Bug 111616 - On Zen2 7% 519.lbm_r regression between g:1d17d58c284fa8c3 (2023-09-14 02:39) and g:c8e9a75085f9725c (2023-09-18 13:09)
Summary: On Zen2 7% 519.lbm_r regression between g:1d17d58c284fa8c3 (2023-09-14 02:39)...
Status: RESOLVED FIXED
Alias: None
Product: gcc
Classification: Unclassified
Component: target (show other bugs)
Version: 14.0
: P3 normal
Target Milestone: ---
Assignee: Not yet assigned to anyone
URL:
Keywords: needs-bisection
Depends on:
Blocks: spec
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Reported: 2023-09-27 15:02 UTC by Filip Kastl
Modified: 2023-10-04 11:38 UTC (History)
3 users (show)

See Also:
Host: x86_64-linux
Target: x86_64-linux
Build:
Known to work:
Known to fail:
Last reconfirmed:

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Description Filip Kastl 2023-09-27 15:02:02 UTC 
On x86_64 AMD Zen2 machine with Ofast LTO PGO march=native mtune=native between commits g:1d17d58c284fa8c3 (2023-09-14 02:39) and g:c8e9a75085f9725c (2023-09-18 13:09) there is a 519.lbm_r 7% execution time regression.

Here is a plot of recent measurements:
https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.0=286.477.0

I confirmed this on another Zen2 machine. This time I measured 9% slowdown.
Comment 1 Filip Kastl 2023-10-04 11:38:46 UTC 
I'm not sure which commit fixed the slowdown but it is now gone. 519.lbm_r performance is back to where it was at g:1d17d58c284fa8c3.

Marking as fixed.