Messages in this thread | | | Date | Thu, 29 Mar 2001 13:55:11 -0800 | From | Fabio Riccardi <> | Subject | Re: linux scheduler limitations? |
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I'm using 2.4.2-ac26, but I've noticed the same behavior with all the 2.4 kernels I've seen so far.
I haven't even tried on 2.2
- Fabio
David Lang wrote:
> 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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