Re: interactive task starvation

Mike Galbraith
2006-03-20T07:06:59Z

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On Fri, 2006-03-17 at 18:15 +0100, Mike Galbraith wrote:
> Problem solved. I now know why the starvation logic doesn't work.
> Wakeups. In the face of 10+ copies of httpd constantly waking up, it
> seems it just takes ages to get around to switching arrays.
>
> With the (urp) patch below, I now get...
>
> [root]:# time netstat|grep :81|wc -l
> 1648
>
> real 0m27.735s
> user 0m0.158s
> sys 0m0.111s
> [root]:# time netstat|grep :81|wc -l
> 1817
>
> real 0m13.550s
> user 0m0.121s
> sys 0m0.186s
> [root]:# time netstat|grep :81|wc -l
> 1641
>
> real 0m17.022s
> user 0m0.132s
> sys 0m0.143s
> [root]:#

For those interested in these kind of things, here are the numbers for
2.6.16-rc6-mm2 with my [tarball] throttle patches applied...

[root]:# time netstat|grep :81|wc -l
1681

real 0m1.525s
user 0m0.141s
sys 0m0.136s
[root]:# time netstat|grep :81|wc -l
1491

real 0m0.356s
user 0m0.130s
sys 0m0.114s
[root]:# time netstat|grep :81|wc -l
1527

real 0m0.343s
user 0m0.129s
sys 0m0.114s
[root]:# time netstat|grep :81|wc -l
1568

real 0m0.512s
user 0m0.112s
sys 0m0.138s

...while running with the same apache loadavg of over 10, and tunables
set to server mode (0,0).

<plug>
Even a desktop running with these settings is so interactive that I
could play a game of Maelstrom (asteroids like thing) while doing a make
-j30 in slow nfs mount and barely feel it. In a local filesystem, I
could't feel it at all, so I added a thud 3, irman2 and a bonnie -s 2047
for good measure. Try that with stock :)
</plug>

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