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This patch removes the NeedsWritable flag for all responses, as it is really only the request that needs a writable response. The response, on the other hand, should in these cases always provide the line in a writable state, as indicated by the hasSharers flag not being set. When we send requests that has NeedsWritable set, the response will always have the hasSharers flag not set. Additionally, there are cases where the request did not have NeedsWritable set, and we still get a writable response with the hasSharers flag not set. This never happens on snoops, but is used by downstream caches to pass ownership upstream. As part of this patch, the affected response types are updated, and the snoop filter is similarly modified to check only the hasSharers flag (as it should). A sanity check is also added to the packet class, asserting that we never look at the NeedsWritable flag for responses. No regressions are affected.
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.