Fixes a latency calculation bug for accesses during a cache line fill.
Under a cache miss, before the line is filled, accesses to the cache are
associated with a MSHR and marked as targets. Once the line fill completes,
MSHR target packets pay an additional latency of
"responseLatency + busSerializationLatency". However, the "whenReady"
field of the cache line is only set to an additional delay of
"busSerializationLatency". This lacks the responseLatency component of
the fill. It is possible for accesses that occur on the cycle of
(or briefly after) the line fill to respond without properly paying the
responseLatency. This also creates the situation where two accesses to the
same address may be serviced in an order opposite of how they were received
by the cache. For stores to the same address, this means that although the
cache performs the stores in the order they were received, acknowledgements
may be sent in a different order.
Adding the responseLatency component to the whenReady field preserves the
penalty that should be paid and prevents these ordering issues.
Committed by: Nilay Vaish <nilay@cs.wisc.edu>
There's not much to do about it other than disable the offending
warning anyway, so it's not worth terminating the build over.
Also suppress uninitialized variable warnings on gcc (happens
at least with gcc 4.4 and swig 1.3.40).
This patch adds a simple Python script that reads the protobuf-encoded
packet traces (not gzipped), and prints them to an ASCII trace file.
The script can also be used as a template for other packet output
formats.
This patch adds a simple Python script that reads a simple ASCII trace
format and encodes it as protobuf output compatible with the traffic
generator.
The script can also be used as a template for other packet input
formats that should be converted to the gem5 packet protobuf format.
This patch solves the corner case scenario where the sendRetryEvent could be
scheduled twice, when an io device stresses the IOcache in the system. This
should not be possible in the cache system.
This patch splits the retryList into a list of ports that are waiting
for the bus itself to become available, and a map that tracks the
ports where forwarding failed due to a peer not accepting the
packet. Thus, when a retry reaches the bus, it can be sent to the
appropriate port that initiated that transaction.
As a consequence of this patch, only ports that are really ready to go
will get a retry, thus reducing the amount of redundant failed
attempts. This patch also makes it easier to reason about the order of
servicing requests as the ports waiting for the bus are now clearly
FIFO and much easier to change if desired.
This patch introduces a variable to keep track of the retrying port
instead of relying on it being the front of the retryList.
Besides the improvement in readability, this patch is a step towards
separating out the two cases where a port is waiting for the bus to be
free, and where the forwarding did not succeed and the bus is waiting
for a retry to pass on to the original initiator of the transaction.
The changes made are currently such that the regressions are not
affected. This is ensured by always prioritizing the currently
retrying port and putting it back at the front of the retry list.
This patch adds an optional generic 64-bit identifier field to the
packet trace. This can be used to store the sequential number of the
instruction that gave rise to the packet, thread id, master id,
"sub"-master within a larger module etc. As the field is optional it
has a marginal cost if not used.
This patch adds an optional flags field to the packet trace to encode
the request flags that contain information about whether the request
is (un)cacheable, instruction fetch, preftech etc.
This patch changes the port in the CPU classes to use MasterPort
instead of the derived CpuPort. The functions of the CpuPort are now
distributed across the relevant subclasses. The port accessor
functions (getInstPort and getDataPort) now return a MasterPort
instead of a CpuPort. This simplifies creating derivative CPUs that do
not use the CpuPort.
Changeset 02321b16685f added m5_writefile to m5op_x86.S a second time,
which causes a compilation error on when compiling for x86. This
changeset reverts that changeset and fixes the error.
A recent set of patches added support for multiple clock domains to ruby.
I had made some errors while writing those patches. The sender was using
the receiver side clock while enqueuing a message in the buffer. Those
errors became visible while creating (or restoring from) checkpoints. The
errors also become visible when a multi eventq scenario occurs.
The message buffer node used to keep time in terms of Cycles. Since the
sender and the receiver can have different clock periods, storing node
time in cycles requires some conversion. Instead store the time directly
in Ticks.
A set of patches was recently committed to allow multiple clock domains
in ruby. In those patches, I had inadvertently made an incorrect use of
the clocks. Suppose object A needs to schedule an event on object B. It
was possible that A accesses B's clock to schedule the event. This is not
possible in actual system. Hence, changes are being to the Consumer class
so as to avoid such happenings. Note that in a multi eventq simulation,
this can possibly lead to an incorrect simulation.
There are two functions in the Consumer class that are used for scheduling
events. The first function takes in the relative delay over the current time
as the argument and adds the current time to it for scheduling the event.
The second function takes in the absolute time (in ticks) for scheduling the
event. The first function is now being moved to protected section of the
class so that only objects of the derived classes can use it. All other
objects will have to specify absolute time while scheduling an event
for some consumer.
The histogram for tracking outstanding counts per cycle is maintained
in the profiler. For a parallel implementation of the memory system, we
need that this histogram is maintained locally. Hence it will now be
kept in the sequencer itself. The resulting histograms will be merged
when the stats are printed.
These functions are currently implemented in one of the files related to Slicc.
Since these are purely C++ functions, they are better suited to be in the base
class.
This patch modifies ruby so that two controllers can be connected to each
other with only message buffers in between. Before this patch, all the
controllers had to be connected to the network for them to communicate
with each other. With this patch, one can have protocols where a controller
is not connected to the network, but communicates with another controller
through a message buffer.
The Topology class in Ruby does not need to inherit from SimObject class.
This patch turns it into a regular class. The topology object is now created
in the constructor of the Network class. All the parameters for the topology
class have been moved to the network class.
This patch comments out the inclusion of the inorder TLBUnit which is
only used in the 9-stage pipeline. With the TLBUnit present, gcc >=
4.6 in combination with LTO ends up throwing away the definition of
the TLBUnit destructor, and consequently fail to link. See
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53808 for more details
about the bug, and http://gcc.gnu.org/ml/gcc/2012-06/msg00397.html for
the discussion thread that also touches on similar issues seen with
clang.
tcmalloc_minimal doesn't support the heap checker on Debian, while
tcmalloc does. Instead of always linking with tcmalloc_minimal, if it
exists, we first check for tcmalloc and then use tcmalloc_minimal as a
fallback.
According to the tcmalloc readme, the recommended way of compiling
applications that make use of tcmalloc is to disable compiler
optimizations that make assumptions about malloc and friends. This
changeset adds the necessary compiler flags for both gcc and clang.
From the tcmalloc readme:
"NOTE: When compiling with programs with gcc, that you plan to link
with libtcmalloc, it's safest to pass in the flags
-fno-builtin-malloc -fno-builtin-calloc
-fno-builtin-realloc -fno-builtin-free
when compiling."
Python requires the flags in LINKFORSHARED to be added the linker
flags when linking with a statically with Python. Failing to do so can
lead to errors from the Python's dynamic module loader at start up.
--HG--
extra : rebase_source : e7a8daf72f4ede7ee5a4a5398a0b12e978a919b9
SWIG version 2.0.9 uses fully qualified module names despite of the
importing module being in the same package as the imported
module. This has the unfortunate consequence of causing the following
error when importing m5.internal.event:
Traceback (most recent call last):
File "<string>", line 1, in <module>
File "src/python/importer.py", line 75, in load_module
exec code in mod.__dict__
File "src/python/m5/__init__.py", line 35, in <module>
import internal
File "src/python/importer.py", line 75, in load_module
exec code in mod.__dict__
File "src/python/m5/internal/__init__.py", line 32, in <module>
import event
File "src/python/importer.py", line 75, in load_module
exec code in mod.__dict__
File "build/X86/python/swig/event.py", line 107, in <module>
class Event(m5.internal.serialize.Serializable):
AttributeError: 'module' object has no attribute 'internal'
When 'event' is loaded, it triggers 'serialize' to be loaded. However,
it seems like the dictionary of 'm5' isn't updated until after
__init__.py terminates, which means that 'event' never sees the
'internal' attribute on 'm5'. Older versions of SWIG didn't include
the fully qualified module name if the modules were in the same
package.
The traffic generator used to incorrectly determine the next state in
when state 0 had a non-zero probability. Due to the way the next
transition was determined, state 0 could never be entered other than
as an initial state. This changeset updates the transitition() method
to correctly handle such cases and cases where the transition matrix
is a 1x1 matrix.
This patch fixes a bug in the address range granularity
calculations. Previously it incorrectly used the high bit to establish
the size of the regions created, when it should really be looking at
the low bit.
This patch fixes an issue related to the table walker recycling
packets that still have a bus delay that is not accounted for. For
now, we simply ignore the values and reset them to zero.
This change fixes the switcheroo test that broke earlier this month. The code
that was checking for the pipeline being blocked wasn't checking for a pending
translation, only for a icache access.
The functional write code was assuming that all writes are block sized,
which may not be true for Ruby Requests. This bug can lead to a buffer
overflow.
Committed by: Nilay Vaish <nilay@cs.wisc.edu>
This check covers a case where a retry is called from the SimpleDRAM
causing a new request to appear before the DRAM itself schedules a
nextReqEvent. By adding this check, the event is not scheduled twice.
