Re: CFQ IO scheduler patch series - AIM7 DBase results on a 16-way IA64

["Alan D. Brunelle" <Alan.Brunelle@hp.com>]

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