From: "Artem S. Tashkinov" <t.artem@lycos.com>
To: yong.zhang0@gmail.com
Cc: arjan@infradead.org, linux-kernel@vger.kernel.org, mingo@elte.hu,
peterz@infradead.org
Subject: Re: Re: Re: HT (Hyper Threading) aware process scheduling doesn't work as it should
Date: Mon, 31 Oct 2011 08:18:35 +0000 (GMT) [thread overview]
Message-ID: <1963557866.68748.1320049115504.JavaMail.mail@webmail05> (raw)
In-Reply-To: 20111031031907.GB18057@zhy
>
> (Cc'ing more people)
>
> Maybe you can also show your test case here?
>
The test case is perfectly outlined in the first message I posted to LKML but I
can repeat it for you ( https://lkml.org/lkml/2011/10/30/106 ).
On a HT enabled completely idle system run as many different tasks as you have
real CPU cores, e.g. on an Intel Core i7 2600 CPU, that will be four tasks.
For the best performance all tasks should be attached to different physical cores.
However often the opposite behaviour can be observed, the process scheduler
binds pairs of tasks to virtual HT cores of the same physical CPU module, e.g.
in theory you should get this distribution of tasks: 1:3:5:7 but often I get this
distribution 1:6:7:8 (three physical cores loaded instead of four) or 1:2:7:8 (two
physical cores loaded instead of four).
Artem
next prev parent reply other threads:[~2011-10-31 8:18 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-30 19:57 HT (Hyper Threading) aware process scheduling doesn't work as it should 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 [this message]
2011-10-31 10:06 ` Con Kolivas
2011-10-31 11:42 ` Mike Galbraith
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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