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This enhances MOESI_AMD_Base-dir DmaWrite to enable partial writes. This is currently done by assuming a full cache line, invalidating caches, and transitioning back to unblocked state. The enhanced write supports partial writes (i.e., smaller than cache line size) by first reading memory, merging the modified data, and then writing back to memory. Implementation of this mirrors that of DmaRead in terms of state. This means for each DmaRead state (BDR_PM, BDR_Pm, and BDR_M) there is a write analogue (BDW_PM, BDW_Pm, and BDR_M) and the BDR_P state is removed. Furthermore, this enhanced DmaWrite ... actually writes data to memory instead of relying on DirectoryEntry / backing store for correct data. There are two possible state transitions for DmaWrite now. (1) Memory data arrives before probe response and (2) probe response arrives before memory data. In case (1), probe data overwrites memory data and merges the partial write using the TBE write mask then updates write mask to 'filled' state. In case (2), probe data is merged with the partial data using the TBE write mask then updates write mask to 'filled' state. The memory data will then be clobbered by copying the TBE data over the response since the write mask is now full. Change-Id: I1eebb882b464c4c5ee5fd60932fd38d271ada4d7 Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/57410 Reviewed-by: Matthew Poremba <matthew.poremba@amd.com> Maintainer: Matthew Poremba <matthew.poremba@amd.com> Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com> Maintainer: Matt Sinclair <mattdsinclair@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, 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.