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From: David Miller <davem@davemloft.net>
To: axboe@suse.de
Cc: linux-kernel@vger.kernel.org
Subject: Re: softirq considered harmful
Date: Thu, 10 Aug 2006 04:41:33 -0700 (PDT)	[thread overview]
Message-ID: <20060810.044133.50597818.davem@davemloft.net> (raw)
In-Reply-To: <20060810110627.GM11829@suse.de>

From: Jens Axboe <axboe@suse.de>
Date: Thu, 10 Aug 2006 13:06:27 +0200

> run_timer_softirq+0x0/0x18e: took 3750
> run_timer_softirq+0x0/0x18e: took 2595
> run_timer_softirq+0x0/0x18e: took 6265
> run_timer_softirq+0x0/0x18e: took 2608
> 
> So from 2.6 to 6.2msecs just that handler, auch. During normal running,
> the 2.6 msec variant triggers quite often.

It would be interesting to know what timers ran when
the overhead got this high.

You can probably track this with a per-cpu array
of pointers, have run_timer_softirq record the
t->func pointers into the array as it runs the
current slew of timers, then if the "took" is
very large dump the array.

  reply	other threads:[~2006-08-10 11:41 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-08-10 11:06 softirq considered harmful Jens Axboe
2006-08-10 11:41 ` David Miller [this message]
2006-08-10 12:26   ` Jens Axboe
2006-08-12 23:28 ` Andrew Morton
2006-08-13  0:43   ` David Miller
2006-08-13  0:45     ` Andrew Morton
2006-08-13  1:09       ` David Miller
2006-08-13  1:22         ` Andrew Morton
2006-08-14  7:37           ` Jens Axboe
2006-08-14  8:44             ` David Miller
2006-08-14  8:51               ` Jens Axboe
2006-08-14  7:34       ` Jens Axboe
2006-08-13 14:31   ` Jens Axboe

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