Messages in this thread | | | From | Con Kolivas <> | Subject | Re: [SCHED] wrong priority calc - SIMPLE test case | Date | Fri, 13 Jan 2006 12:32:01 +1100 |
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On Friday 13 January 2006 12:13, Con Kolivas wrote: > On Saturday 31 December 2005 00:52, Paolo Ornati wrote: > > WAS: [SCHED] Totally WRONG prority calculation with specific test-case > > (since 2.6.10-bk12) > > http://lkml.org/lkml/2005/12/27/114/index.html > > > > On Wed, 28 Dec 2005 10:26:58 +1100 > > > > Con Kolivas <kernel@kolivas.org> wrote: > > > The issue is that the scheduler interactivity estimator is a state > > > machine and can be fooled to some degree, and a cpu intensive task that > > > just happens to sleep a little bit gets significantly better priority > > > than one that is fully cpu bound all the time. Reverting that change is > > > not a solution because it can still be fooled by the same process > > > sleeping lots for a few seconds or so at startup and then changing to > > > the cpu mostly-sleeping slightly behaviour. This "fluctuating" > > > behaviour is in my opinion worse which is why I removed it. > > > > Trying to find a "as simple as possible" test case for this problem > > (that I consider a BUG in priority calculation) I've come up with this > > very simple program: > > Hi Paolo. > > Can you try the following patch on 2.6.15 please? I'm interested in how > adversely this affects interactive performance as well as whether it helps > your test case.
I should make it clear. This patch _will_ adversely affect interactivity because your test case desires that I/O bound tasks get higher priority, and this patch will do that. This means that I/O bound tasks will be more noticeable now. The question is how much do we trade off one for the other. We almost certainly are biased a little too much on the interactive side on the mainline kernel at the moment.
Cheers, Con - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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