From: dasperry@comcast.net (dave_sperry@ieee.org)
To: Ingo Molnar <mingo@elte.hu>, Dave Sperry <dave_sperry@ieee.org>
Cc: linux-rt-users@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: Poor UDP performance using 2.6.21-rc5-rt5
Date: Mon, 02 Apr 2007 14:09:29 +0000 [thread overview]
Message-ID: <040220071409.15202.46110E98000A743600003B622205886172979D9D0A9F9C0E0B@comcast.net> (raw)
Thanks for all the input Ingo, Here's a list of all the permutations I've tried:
setup Thruput CPU% from cyclesoak
2.6.21-rc5 vanilla 935 29%
2.6.21-rc5-rt5 711 50% //basically all of 1 cpu
2.6.21-rc5-rt8 733 52%
2.6.21-rc5-rt8 824 64%
netperf @50
hardirq @50
softirq @50
2.6.21-rc5-rt8 937 74%
netperf @51
hardirq @50
softirq @50
2.6.21-rc5-rt8 106 8%
netperf @51
hardirq @49
softirq @50
2.6.21-rc5-rt8 233 14%
netperf @51
hardirq @49
softirq @48
2.6.21-rc5-rt8 67 5%
netperf @batch
hardirq @batch
softirq @batch
2.6.21-rc5-rt8 331 OFF
netperf @batch
hardirq @batch
softirq @batch
cyclesoak off
Any thoughts?
-Dave
-------------- Original message ----------------------
From: Ingo Molnar <mingo@elte.hu>
>
> * Dave Sperry <dave_sperry@ieee.org> wrote:
>
> > I checked the clock source and in both the vanilla and rt cases and
> > they were both acpi_pm
>
> ok, thanks for double-checking that.
>
> > Here's the oprofile for my vanilla case:
>
> i tried your workload and i think i managed to optimize it some more: i
> have uploaded the -rt8 kernel with these improvements included - could
> you try it? Is there any measurable improvement relative to -rt5?
>
> one more thing to improve netperf performance is to do this before
> running it:
>
> chrt -f -p 50 $$
>
> this will put netperf on the same priority level as the net hardirq and
> the net softirq (which both default to SCHED_FIFO:50), and should result
> in a (much) reduced context-switch rate.
>
> Or, if networking is not latency-critical, then you could move the net
> hardirq and softirq threads to SCHED_BATCH, and run netperf under
> SCHED_BATCH as well, using:
>
> chrt -b -p 0 $$
>
> and figuring out the active softirq hardirq thread PIDs and "chrt -b"
> -ing them too.
>
> Ingo
next reply other threads:[~2007-04-02 14:18 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-04-02 14:09 dave_sperry@ieee.org [this message]
2007-04-02 14:23 ` Poor UDP performance using 2.6.21-rc5-rt5 Ingo Molnar
-- strict thread matches above, loose matches on Subject: below --
2007-04-02 17:50 dave_sperry@ieee.org
2007-04-02 19:04 ` Ingo Molnar
2007-04-03 0:09 ` David Sperry
2007-04-03 6:43 ` Ingo Molnar
2007-04-03 8:51 ` Ingo Molnar
2007-04-02 17:17 dave_sperry@ieee.org
2007-04-01 19:15 Dave Sperry
2007-04-01 20:07 ` Nivedita Singhvi
2007-04-01 22:00 ` Dave Sperry
2007-04-02 5:55 ` Ingo Molnar
2007-04-02 6:30 ` Ingo Molnar
2007-04-02 7:21 ` Ingo Molnar
2007-04-02 8:17 ` Dave Sperry
2007-04-02 9:37 ` Ingo Molnar
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