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Currently, taking a checkpoint with a ruby cache involves moving all the dirty data in cache to memory. This is done by keeping **only** simulating the cache until all dirty data are flushed to the memory before taking the checkpoint. However, when the cache does not have dirty data, it is a problem if we keep simulating the cache. E.g., calling checkpoint caused the gem5 "empty event queue" assertion fault when running the ruby cache in atomic_noncaching mode. Since the mode bypasses the cache, all blocks are invalid and do not contain dirty data. Subsequently, there is no event placed to the event queue when we keep **only** simulating the cache before taking the checkpoint. This patch fixes this problem by checking if there is any actionable item when trying to move dirty data to memory. If there is no block contains dirty data, we simply choose not to continue simulating the cache before taking the checkpoint. Change-Id: Idfa09be51274c7fc8a340e9e33167f5b32d1b866 Signed-off-by: Hoa Nguyen <hoanguyen@ucdavis.edu> Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/69897 Reviewed-by: Jason Lowe-Power <power.jg@gmail.com> Tested-by: kokoro <noreply+kokoro@google.com> Maintainer: Bobby Bruce <bbruce@ucdavis.edu>
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, 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 these tools. Once you have all dependencies resolved, type 'scons build/<CONFIG>/gem5.opt' where CONFIG is one of the options in build_opts like ARM, NULL, MIPS, POWER, SPARC, X86, Garnet_standalone, etc. This will build an optimized version of the gem5 binary (gem5.opt) with the the specified configuration. See http://www.gem5.org/documentation/general_docs/building for more details and options. The main source tree includes these subdirectories: - build_opts: pre-made default configurations for gem5 - build_tools: tools used internally by gem5's build process. - configs: example simulation configuration scripts - ext: less-common external packages needed to build gem5 - include: include files for use in other programs - site_scons: modular components of the build system - 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 may need compiled system firmware, kernel binaries and one or more disk images, depending on gem5's configuration and what type of workload you're trying to run. Many of those resources can be downloaded from http://resources.gem5.org, and/or from the git repository here: https://gem5.googlesource.com/public/gem5-resources/ If you have questions, please send mail to gem5-users@gem5.org Enjoy using gem5 and please share your modifications and extensions.