From: William Lee Irwin III <wli@holomorphy.com>
To: Robert Love <rml@tech9.net>
Cc: Chris Friesen <cfriesen@nortelnetworks.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: how to measure scheduler latency on powerpc? realfeel doesn't work due to /dev/rtc issues
Date: Fri, 9 May 2003 09:53:59 -0700 [thread overview]
Message-ID: <20030509165359.GX8978@holomorphy.com> (raw)
In-Reply-To: <1052498824.867.8.camel@icbm>
On Fri, 2003-05-09 at 03:01, William Lee Irwin III wrote:
>> Why not just keep track of it in the scheduler? The statistic is well-
>> defined in terms of things measurable at context switch and wakeup.
On Fri, May 09, 2003 at 12:47:05PM -0400, Robert Love wrote:
> This would measure context switch latency. Or something.
> By definition, scheduling latency is the time from an interrupt which
> wakes the task up until the task is actually running.
> Historically, it has been measured by things like realfeel or amlat or
> whatever which generate interrupts and wake a waiting task up. You then
> measure the latency between the interrupt and when the task actually
> runs in user-space.
> So Chris can then go run this test under varying loads and see how bad
> the latency gets. I understand his question, but (sorry Chris) I have
> no idea of the solution on PPC.
Not at all. Just stamp at wakeup and difference when it runs.
-- wli
next prev parent reply other threads:[~2003-05-09 16:42 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-05-08 22:12 how to measure scheduler latency on powerpc? realfeel doesn't work due to /dev/rtc issues Chris Friesen
2003-05-09 0:13 ` William Lee Irwin III
2003-05-09 0:38 ` Davide Libenzi
2003-05-09 0:38 ` William Lee Irwin III
2003-05-09 0:56 ` Richard B. Johnson
2003-05-09 3:52 ` Chris Friesen
2003-05-09 4:13 ` Roland Dreier
2003-05-09 6:07 ` Chris Friesen
2003-05-09 4:26 ` William Lee Irwin III
2003-05-09 6:14 ` Chris Friesen
2003-05-09 6:20 ` William Lee Irwin III
2003-05-09 6:53 ` Chris Friesen
2003-05-09 7:01 ` William Lee Irwin III
2003-05-09 16:47 ` Robert Love
2003-05-09 16:53 ` William Lee Irwin III [this message]
2003-05-09 17:38 ` Chris Friesen
2003-05-09 11:37 ` paubert
2003-05-09 8:23 ` mikpe
2003-05-09 8:17 ` how to measure scheduler latency on powerpc? realfeel doesn Giuliano Pochini
-- strict thread matches above, loose matches on Subject: below --
2003-05-10 0:39 how to measure scheduler latency on powerpc? realfeel doesn' t work due to /dev/rtc issues Perez-Gonzalez, Inaky
2003-05-12 23:55 ` William Lee Irwin III
[not found] <493798056@toto.iv>
2003-05-12 5:04 ` how to measure scheduler latency on powerpc? realfeel doesn't " Peter Chubb
2003-05-12 5:08 ` William Lee Irwin III
2003-05-13 0:20 how to measure scheduler latency on powerpc? realfeel doesn' t " Perez-Gonzalez, Inaky
2003-05-13 1:02 ` William Lee Irwin III
2003-05-13 2:08 Perez-Gonzalez, Inaky
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20030509165359.GX8978@holomorphy.com \
--to=wli@holomorphy.com \
--cc=cfriesen@nortelnetworks.com \
--cc=linux-kernel@vger.kernel.org \
--cc=rml@tech9.net \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.