Re: [Lse-tech] Re: multi-queue scheduler update

[David Lang]

another thing that would be interesting is what is the overhead on UP or
small (2-4 way) SMP machines

David Lang

On Thu, 18 Jan 2001, Mike Kravetz wrote:

> Date: Thu, 18 Jan 2001 16:52:25 -0800
> From: Mike Kravetz <[e-mail]>
> To: Andrea Arcangeli <[e-mail]>
> Cc: [e-mail], [e-mail]
> Subject: Re: [Lse-tech] Re: multi-queue scheduler update
>
> On Fri, Jan 19, 2001 at 01:26:16AM +0100, Andrea Arcangeli wrote:
> > On Thu, Jan 18, 2001 at 03:53:11PM -0800, Mike Kravetz wrote:
> > > Here are some very preliminary numbers from sched_test_yield
> > > (which was previously posted to this (lse-tech) list by Bill
> > > Hartner).  Tests were run on a system with 8 700 MHz Pentium
> > > III processors.
> > >
> > >                            microseconds/yield
> > > # threads      2.2.16-22           2.4        2.4-multi-queue
> > > ------------   ---------         --------     ---------------
> > > 16               18.740            4.603         1.455
> >
> > I remeber the O(1) scheduler from Davide Libenzi was beating the mainline O(N)
> > scheduler with over 7 tasks in the runqueue (actually I'm not sure if the
> > number was 7 but certainly it was under 10). So if you also use a O(1)
> > scheduler too as I guess (since you have a chance to run fast on the lots of
> > tasks running case) the most interesting thing is how you score with 2/4/8
> > tasks in the runqueue (I think the tests on the O(1) scheduler patch was done
> > at max on a 2-way SMP btw). (the argument for which Davide's patch wasn't
> > included is that most machines have less than 4/5 tasks in the runqueue at the
> > same time)
> >
> > Andrea
>
> Thanks for the suggestion.  The only reason I hesitated to test with
> a small number of threads is because I was under the assumption that
> this particular benchmark may have problems if the number of threads
> was less than the number of processors.  I'll give the tests a try
> with a smaller number of threads.  I'm also open to suggestions for
> what benchmarks/test methods I could use for scheduler testing.  If
> you remember what people have used in the past, please let me know.
>
> --
> Mike Kravetz                                 [e-mail]
> IBM Linux Technology Center
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