Messages in this thread | | | Date | Thu, 29 Mar 2001 13:26:50 -0800 (PST) | From | David Lang <> | Subject | Re: linux scheduler limitations? |
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2.2 or 2.4 kernel?
the 2.4 does a MUCH better job of dealing with large numbers of processes.
David Lang
On Thu, 29 Mar 2001, Fabio Riccardi wrote:
> Date: Thu, 29 Mar 2001 13:19:05 -0800 > From: Fabio Riccardi <fabio@chromium.com> > To: linux-kernel@vger.kernel.org > Subject: linux scheduler limitations? > > Hello, > > I'm working on an enhanced version of Apache and I'm hitting my head > against something I don't understand. > > I've found a (to me) unexplicable system behaviour when the number of > Apache forked instances goes somewhere beyond 1050, the machine > suddently slows down almost top a halt and becomes totally unresponsive, > until I stop the test (SpecWeb). > > Profiling the kernel shows that the scheduler and the interrupt handler > are taking most of the CPU time. > > I understand that there must be a limit to the number of processes that > the scheduler can efficiently handle, but I would expect some sort of > gradual performance degradation when increasing the number of tasks, > instead I observe that by increasing Apache's MaxClient linit by as > little as 10 can cause a sudden transition between smooth working with > lots (30-40%) of CPU idle to a total lock-up. > > Moreover the max number of processes is not even constant. If I increase > the server load gradually then I manage to have 1500 processes running > with no problem, but if the transition is sharp (the SpecWeb case) than > I end-up having a lock up. > > Anybody seen this before? Any clues? > > - Fabio > > > - > 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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