From: Nick Piggin <nickpiggin@yahoo.com.au>
To: Con Kolivas <kernel@kolivas.org>
Cc: Chen@vger.kernel.org, Kenneth W <kenneth.w.chen@intel.com>,
linux-kernel@vger.kernel.org
Subject: Re: bug in sched.c:activate_task()
Date: Tue, 05 Oct 2004 13:14:43 +1000 [thread overview]
Message-ID: <416211A3.8060806@yahoo.com.au> (raw)
In-Reply-To: <cone.1096943670.717018.10082.502@pc.kolivas.org>
Con Kolivas wrote:
> Chen, Kenneth W writes:
>
>> Update p->timestamp to "now" in activate_task() doesn't look right
>> to me at all. p->timestamp records last time it was running on a
>> cpu. activate_task shouldn't update that variable when it queues
>> a task on the runqueue.
>>
>> This bug (and combined with others) triggers improper load balancing.
>
>
> The updated timestamp was placed there by Ingo to detect on-runqueue
> time. If it is being used for load balancing then it is being used in
> error.
>
Load balancing wants to know if a task is considered cache hot.
next prev parent reply other threads:[~2004-10-05 3:15 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-10-05 2:16 bug in sched.c:activate_task() Chen, Kenneth W
2004-10-05 2:34 ` Con Kolivas
2004-10-05 3:14 ` Nick Piggin [this message]
2004-10-05 4:45 ` Con Kolivas
2004-10-05 5:05 ` Peter Williams
2004-10-05 6:10 ` Nick Piggin
2004-10-05 6:31 ` Ingo Molnar
2004-10-05 6:36 ` Con Kolivas
2004-10-05 6:54 ` Ingo Molnar
2004-10-05 6:59 ` Con Kolivas
2004-10-05 7:08 ` Nick Piggin
2004-10-05 7:09 ` Ingo Molnar
2004-10-05 17:30 ` Chen, Kenneth W
2004-10-05 17:25 ` Chen, Kenneth W
2004-10-05 6:57 ` Nick Piggin
2004-10-05 8:19 ` Ingo Molnar
2004-10-05 17:44 ` Chen, Kenneth W
-- strict thread matches above, loose matches on Subject: below --
2004-10-05 22:46 Chen, Kenneth W
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