Re: 20% performance drop on PostgreSQL 9.2 from kernel 3.5.3 to 3.6-rc5 on AMD chipsets - bisected

Borislav Petkov
2012-09-26T16:32:17Z

On Tue, Sep 25, 2012 at 10:21:28AM -0700, Linus Torvalds wrote:
> How does pgbench look? That's the one that apparently really wants to
> spread out, possibly due to user-level spinlocks. So I assume it will
> show the reverse pattern, with "kill select_idle_sibling" being the
> worst case. Sad, because it really would be lovely to just remove that
> thing ;)

Yep, correct. It hurts.

v3.6-rc7-1897-g28381f207bd7 (linus from 26/9 + tip/auto-latest) + performance governor

tps = 4574.570857 (including connections establishing)
tps = 4579.166159 (excluding connections establishing)

v3.6-rc7-1897-g28381f207bd7 (linus from 26/9 + tip/auto-latest) + performance governor + kill select_idle_sibling

tps = 2230.354093 (including connections establishing)
tps = 2231.412169 (excluding connections establishing)

--
Regards/Gruss,
Boris.