Re: massive_intr on CFS, BFS, and EDF

From: Raistlin
Date: Sat Sep 26 2009 - 03:22:30 EST


On Fri, 2009-09-25 at 16:46 -0600, Chris Friesen wrote:
> On 09/25/2009 04:37 PM, Peter Zijlstra wrote:
> > afaiu he doesn't, he simply splits the task's wcet between parent and
> > child and (intends?) to feed back on child exit.
>
> How does this work if we have one parent task that forks off a bunch of
> kids like massive_intr? Does each child get half the bandwidth of the
> previous child?
>
Yes, that's exactly how I think it goes... Moreover, also the parent's
bandwidth is halved at each fork, which make things very odd in
workloads like massive_intr! :-(

> Right...so would it perhaps be more interesting to try a modified test
> where each child's bandwidth is equal and small enough that there is no
> oversubscription?
>
So right! I think that should be the way to go, and I'll try to do
something like this as soon as I can... I promise... :-D

Regards,
Dario

--
<<This happens because I choose it to happen!>> (Raistlin Majere)
----------------------------------------------------------------------
Dario Faggioli, ReTiS Lab, Scuola Superiore Sant'Anna, Pisa (Italy)

http://blog.linux.it/raistlin / raistlin@xxxxxxxxx /
dario.faggioli@xxxxxxxxxx

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