[PATCH] D20401: [Lexer] Don't merge macro args from different macro files

Fri Sep 30 09:35:11 PDT 2022

nickdesaulniers added a comment.

In D20401#3824713 <https://reviews.llvm.org/D20401#3824713>, @sammccall wrote:

> Thanks Nick for the info! No kernel experience here, so if you have any particular suggestions about how to measure the workload you care about it'd be much appreciated (e.g. are particular files that are slow enough to measure in isolation, or is it better to do a full build)

@sammccall I wrote up instructions for how to profile a Linux kernel build with LLVM.
https://github.com/ClangBuiltLinux/profiling/tree/main/perf
A build on a 72+ threaded workstation should only take ~1 minute. Can you please give it a shot and let me know off-thread if you encounter any issues?
One thing I found about that workflow: just this week I upgraded to a zen2-based threadripper workstation. It appears that zen2 has issues using per-thread LBR.
https://www.spinics.net/lists/linux-perf-users/msg23103.html
(There's follow up responses that I don't see yet in the archive, but it looks like there's pending Linux kernel patches to get that working.)
https://lore.kernel.org/lkml/166155216401.401.5809694678609694438.tip-bot2@tip-bot2/
https://lore.kernel.org/lkml/20220829113347.295-1-ravi.bangoria@amd.com/
So you might want to ensure you're running those instructions on an intel box, for now. I'm also happy to hop on a virtual call with you and @hokein anytime.

Repository:
  rL LLVM

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D20401/new/

https://reviews.llvm.org/D20401