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When a message triggers a transition that has actions which allocate TBEs, the generated code automatically includes a check for the TBETable size before executing any action. If the table is full, the transition returns TransitionResult_ResourceStall and no more messages from the buffer are handled (until the next cycle). This behavior may lead to deadlocks in the MOESI_CMP_directory protocol since events triggered by the response queue may allocate TBEs (e.g. L2 replacements triggered by the response queue). If the table is full, the queue is stalled preventing other responses from freeing TBEs. This patch fixes this by handling WRITEBACK_DIRTY_DATA/CLEAN_DATA messages as requests and WB_ACK/WB_NACK as responses. All controllers are changed to work with the new types. With this fix, responses are always handled first in all controllers, and no response triggers TBE allocations. Change-Id: I377c0ec4f06d528e9f0541daf3dcc621184f2524 Signed-off-by: Tiago Muck <tiago.muck@arm.com> Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18408 Tested-by: kokoro <noreply+kokoro@google.com> Reviewed-by: Matthew Poremba <matthew.poremba@amd.com> Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com> Reviewed-by: John Alsop <johnathan.alsop@amd.com> Maintainer: Jason Lowe-Power <jason@lowepower.com>
This is the gem5 simulator. The main website can be found at http://www.gem5.org A good starting point is http://www.gem5.org/Introduction, and for more information about building the simulator and getting started please see http://www.gem5.org/Documentation and http://www.gem5.org/Tutorials. To build gem5, you will need the following software: g++ or clang, Python (gem5 links in the Python interpreter), SCons, SWIG, zlib, m4, and lastly protobuf if you want trace capture and playback support. Please see http://www.gem5.org/Dependencies for more details concerning the minimum versions of the aforementioned tools. Once you have all dependencies resolved, type 'scons build/<ARCH>/gem5.opt' where ARCH is one of ALPHA, ARM, NULL, MIPS, POWER, SPARC, or X86. This will build an optimized version of the gem5 binary (gem5.opt) for the the specified architecture. See http://www.gem5.org/Build_System for more details and options. With the simulator built, have a look at http://www.gem5.org/Running_gem5 for more information on how to use gem5. The basic source release includes these subdirectories: - configs: example simulation configuration scripts - ext: less-common external packages needed to build gem5 - src: source code of the gem5 simulator - system: source for some optional system software for simulated systems - tests: regression tests - util: useful utility programs and files To run full-system simulations, you will need compiled system firmware (console and PALcode for Alpha), kernel binaries and one or more disk images. Please see the gem5 download page for these items at http://www.gem5.org/Download If you have questions, please send mail to gem5-users@gem5.org Enjoy using gem5 and please share your modifications and extensions.