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

[Mike Kravetz <mkravetz@sequent.com>]

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                                 mkravetz@sequent.com
IBM Linux Technology Center
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