This is a discussion on Re: 2 x quad-core system is slower that 2 x dual core on FreeBSD - FreeBSD ; Hi Robert Watson wrote: > Evidence in-hand seems to suggest that 8 core systems work very well for > most users, and reflect a significant performance increase with 7.0 over > previous FreeBSD releases. I disagree with that. Heavily loaded ...
Robert Watson wrote:
> Evidence in-hand seems to suggest that 8 core systems work very well for
> most users, and reflect a significant performance increase with 7.0 over
> previous FreeBSD releases.
I disagree with that. Heavily loaded Apache, MySQL, Postgres does not work well.
>>> The right path forwawrd at this point is to diagnosis the problems
>>> and work on fixing them in 8-CURRENT, and assuming they are not
>>> highly disruptive, MFC them for FreeBSD 7.1.
>> I believe at least the bug with lockmgr contention should be fixed
>> before release.
> Could you point me at the specific proposed change in question? I don't
> think I've seen it come across re@ as a potential merge request.
> Changing locking primitives close to a release is, FYI, a risky
> business, as while it may improve performance in specific cases, we may
> not have a lot of information about more general cases. We also risk
> opening up previously nascent race conditions in lock consumers.
Kris sent me proof of concept patch that helped much against high lockmgr
contention. After applying this patch 8-core server become faster that 4-core.
But, again, it's still slower than Linux.
Here's the patch:
Here's Kris saying that it helps:
I'm not sure it will help to MySQL and Prostgres, but symptoms are mostly identical.
With best regards,
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