From: Ingo Molnar <mingo@elte.hu>
To: john stultz <johnstul@us.ibm.com>
Cc: John <me@privacy.net>,
linux-kernel@vger.kernel.org, tglx@timesys.com, akpm@osdl.org,
shill@free.fr
Subject: Re: One-shot high-resolution POSIX timer periodically late
Date: Wed, 24 Jan 2007 21:09:47 +0100 [thread overview]
Message-ID: <20070124200947.GA925@elte.hu> (raw)
In-Reply-To: <1169665347.6905.3.camel@localhost.localdomain>
* john stultz <johnstul@us.ibm.com> wrote:
> On Wed, 2007-01-24 at 10:41 +0100, John wrote:
> > I'm using the POSIX timers API. My platform is x86 running Linux
> > 2.6.18.6 patched with the high-resolution timer subsystem.
> >
> > http://www.tglx.de/hrtimers.html
> > My process is the only SCHED_FIFO process on the system. There are
> > no user-space processes with a higher priority. AFAICT, only a
> > kernel thread could keep the CPU away from my app.
> >
> > Is there a periodic kernel thread that runs every 2 seconds, cannot
> > be preempted, and runs for over 50 µs??
>
> This sounds like a BIOS SMI issue. Can you reproduce this behavior on
> different hardware?
note that only the -hrt patchset is used - not the full -rt patchset -
so 50 usecs delays (and more) are quite possible and common.
My question would be: does the same problem occur with the full -rt
patchset and PREEMPT_RT? (see http://rt.wiki.kernel.org for details)
Ingo
next prev parent reply other threads:[~2007-01-24 20:11 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <45B729AF.4030701@privacy.net>
2007-01-24 19:02 ` One-shot high-resolution POSIX timer periodically late john stultz
2007-01-24 20:09 ` Ingo Molnar [this message]
[not found] <fa.NwnlFyMPfa3XG6my3HKGWnCW3x4@ifi.uio.no>
[not found] ` <fa.Ji4GnAbBF2FR5JbSxvxn2haJZIk@ifi.uio.no>
2007-01-25 9:59 ` John
2007-01-25 22:19 ` john stultz
[not found] ` <fa.8TBiwbgs8B881k+3X+IlFjhqpLI@ifi.uio.no>
2007-01-25 12:03 ` John
[not found] <fa.mtUvfgenNQkCc8835prYbwyiPQs@ifi.uio.no>
[not found] ` <fa.lwkMc548uRMcUjd9KZ2pC1DMKT4@ifi.uio.no>
[not found] ` <fa.dTtI0ctv1nu+tCWiK6jGPnrX69k@ifi.uio.no>
[not found] ` <fa.CMU3scpnLxfHVWRFPcmfRl2CjhA@ifi.uio.no>
2007-01-30 17:38 ` John
2007-01-30 20:25 ` Ingo Molnar
[not found] <fa.4zD54Ie6Ozt0P4YqQSicS+XzXGw@ifi.uio.no>
[not found] ` <fa.G+/T32f2o1M3+YGLca/O8NaAQyY@ifi.uio.no>
[not found] ` <fa.6Ua8xjNfLKQEZZgDsoJgPMyww4g@ifi.uio.no>
[not found] ` <fa.yQlV+WU0TgrJTVqjopa01tgCnT0@ifi.uio.no>
[not found] ` <fa.ucVrLJ1Lh6FjdBHRglsIUc8/evk@ifi.uio.no>
[not found] ` <fa.Id9oufyELrVbe5Wb8SRakwC0V50@ifi.uio.no>
2007-02-01 10:18 ` John
2007-02-06 12:37 ` Ingo Molnar
2007-02-07 10:13 ` John
2007-02-05 16:37 ` John
2007-02-06 7:31 ` Peter Zijlstra
2007-02-07 10:25 ` John
2007-02-08 17:32 ` Thomas Gleixner
2007-02-09 15:25 ` John
2007-02-09 16:21 ` Benedikt Spranger
2007-02-09 16:43 ` Thomas Gleixner
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=20070124200947.GA925@elte.hu \
--to=mingo@elte.hu \
--cc=akpm@osdl.org \
--cc=johnstul@us.ibm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=me@privacy.net \
--cc=shill@free.fr \
--cc=tglx@timesys.com \
/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.