Re: CFQ IO scheduler patch series - AIM7 DBase results on a 16-wayIA64

From: Alan D. Brunelle
Date: Tue May 01 2007 - 08:04:00 EST


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
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