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When running multithreaded programs in SE-mode with DerivO3CPU model, there are cases that two or more cores have page faults on the same page in nearby ticks (can be at the same tick) when fetching instructions (more likely) or accessing data. When these cores try come to the commit stage in nearby ticks/cycles, they will try to handle the faults (without clobbering). Then the first core will ask for a physical page frame to map with the virtual page. In the previous version, the right next core that tries to handle the fault will hit a panic condition in the EmulationPageTable::map(...) as the page has been mapped and this page fault is not to clobber the existing mapping. In this changeset, if it is found that the page has been mapped and it is not to clobber the existing mapping, it will return without further mapping activities as the page fault has been handled previously. Jira Issue: https://gem5.atlassian.net/browse/GEM5-798 Change-Id: I9bb1163f9d1379c6fed9725101e4400fefdc8079 Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/39515 Reviewed-by: Jason Lowe-Power <power.jg@gmail.com> Maintainer: Jason Lowe-Power <power.jg@gmail.com> Tested-by: kokoro <noreply+kokoro@google.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/about, and for more information about building the simulator and getting started please see http://www.gem5.org/documentation and http://www.gem5.org/documentation/learning_gem5/introduction. 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/documentation/general_docs/building 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 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/documentation/general_docs/building for more details and options. 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. If you have questions, please send mail to gem5-users@gem5.org Enjoy using gem5 and please share your modifications and extensions.