Re: 20% performance drop on PostgreSQL 9.2 from kernel 3.5.3 to3.6-rc5 on AMD chipsets - bisected

[Linus Torvalds]

On Fri, Sep 14, 2012 at 2:40 PM, Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> wrote:
>
> The problem the patch is trying to address is not having to scan an
> entire package for idle cores on every wakeup now that packages are
> getting stupid big.

No, it does something *else* too. That whole "left-right" logic to
(according to the commit message) "prevent bouncing" is entirely new,
afaik.

So it is *not* just about avoiding to have to scan the whole package.
It changes actual semantics too. No?

            Linus
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/