From: Nick Piggin <piggin@cyberone.com.au>
To: Jeremy Higdon <jeremy@sgi.com>
Cc: linux-kernel@vger.kernel.org, jbarnes@sgi.com, axboe@suse.de
Subject: Re: [PATCH] per-backing dev unplugging #2
Date: Tue, 16 Mar 2004 18:46:44 +1100 [thread overview]
Message-ID: <4056B0E4.3090004@cyberone.com.au> (raw)
In-Reply-To: <20040316072046.GA636090@sgi.com>
Jeremy Higdon wrote:
>On Tue, Mar 16, 2004 at 05:36:18PM +1100, Nick Piggin wrote:
>
>>
>>Jeremy Higdon wrote:
>>
>>
>>>My tests were on an 8 CPU x 1300 MHz Altix with 64 disks.
>>>
>>>
>>>
>>Nice - so if you had enough IO capacity to saturate the CPUs it
>>might come close to a 4x improvement - and this sounds like one
>>of your baby systems?
>>
>
>Baby by cpu count, mid size by I/O capability. Extrapolations of
>this sort are fraught with peril. However, it is conceivable that
>we would end up with 4X the IOPS.
>
>
Well, it is more than 2x! What does a profile look like after
the patch, I wonder?
>>I wonder why nobody's complained about this before?
>>
>
>Well, some of us have, but probably not very loudly. I had
>naively believed that the global unplug was gone in 2.6.
>
>
I wasn't talking about SGI in particular, I just remember
people being very worried about making sure we can support
*thousands* of queues quite a while back.
Anyway, it's done now. And Jens' patch turned out to be pretty
simple and probably makes the code cleaner, anyway.
next prev parent reply other threads:[~2004-03-16 8:28 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-03-16 5:22 [PATCH] per-backing dev unplugging #2 Jeremy Higdon
2004-03-16 6:36 ` Nick Piggin
2004-03-16 7:20 ` Jeremy Higdon
2004-03-16 7:38 ` Jens Axboe
2004-03-17 0:23 ` Jeremy Higdon
2004-03-16 7:46 ` Nick Piggin [this message]
2004-03-16 7:29 ` Jens Axboe
2004-03-16 17:20 ` Jesse Barnes
-- strict thread matches above, loose matches on Subject: below --
2004-03-11 8:36 Jens Axboe
2004-03-11 22:44 ` Nathan Scott
2004-03-12 1:23 ` William Lee Irwin III
2004-03-12 6:41 ` Ingo Oeser
2004-03-12 8:04 ` Jens Axboe
2004-03-12 19:51 ` Chris Mason
2004-03-12 20:03 ` Andrew Morton
2004-03-12 20:02 ` Jens Axboe
2004-03-12 20:34 ` Chris Mason
2004-03-12 20:34 ` Jens Axboe
2004-03-12 20:41 ` Chris Mason
2004-03-12 20:51 ` Jens Axboe
2004-03-14 20:43 ` Chris Mason
2004-03-14 20:47 ` Jens Axboe
2004-03-14 20:57 ` Chris Mason
2004-03-14 21:04 ` Andrew Morton
2004-03-14 21:09 ` Jens Axboe
2004-03-15 21:58 ` Chris Mason
2004-03-12 20:06 ` Chris Mason
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