forked from OSchip/llvm-project
4719c52455
Summary: This is a follow-on to D49217 which simplifies and optimises the implementation of the segmented array. In this patch we co-locate the book-keeping for segments in the `__xray::Array<T>` with the data it's managing. We take the chance in this patch to actually rename `Chunk` to `Segment` to better align with the high-level description of the segmented array. With measurements using benchmarks landed in D48879, we've identified that calls to `pthread_getspecific` started dominating the cycles, which led us to revert the change made in D49217 to use C++ thread_local initialisation instead (it reduces the cost by a huge margin, since we save one PLT-based call to pthread functions in the hot path). In particular, this is in `__xray::getThreadLocalData()`. We also took the opportunity to remove the least-common-multiple based calculation and instead pack as much data into segments of the array. This greatly simplifies the API of the container which hides as much of the implementation details as possible. For instance, we calculate the number of elements we need for the each segment internally in the Array instead of making it part of the type. With the changes here, we're able to get a measurable improvement on the performance of profiling mode on top of what D48879 already provides. Depends on D48879. Reviewers: kpw, eizan Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D49363 llvm-svn: 337343 |
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| cmake | ||
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| include | ||
| lib | ||
| test | ||
| unittests | ||
| utils | ||
| www | ||
| .arcconfig | ||
| .gitignore | ||
| CMakeLists.txt | ||
| CODE_OWNERS.TXT | ||
| CREDITS.TXT | ||
| LICENSE.TXT | ||
| README.txt | ||
README.txt
Compiler-RT ================================ This directory and its subdirectories contain source code for the compiler support routines. Compiler-RT is open source software. You may freely distribute it under the terms of the license agreement found in LICENSE.txt. ================================