From: Andrew Morton <akpm@osdl.org>
To: "Chen, Kenneth W" <kenneth.w.chen@intel.com>
Cc: linux-kernel@vger.kernel.org, axboe@suse.de
Subject: Re: Direct io on block device has performance regression on 2.6.x kernel
Date: Wed, 9 Mar 2005 14:44:58 -0800 [thread overview]
Message-ID: <20050309144458.2cbc554e.akpm@osdl.org> (raw)
In-Reply-To: <200503092159.j29LxIg26267@unix-os.sc.intel.com>
"Chen, Kenneth W" <kenneth.w.chen@intel.com> wrote:
>
> > Did you generate a kernel profile?
>
> Top 40 kernel hot functions, percentage is normalized to kernel utilization.
>
> _spin_unlock_irqrestore 23.54%
> _spin_unlock_irq 19.27%
Cripes.
Is that with CONFIG_PREEMPT? If so, and if you disable CONFIG_PREEMPT,
this cost should be accounting the the spin_unlock() caller and we can see
who the culprit is. Perhaps dio->bio_lock.
next prev parent reply other threads:[~2005-03-10 4:29 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-03-09 1:39 Direct io on block device has performance regression on 2.6.x kernel Chen, Kenneth W
2005-03-09 6:27 ` Andrew Morton
2005-03-09 17:21 ` Chen, Kenneth W
2005-03-09 20:04 ` Andrew Morton
2005-03-09 21:59 ` Chen, Kenneth W
2005-03-09 22:44 ` Andrew Morton [this message]
2005-03-10 1:11 ` Chen, Kenneth W
2005-03-10 1:33 ` Andrew Morton
2005-03-10 1:44 ` Chen, Kenneth W
2005-03-10 2:25 ` Andrew Morton
2005-03-10 3:47 ` Chen, Kenneth W
2005-03-10 4:04 ` David Lang
2005-03-10 4:10 ` Andrew Morton
2005-03-10 4:15 ` Direct io on block device has performance regression on 2.6.xkernel David Lang
2005-03-10 4:09 ` Direct io on block device has performance regression on 2.6.x kernel Andrew Morton
2005-03-10 18:31 ` Chen, Kenneth W
2005-03-10 20:30 ` Andrew Morton
2005-03-10 21:42 ` Chen, Kenneth W
2005-03-10 22:01 ` Andrew Morton
2005-03-10 4:28 ` Andrew Vasquez
-- strict thread matches above, loose matches on Subject: below --
2005-03-09 1:53 Chen, Kenneth W
2005-03-09 22:18 Chen, Kenneth W
2005-03-09 23:23 ` Andi Kleen
2005-03-09 23:52 ` Jesse Barnes
2005-03-09 23:52 ` Jesse Barnes
2005-03-10 1:00 ` Chen, Kenneth W
2005-03-10 0:57 ` Chen, Kenneth W
2005-03-10 1:24 Chen, Kenneth W
2005-03-10 2:04 Chen, Kenneth W
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