From: Nick Piggin <nickpiggin@yahoo.com.au>
To: John Hawkes <hawkes@sgi.com>
Cc: John Hawkes <hawkes@google.engr.sgi.com>,
John Hawkes <hawkes@oss.sgi.com>, Ingo Molnar <mingo@elte.hu>,
jbarnes@sgi.com, linux-kernel@vger.kernel.org, akpm@osdl.org
Subject: Re: [PATCH, 2.6.9] improved load_balance() tolerance for pinned tasks
Date: Tue, 26 Oct 2004 09:59:45 +1000 [thread overview]
Message-ID: <417D9371.4050305@yahoo.com.au> (raw)
In-Reply-To: <001c01c4baac$056ae7d0$6700a8c0@comcast.net>
John Hawkes wrote:
>
> To reiterate: this is probably reproducible on smaller SMP systems, too.
> Just do a 'runon' (using sys_sched_setaffinity) of ~200 (or more) small
> computebound processes on a single CPU.
>
Yeah I tried that with a handful... I'll try again with 200.
> My patch -- that has load_balance() skip over (busiest->active_balance = 1)
> trigger that starts up active_load_balance() -- does seem to reduce the
> frequency of bursts of long-running activity of the migration thread, but
> those burst of activity are still there, with migration_thread consuming
> 75-95% of its CPU for several seconds (as observed by 'top'). I have not yet
> determined what's happening. It might be an artifact of how long it takes to
> do those 'runon' startups of the computebound processes.
>
Hmm... it would be hard to believe that it is all to do with
migrating tasks... but its possible I guess.
I'll also look into it if I can reproduce the problem here.
next prev parent reply other threads:[~2004-10-26 1:25 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-10-20 19:36 [PATCH, 2.6.9] improved load_balance() tolerance for pinned tasks John Hawkes
2004-10-20 19:59 ` Ingo Molnar
2004-10-22 13:08 ` Nick Piggin
2004-10-22 19:38 ` John Hawkes
[not found] ` <00ee01c4b870$030b80f0$6700a8c0@comcast.net>
2004-10-23 4:27 ` Nick Piggin
2004-10-25 16:02 ` John Hawkes
2004-10-25 23:59 ` Nick Piggin [this message]
2004-10-30 0:21 ` Matthew Dobson
-- strict thread matches above, loose matches on Subject: below --
2004-10-22 19:20 John Hawkes
2004-10-23 4:22 ` Nick Piggin
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