Messages in this thread | | | Date | Sun, 24 Jun 2007 22:31:48 +0200 | From | Ingo Molnar <> | Subject | Re: [patch] CFS scheduler, -v18 |
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* Willy Tarreau <w@1wt.eu> wrote:
> > > I have no idea about what version brought that unexpected > > > behaviour, but it's clearly something which needs to be tracked > > > down. > > > > hm, the two problems might be related. Could you try v17 perhaps? In > > v18 i have 'unified' all the sched.c's between the various kernel > > releases, maybe that brought in something unexpected on 2.6.20.14. > > (perhaps try v2.6.21.5 based cfs too?) > > Well, forget this, I'm nuts. I'm sorry, but I did not set any of the > -R and -S parameter on ocbench, which means that all the processes ran > at full speed and did not sleep. The load distribution was not fair, > but since they put a lot of stress on the X server, I think it might > be one of the reasons for the unfairness. I got the same behaviour > with -v17, -v9 and even 2.4 ! It told me something was wrong on my > side ;-) > > I've retried with 50%/50% run/sleep, and it now works like a charm. > It's perfectly smooth with both small and long run/sleep times > (between 1 and 100 ms). I think that with X saturated, it might > explain why I only had one CPU running at 100% !
ah, great! :-) My testbox needs a 90% / 10% ratio between sleep/run for an 8x8 matrix of ocbench tasks to not overload the X server. Once the overload happens X starts penalizing certain clients it finds abusive (i think), and that mechanism seems to be wall-clock based and it thus brings in alot of non-determinism and skews the clients.
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