From: Mike Galbraith <efault@gmx.de>
To: Con Kolivas <con@kolivas.org>
Cc: "Artem S. Tashkinov" <t.artem@lycos.com>, linux-kernel@vger.kernel.org
Subject: Re: HT (Hyper Threading) aware process scheduling doesn't work as it should
Date: Mon, 31 Oct 2011 12:42:28 +0100 [thread overview]
Message-ID: <1320061348.6389.18.camel@marge.simson.net> (raw)
In-Reply-To: <1479015.f2tEjKr9vR@quad>
On Mon, 2011-10-31 at 21:06 +1100, Con Kolivas wrote:
> On Sun, 30 Oct 2011 07:57:12 PM Artem S. Tashkinov wrote:
> > I've found out that even on Linux 3.0.8 the process scheduler doesn't
> > correctly distributes the load amongst virtual CPUs. E.g. on a 4-core
> > system (8 total virtual CPUs) the process scheduler often run some
> > instances of four different tasks on the same physical CPU.
>
> > Any thoughts? comments? I think this is quite a serious problem.
>
> Intense cache locality logic, power saving concepts, cpu frequency governor
> behaviour and separate runqueues per CPU within the current CPU process
> scheduler in the current mainline linux kernel will ocasionally do this. Some
> workloads will be better, while others will be worse. Feel free to try my BFS
> cpu scheduler if you wish a CPU process scheduler that spreads work more
> evenly across CPUs.
>
> Alas the last version I synced up with will not apply cleanly past about 3.0.6
> I believe:
>
> http://ck.kolivas.org/patches/bfs/3.0.0/3.0-sched-bfs-413.patch
Yeah, it handles independent tasks well, but cache misses can be
excruciatingly painful for the others.
Q6600 box, configs as identical as possible, tbench 8
3.0.6-bfs413 728.6 MB/sec
3.0.8 1146.7 MB/sec
-Mike
next prev parent reply other threads:[~2011-10-31 11:42 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-30 19:57 Artem S. Tashkinov
2011-10-30 21:26 ` Henrique de Moraes Holschuh
2011-10-30 21:51 ` Artem S. Tashkinov
2011-10-31 9:16 ` Henrique de Moraes Holschuh
2011-10-31 9:40 ` Artem S. Tashkinov
2011-10-31 11:58 ` Henrique de Moraes Holschuh
2011-11-01 4:14 ` Zhu Yanhai
2011-11-01 5:15 ` ffab ffa
2011-10-31 18:59 ` Chris Friesen
2011-11-01 6:01 ` Mike Galbraith
2011-10-30 22:12 ` Arjan van de Ven
2011-10-30 22:29 ` Artem S. Tashkinov
2011-10-31 3:19 ` Yong Zhang
2011-10-31 8:18 ` Artem S. Tashkinov
2011-10-31 10:06 ` Con Kolivas
2011-10-31 11:42 ` Mike Galbraith [this message]
2011-11-01 0:41 ` Con Kolivas
2011-11-01 0:58 ` Gene Heskett
2011-11-01 5:08 ` Mike Galbraith
2011-11-03 8:18 ` Ingo Molnar
2011-11-03 9:44 ` Artem S. Tashkinov
2011-11-03 10:29 ` Ingo Molnar
2011-11-03 12:42 ` Henrique de Moraes Holschuh
2011-11-03 13:06 ` Artem S. Tashkinov
2011-11-03 13:00 ` Mike Galbraith
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