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Currently when RLC queues (user mode queues) are mapped, the read/write pointers of the ring buffer are set to zero. However, these queues could be unmapped and then remapped later. In that situation the read/write pointers should be the previous value before unmapping occurred. Since the read pointer gets reset to zero, the queue begins reading from the start of the ring, which usually contains older packets. There is a 99% chance those packets contain addresses which are no longer in the page tables which will cause a page fault. To fix this we update the MQD with the current read/write pointer values and then writeback the MQD to memory when the queue is unmapped. This requires adding a pointer to the MQD and the host address of the MQD where it should be written back to. The interface for registering RLC queue is also simplified. Since we need to pass the MQD anyway, we can get values from it as well. Fixes b+tree and streamcluster from rodinia (when using RLC queues). Change-Id: Ie5dad4d7d90ea240c3e9f0cddf3e844a3cd34c4f Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/65791 Tested-by: kokoro <noreply+kokoro@google.com> Maintainer: Matt Sinclair <mattdsinclair@gmail.com> Reviewed-by: Matt Sinclair <mattdsinclair@gmail.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.