Re: [PATCH][2.6.7-rc3] Single Priority Array CPU Scheduler

From: Peter Williams
Date: Fri Jun 11 2004 - 19:11:29 EST


Shane Shrybman wrote:
Hi Peter,

I just started to try out your SPA scheduler patch and found that it is
noticeably sluggish when resizing a mozilla window on the desktop. I
have a profile of 2.6.7-rc3-spa and 2.6.7-rc2-mm2 and put them up at:
http://zeke.yi.org/linux/spa/ . There is also vmstat output there but it
doesn't look too helpful to me.

The test was basic and went like this:

x86, K7, UP, gnome desktop with mozilla (with a bunch of tabs) and a few
rxvts. cmdline= elevator=cfq profile=1

readprofile -r

grab a corner of my mozilla window and continually move it around for
several seconds

readprofile -v -m /boot/System.map-2.6.7-rc3|sort -rn +2|head -n30

do the same while dumping vmstat 1 to a file.

The kernel with your patch had a much harder time keeping up with the
window resizing. Moving the entire window did not seem too bad or not
too noticeable. I tried a similar test while running a kernel compile
(make -j3) and it made the window resizing _really_ slow to respond.

Thanks for the feedback, I'll add your test to those I perform myself.

Some of the control variables for this scheduler have rather arbitrary values at the moment and are likely to be non optimal. I'm in the process of making some of these variables modifiable at run time via /proc/sys to enable experimentation with different settings. Hopefully, this will enable settings that improve interactive performance to be established.

Once again, thanks for the feedback
Peter
--
Peter Williams pwil3058@xxxxxxxxxxxxxx

"Learning, n. The kind of ignorance distinguishing the studious."
-- Ambrose Bierce

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