From: Andi Kleen <ak@muc.de>
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: Thu, 10 Mar 2005 00:23:09 +0100 [thread overview]
Message-ID: <m1r7iov1ya.fsf@muc.de> (raw)
In-Reply-To: <200503092218.j29MICg26503@unix-os.sc.intel.com> (Kenneth W. Chen's message of "Wed, 9 Mar 2005 14:18:12 -0800")
"Chen, Kenneth W" <kenneth.w.chen@intel.com> writes:
>
> Just to clarify here, these data need to be taken at grain of salt. A
> high count in _spin_unlock_* functions do not automatically points to
> lock contention. It's one of the blind spot syndrome with timer based
> profile on ia64. There are some lock contentions in 2.6 kernel that
> we are staring at. Please do not misinterpret the number here.
Why don't you use oprofileÂ>? It uses NMIs and can profile "inside"
interrupt disabled sections.
-Andi
next prev parent reply other threads:[~2005-03-09 23:26 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-03-09 22:18 Direct io on block device has performance regression on 2.6.x kernel Chen, Kenneth W
2005-03-09 23:23 ` Andi Kleen [this message]
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
-- strict thread matches above, loose matches on Subject: below --
2005-03-10 2:04 Chen, Kenneth W
2005-03-10 1:24 Chen, Kenneth W
2005-03-09 1:53 Chen, Kenneth W
2005-03-09 1:39 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
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 4:09 ` 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
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