[PATCH] D81981: [PGO] Supplement PGO profile with Sample profile

[Rong Xu via llvm-commits]

On Wed, Jun 17, 2020 at 3:07 PM Wei Mi via Phabricator <
reviews at reviews.llvm.org> wrote:

> wmi added a comment.
>
> In D81981#2099070 <https://reviews.llvm.org/D81981#2099070>, @davidxl
> wrote:
>
> > I think it is good to have an entry counter always, so that the profile
> dump is more readable. Do you have data showing the instrumentation
> overhead and profile size impact (clang and some large app)?
>
>
> Yes, I tried clang. The instrumentation runtime overhead increases by
> about 0.8%. The raw profile size increases by 1.8%. The zipped profile size
> increases by 0.15%.
> Right now in the patch, inserting entry counter is guarded by a flag with
> default value being false.
>
> How did you test clang. This is for one file or for the whole clang?
To me, 0.8% is close to nothing.
My previous patch shows much more than this for a highly threaded program.

>
> Repository:
>   rL LLVM
>
> CHANGES SINCE LAST ACTION
>   https://reviews.llvm.org/D81981/new/
>
> https://reviews.llvm.org/D81981
>
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20200618/943b1014/attachment.html>