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Message-ID: <46518D8A.10609@hp.com>
Date: Mon, 21 May 2007 08:16:10 -0400
From: "Alan D. Brunelle" <Alan.Brunelle@...com>
To: Jens Axboe <jens.axboe@...cle.com>
Cc: linux-kernel@...r.kernel.org
Subject: Re: CFQ IO scheduler patch series - AIM7 DBase results on a 16-way
IA64
Jens Axboe wrote:
> On Tue, May 01 2007, Alan D. Brunelle wrote:
>
>> Jens Axboe wrote:
>>
>>> On Mon, Apr 30 2007, Alan D. Brunelle wrote:
>>>
>>>> The results from a single run of an AIM7 DBase load on a 16-way ia64 box
>>>> (64GB RAM + 144 FC disks) showed a slight regression (~0.5%) by adding
>>>> in this patch. (Graph can be found at
>>>> http://free.linux.hp.com/~adb/cfq/cfq_dbase.png ) It is only a single
>>>> set of runs, on a single platform, but it is something to keep an eye on
>>>> as the regression showed itself across the complete run.
>>>>
>>> Do you know if this regression is due to worse IO performance, or
>>> increased system CPU usage?
>>>
>> We performed two point runs yesterday (20,000 and 50,000 tasks) and here
>> are the results:
>>
>> Kernel Tasks Jobs per Minute %sys (avg)
>> ------ ----- --------------- ----------
>> 2.6.21 20000 60,831.1 39.83%
>> CFQ br 20000 60,237.4 40.80%
>> -0.98% +2.44%
>>
>> 2.6.21 50000 60,881.6 40.43%
>> CFQ br 50000 60,400.6 40.80%
>> -0.79% +0.92%
>>
>> So we're seeing a slight IO performance regression with a slight
>> increase in %system with the CFQ branch. (A chart of the complete run
>> values is up on http://free.linux.hp.com/~adb/cfq/cfq_20k50k.png ).
>>
>
> Alan, can you repeat that same run with this patch applied? It
> reinstates the cfq lookup hash, which could account for increased system
> utilization.
>
Hi Jens -
This test was performed over the weekend, results are updated on
http://free.linux.hp.com/~adb/cfq/cfq_dbase.png
Alan
-
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