From: Roger Larsson <roger.larsson@norran.net>
To: george anzinger <george@mvista.com>,
Roger Larsson <roger.larsson@skelleftea.mail.telia.com>
Cc: linux-kernel@vger.kernel.org, Robert Love <rml@tech9.net>
Subject: Re: [PATCH] latency-profiling
Date: Thu, 20 Sep 2001 22:31:40 +0200 [thread overview]
Message-ID: <200109202036.f8KKaUv18307@maile.telia.com> (raw)
In-Reply-To: <200109200609.f8K69uQ26778@mailc.telia.com> <3BAA49B5.E02FA5E7@mvista.com>
In-Reply-To: <3BAA49B5.E02FA5E7@mvista.com>
On Thursdayen den 20 September 2001 21.55, george anzinger wrote:
> Roger Larsson wrote:
> > Hi,
> >
> > I ported my old latency-profiling patch to 2.4.10-pre10 with
> > the reschedulable kernel patch. (I have not checked that it is
> > preemption safe itself...)
> >
> > This patch works a little different from Robert Loves.
> > Since it samples the execution location at ticks.
> > It is possible to instrument an ordinary kernel too...
>
> It gives experienced latencies rather than potential latencies, but more
> important from the developer/maintainers point of view, "Robert Loves"
> patch provides information on the bad guys, i.e. the reason for the long
> latency, which, hopefully, will allow them to be addressed by competent
> maintainers.
>
Yes, but my technique can be applied to any kernel. It does not require
an preemptible kernel...
I.e. measures time from the moment a reschedulation was reqired to it
is actually done - independent of how it is done...
And if you run something that needs periodic reshedules you will detect
actual problems.
And thus it can be used as a bench, it is hard to describe skips in music,
textual data is easier to send by mail...
But I agree that Roberts is better to find the critical ones!
/RogerL
--
Roger Larsson
Skellefteå
Sweden
next prev parent reply other threads:[~2001-09-20 20:36 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-09-20 6:05 Roger Larsson
2001-09-20 19:55 ` george anzinger
2001-09-20 20:31 ` Roger Larsson [this message]
2001-09-20 20:17 ` Karim Yaghmour
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