lkml.org 
[lkml]   [2001]   [Mar]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: linux scheduler limitations?
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/
> >

-
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/

\
 
 \ /
  Last update: 2005-03-22 13:18    [W:0.296 / U:0.016 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site