6b25cfbb98
The purpose of this script is to measure the performance effect
of an lld change in a statistically sound way, automating all the
tedious parts of doing so. It copies the test case into /tmp as well as
running the test binaries from /tmp to reduce the influence on the test
machine's storage medium on the results. It accounts for measurement
bias caused by binary layout (using the --randomize-section-padding
flag to link the test binaries) and by environment variable size
(implemented by hyperfine [1]). Runs of the base and test case are
interleaved to account for environmental factors which may influence
the result due to the passage of time. The results of running hyperfine
are collected into a results.csv file in the output directory and
may be analyzed by the user with a tool such as ministat.
Requirements: Linux host, hyperfine [2] in $PATH, run from a build
directory configured to use ninja and a recent version of lld that
supports --randomize-section-padding, /tmp is tmpfs.
[1] 3cedcc38d0/src/util/randomized_environment_offset.rs (L1)
[2] https://github.com/sharkdp/hyperfine
Reviewers: rnk, MaskRay, smithp35
Reviewed By: rnk
Pull Request: https://github.com/llvm/llvm-project/pull/138367
The LLVM Compiler Infrastructure
Welcome to the LLVM project!
This repository contains the source code for LLVM, a toolkit for the construction of highly optimized compilers, optimizers, and run-time environments.
The LLVM project has multiple components. The core of the project is itself called "LLVM". This contains all of the tools, libraries, and header files needed to process intermediate representations and convert them into object files. Tools include an assembler, disassembler, bitcode analyzer, and bitcode optimizer.
C-like languages use the Clang frontend. This component compiles C, C++, Objective-C, and Objective-C++ code into LLVM bitcode -- and from there into object files, using LLVM.
Other components include: the libc++ C++ standard library, the LLD linker, and more.
Getting the Source Code and Building LLVM
Consult the Getting Started with LLVM page for information on building and running LLVM.
For information on how to contribute to the LLVM project, please take a look at the Contributing to LLVM guide.
Getting in touch
Join the LLVM Discourse forums, Discord chat, LLVM Office Hours or Regular sync-ups.
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