[PATCH] D59941: [DebugInfo] Improve handling of clobbered fragments

Tue Apr 2 01:08:19 PDT 2019

dstenb added a comment.

In D59941#1447940 <https://reviews.llvm.org/D59941#1447940>, @aprantl wrote:

> What's the performance impact of this change? Specifically, I'd be interested in the wall clock time difference for building an RelWithDebInfo+asan build of clang.

I applied the whole patch series (including the follow-up patch, D59942 <https://reviews.llvm.org/D59942>), and ran through five compilations with respectively without the patches using the following Cmake configuration:

  cmake -G Ninja -DCMAKE_BUILD_TYPE=RelWithDebInfo -DLLVM_USE_SANITIZER=Address -DLLVM_TARGETS_TO_BUILD='X86' -DLLVM_PARALLEL_LINK_JOBS=4 -DLLVM_USE_LINKER=gold

I ran the compilations on an 8-thread i7-8650U machine with 32 GBs of RAM.

This gave the following measurements:

  Master:
  real time: 37m34s, 37m32s, 37m31s, 37m30s, 37m28s
  average real time: 37m31s

  Patched:
  real time: 37m40s, 37m38s, 41m43s, 37m34s, 37m37s
  average real time: 38m26s

As seen, the wall clock for four of the five patched runs is increased by a few seconds compared to master. The run that increases by four minutes I suspect is simply due to some scheduled work during the night.

Repository:
  rL LLVM

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D59941/new/

https://reviews.llvm.org/D59941