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Updating the message counter and enqueue times when adding blocked messages back to the queue does not make a lot of sense since these messages are not new arrivals. More importantly, this may lead to starvation. See the scenario below: 1) Request A for a blocked line X arrives 2) A is handled; X is blocked so A is stalled 3) Request B for X arrives; Reponse for X arrives 4) Response is handled; X unblocked; A added back to the request queue 5) B is handled ahead of A (since A's arrival was updated); X may become blocked again If new requests keep comming for X, A may will be stalled forever. Change-Id: Icad79f3f716a870e91cb3455437b8b3c35f130ac Signed-off-by: Tiago Muck <tiago.muck@arm.com> Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18412 Tested-by: kokoro <noreply+kokoro@google.com> Reviewed-by: Jason Lowe-Power <jason@lowepower.com> Reviewed-by: Matthew Poremba <matthew.poremba@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.