Re: BFS vs. mainline scheduler benchmarks and measurements

From: Ingo Molnar
Date: Sat Sep 19 2009 - 16:22:50 EST



* Felix Fietkau <nbd@xxxxxxxxxxx> wrote:

> Ingo Molnar wrote:
> > * Felix Fietkau <nbd@xxxxxxxxxxx> wrote:
> >> I did some tests with BFS v230 vs CFS on Linux 2.6.30 on a different
> >> MIPS device (Atheros AR2317) with 180 MHz and 16 MB RAM. When running
> >> iperf tests, I consistently get the following results when running the
> >> transfer from the device to my laptop:
> >>
> >> CFS: [ 5] 0.0-60.0 sec 107 MBytes 15.0 Mbits/sec
> >> BFS: [ 5] 0.0-60.0 sec 119 MBytes 16.6 Mbits/sec
> >>
> >> The transfer speed from my laptop to the device are the same with BFS
> >> and CFS. I repeated the tests a few times just to be sure, and I will
> >> check vmstat later.
> >
> > Which exact mainline kernel have you tried? For anything performance
> > related running latest upstream -git (currently at 202c467) would be
> > recommended.
>
> I used the OpenWrt-patched 2.6.30. Support for the hardware that I
> tested with hasn't been merged upstream yet. Do you think that the
> scheduler related changes after 2.6.30 are relevant for non-SMP
> performance as well? If so, I'll work on a test with latest upstream
> -git with the necessary patches when I have time for it.

Dont know - it's hard to tell what happens without basic analysis tools.
Is there _any_ way to profile what happens on that system? (Do hrtimers
work on it that could be used to profile it?)

Ingo
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