Marcos Paulo de Souza@mpdesouza@floss.social
@ptesarik@infosec.exchange @ljs@mastodonapp.uk @gnutools@fosstodon.org @amonakov@mastodon.gamedev.place
It always amazes me how frustrating and complicated seemingly simple issues can get. Keep on! /me picks another popcorn box
Petr TesaΕΓk@ptesarik@infosec.exchange
@mpdesouza@floss.social Good.
I replaced the copyin caller _copy_from_iter with the GCC7 version. Slightly better now: down from -4.4% to -2.9%.
Now, I can continue replacing more callers until I replace the whole kernel and get the original performance, but that's rather pointless. Instead, since this first change seems to have some effect, let me try to understand why.
At this point, I believe it's related to the microarchitecture: I'm seeing this on 3rd Gen Intel Xeon Scalable (Ice Lake).
@ljs@mastodonapp.uk @gnutools@fosstodon.org @amonakov@mastodon.gamedev.place
