signalDrained() (!) to switchOut().

 * A call to BaseSimpleCPU::switchOut() is introduced in the simple
   CPUs.
2013-01-07 13:05:44 -05:00
Andreas Sandberg
4ae02295d5 cpu: Unify SimpleCPU and O3 CPU serialization code
The O3 CPU used to copy its thread context to a SimpleThread in order
to do serialization. This was a bit of a hack involving two static
SimpleThread instances and a magic constructor that was only used by
the O3 CPU.

This patch moves the ThreadContext serialization code into two global
procedures that, in addition to the normal serialization parameters,
take a ThreadContext reference as a parameter. This allows us to reuse
the serialization code in all ThreadContext implementations.
2013-01-07 13:05:44 -05:00
Andreas Sandberg
6daada2701 cpu: Initialize the O3 pipeline from startup()
The entire O3 pipeline used to be initialized from init(), which is
called before initState() or unserialize(). This causes the pipeline
to be initialized from an incorrect thread context. This doesn't
currently lead to correctness problems as instructions fetched from
the incorrect start PC will be squashed a few cycles after
initialization.

This patch will affect the regressions since the O3 CPU now issues its
first instruction fetch to the correct PC instead of 0x0.
2013-01-07 13:05:44 -05:00
Andreas Sandberg
e2dad8236a cpu: Implement a flat register interface in thread contexts
Some architectures map registers differently depending on their mode
of operations. There is currently no architecture independent way of
accessing all registers. This patch introduces a flat register
interface to the ThreadContext class. This interface is useful, for
example, when serializing or copying thread contexts.
2013-01-07 13:05:44 -05:00
Andreas Sandberg
17b47d35e1 arch: Move the ISA object to a separate section
After making the ISA an independent SimObject, it is serialized
automatically by the Python world. Previously, this just resulted in
an empty ISA section. This patch moves the contents of the ISA to that
section and removes the explicit ISA serialization from the thread
contexts, which makes it behave like a normal SimObject during
serialization.

Note: This patch breaks checkpoint backwards compatibility! Use the
cpt_upgrader.py utility to upgrade old checkpoints to the new format.
2013-01-07 13:05:42 -05:00
Andreas Sandberg
7eb0fb8b6e cpu: Check that the memory system is in the correct mode
This patch adds checks to all CPU models to make sure that the memory
system is in the correct mode at startup and when resuming after a
drain.  Previously, we only checked that the memory system was in the
right mode when resuming. This is inadequate since this is a
configuration error that should be detected at startup as well as when
resuming. Additionally, since the check was done using an assert, it
wasn't performed when NDEBUG was set (e.g., the fast target).
2013-01-07 13:05:41 -05:00
Andreas Hansson
ccb6c64047 cpu: Share the send functionality between traffic generators
This patch moves the packet creating and sending to a member function
in the shared base class to avoid code duplication.
2013-01-07 13:05:37 -05:00
Andreas Hansson
1da209140c cpu: Add support for protobuf input for the trace generator
This patch adds support for reading input traces encoded using
protobuf according to what is done in the CommMonitor.

A follow-up patch adds a Python script that can be used to convert the
previously used ASCII traces to protobuf equivalents. The appropriate
regression input is updated as part of this patch.
2013-01-07 13:05:37 -05:00
Andreas Hansson
35bdee72cb cpu: Encapsulate traffic generator input in a stream
This patch encapsulates the traffic generator input in a stream class
such that the parsing is not visible to the trace generator. The
change takes us one step closer to using protobuf-based input traces
for the trace replay.

The functionality of the current input stream is identical to what it
was, and the ASCII format remains the same for now.
2013-01-07 13:05:37 -05:00
Andreas Hansson
f22d3bb9c3 cpu: Fix the traffic gen read percentage
This patch fixes the computation that determines whether to perform a
read or a write such that the two corner cases (0 and 100) are both
more efficient and handled correctly.
2013-01-07 13:05:35 -05:00
Andreas Sandberg
3db3f83a5e arch: Make the ISA class inherit from SimObject
The ISA class on stores the contents of ID registers on many
architectures. In order to make reset values of such registers
configurable, we make the class inherit from SimObject, which allows
us to use the normal generated parameter headers.

This patch introduces a Python helper method, BaseCPU.createThreads(),
which creates a set of ISAs for each of the threads in an SMT
system. Although it is currently only needed when creating
multi-threaded CPUs, it should always be called before instantiating
the system as this is an obvious place to configure ID registers
identifying a thread/CPU.
2013-01-07 13:05:35 -05:00
Ali Saidi
69d419f313 o3: Fix issue with LLSC ordering and speculation
This patch unlocks the cpu-local monitor when the CPU sees a snoop to a locked
address. Previously we relied on the cache to handle the locking for us, however
some users on the gem5 mailing list reported a case where the cpu speculatively
executes a ll operation after a pending sc operation in the pipeline and that
makes the cache monitor valid. This should handle that case by invaliding the
local monitor.
2013-01-07 13:05:33 -05:00
Ali Saidi
5146a69835 cpu: rename the misleading inSyscall to noSquashFromTC
isSyscall was originally created because during handling of a syscall in SE
mode the threadcontext had to be updated. However, in many places this is used
in FS mode (e.g. fault handlers) and the name doesn't make much sense. The
boolean actually stops gem5 from squashing speculative and non-committed state
when a write to a threadcontext happens, so re-name the variable to something
more appropriate
2013-01-07 13:05:33 -05:00
Gabe Black
e17c375ddd Decoder: Remove the thread context get/set from the decoder.
This interface is no longer used, and getting rid of it simplifies the
decoders and code that sets up the decoders. The thread context had been used
to read architectural state which was used to contextualize the instruction
memory as it came in. That was changed so that the state is now sent to the
decoders to keep locally if/when it changes. That's significantly more
efficient.

Committed by: Nilay Vaish <nilay@cs.wisc.edu>
2013-01-04 19:00:45 -06:00
Nilay Vaish
c120273708 ruby: modify the directed tester to read/write streams
The directed tester supports only generating only read or only write accesses. The
patch modifies the tester to support streams that have both read and write accesses.
2012-12-11 10:05:55 -06:00
Erik Tomusk
3dc7e4f496 TournamentBP: Fix some bugs with table sizes and counters
globalHistoryBits, globalPredictorSize, and choicePredictorSize are decoupled.
globalHistoryBits controls how much history is kept, global and choice
predictor sizes control how much of that history is used when accessing
predictor tables. This way, global and choice predictors can actually be
different sizes, and it is no longer possible to walk off the predictor arrays
and cause a seg fault.

There are now individual thresholds for choice, global, and local saturating
counters, so that taken/not taken decisions are correct even when the
predictors' counters' sizes are different.

The interface for localPredictorSize has been removed from TournamentBP because
the value can be calculated from localHistoryBits.

Committed by: Nilay Vaish <nilay@cs.wisc.edu>
2012-12-06 09:31:06 -06:00
Malek Musleh
150e9b8c68 inorder cpu: add missing DPRINTF argument
Committed by: Nilay Vaish <nilay@cs.wisc.edu>
2012-12-06 05:25:40 -06:00
Nathanael Premillieu
eb899407c5 o3 cpu: remove some unused buggy functions in the lsq
Committed by: Nilay Vaish <nilay@cs.wisc.edu>
2012-12-06 04:36:51 -06:00
Andreas Sandberg
b81a977e6a sim: Move the draining interface into a separate base class
This patch moves the draining interface from SimObject to a separate
class that can be used by any object needing draining. However,
objects not visible to the Python code (i.e., objects not deriving
from SimObject) still depend on their parents informing them when to
drain. This patch also gets rid of the CountedDrainEvent (which isn't
really an event) and replaces it with a DrainManager.
2012-11-02 11:32:01 -05:00
Andreas Sandberg
eb703a4b4e cpu: O3 add a header declaring the DerivO3CPU
SWIG needs a complete declaration of all wrapped objects. This patch
adds a header file with the DerivO3CPU class and includes it in the
SWIG interface.

--HG--
rename : src/cpu/o3/cpu_builder.cc => src/cpu/o3/deriv.cc
2012-11-02 11:32:01 -05:00
Andreas Sandberg
ebe65a394b cpu: Add header files for checker CPUs
In order to create reliable SWIG wrappers, we need to include the
declaration of the wrapped class in the SWIG file. Previously, we
didn't expose the declaration of checker CPUs. This patch adds header
files for such CPUs and include them in the SWIG wrapper.

--HG--
rename : src/cpu/dummy_checker_builder.cc => src/cpu/dummy_checker.cc
rename : src/cpu/o3/checker_builder.cc => src/cpu/o3/checker.cc
2012-11-02 11:32:01 -05:00
Andreas Sandberg
c0ab52799c sim: Include object header files in SWIG interfaces
When casting objects in the generated SWIG interfaces, SWIG uses
classical C-style casts ( (Foo *)bar; ). In some cases, this can
degenerate into the equivalent of a reinterpret_cast (mainly if only a
forward declaration of the type is available). This usually works for
most compilers, but it is known to break if multiple inheritance is
used anywhere in the object hierarchy.

This patch introduces the cxx_header attribute to Python SimObject
definitions, which should be used to specify a header to include in
the SWIG interface. The header should include the declaration of the
wrapped object. We currently don't enforce header the use of the
header attribute, but a warning will be generated for objects that do
not use it.
2012-11-02 11:32:01 -05:00
Dam Sunwoo
81406018b0 ARM: dump stats and process info on context switches
This patch enables dumping statistics and Linux process information on
context switch boundaries (__switch_to() calls) that are used for
Streamline integration (a graphical statistics viewer from ARM).
2012-11-02 11:32:01 -05:00
Mrinmoy Ghosh
4440332bdd o3: Fix a couple of issues with the local predictor.
Fix some issues with the local predictor and the way it's indexed.
2012-11-02 11:32:00 -05:00
Nilay Vaish
07ce90f7aa memtest: move check on outstanding requests
The Memtest tester allows for only one request to be outstanding for a
particular physical address. The check has been written separately for
reads and writes. This patch moves the check earlier than its current
position so that it need not be written separately for reads and writes.
2012-10-15 17:27:17 -05:00
Andreas Hansson
2a740aa096 Port: Add protocol-agnostic ports in the port hierarchy
This patch adds an additional level of ports in the inheritance
hierarchy, separating out the protocol-specific and protocl-agnostic
parts. All the functionality related to the binding of ports is now
confined to use BaseMaster/BaseSlavePorts, and all the
protocol-specific parts stay in the Master/SlavePort. In the future it
will be possible to add other protocol-specific implementations.

The functions used in the binding of ports, i.e. getMaster/SlavePort
now use the base classes, and the index parameter is updated to use
the PortID typedef with the symbolic InvalidPortID as the default.
2012-10-15 08:12:35 -04:00
Andreas Hansson
93a159875a Fix: Address a few minor issues identified by cppcheck
This patch addresses a number of smaller issues identified by the code
inspection utility cppcheck. There are a number of identified leaks in
the arm/linux/system.cc (although the function only get's called once
so it is not a major problem), a few deletes in dev/x86/i8042.cc that
were not array deletes, and sprintfs where the character array had one
element less than needed. In the IIC tags there was a function
allocating an array of longs which is in fact never used.
2012-10-15 08:12:23 -04:00
Andreas Hansson
1c321b8847 Regression: Use CPU clock and 32-byte width for L1-L2 bus
This patch changes the CoherentBus between the L1s and L2 to use the
CPU clock and also four times the width compared to the default
bus. The parameters are not intending to fit every single scenario,
but rather serve as a better startingpoint than what we previously
had.

Note that the scripts that do not use the addTwoLevelCacheHiearchy are
not affected by this change.

A separate patch will update the stats.
2012-10-15 08:08:08 -04:00