Re: interactive task starvation

[Mike Galbraith <efault@gmx.de>]

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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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