From: Helge Deller <deller@gmx.de>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Linux Kernel Development <linux-kernel@vger.kernel.org>,
linux-parisc <linux-parisc@vger.kernel.org>
Subject: timerfd_settime/timerfd_gettime issue ?
Date: Sat, 26 Dec 2015 13:26:14 +0100 [thread overview]
Message-ID: <567E8766.6020707@gmx.de> (raw)
Hi Thomas,
I see a strange behavior on the parisc platform, for which I'm not sure if it's intended or
if there is a bug somewhere.
The program calls timerfd_settime() and sets a timer (e.g. sec=0, nsec=100000000).
Directly after setting the timer it calls timerfd_gettime() and receives (sec=0, nsec=103914413).
The second nsec is higher than the initial nsec value which was set.
Does timerfd_settime() maybe tries to add the initial time it takes to start the timer?
Any idea or hint?
Thanks,
Helge
Background:
I'm debugging the build-failure on debian for the liblinux-fd-perl package:
https://buildd.debian.org/status/fetch.php?pkg=liblinux-fd-perl&arch=hppa&ver=0.011-1&stamp=1443355593
Here is a log which I get from kernel after adding some printks.
The problematic line is #3.
[ 465.888000] timerfd_settime: interval (sec=0, nsec=0) it_value (sec=0, nsec=100000000)
[ 466.196000] timerfd_settime: interval (sec=0, nsec=100000000) it_value (sec=0, nsec=100000000)
[ 466.300000] timerfd_gettime: interval (sec=0, nsec=100000000) it_value (sec=0, nsec=103914413)
[ 466.404000] timerfd_gettime: interval (sec=0, nsec=100000000) it_value (sec=0, nsec=97444552)
[ 466.508000] timerfd_gettime: interval (sec=0, nsec=100000000) it_value (sec=0, nsec=92611704)
[ 466.616000] timerfd_gettime: interval (sec=0, nsec=100000000) it_value (sec=0, nsec=87376859)
[ 466.720000] timerfd_gettime: interval (sec=0, nsec=100000000) it_value (sec=0, nsec=82538534)
[ 466.824000] timerfd_gettime: interval (sec=0, nsec=100000000) it_value (sec=0, nsec=77293289)
[ 466.928000] timerfd_gettime: interval (sec=0, nsec=100000000) it_value (sec=0, nsec=72501584)
[ 467.036000] timerfd_gettime: interval (sec=0, nsec=100000000) it_value (sec=0, nsec=67377673)
[ 467.140000] timerfd_gettime: interval (sec=0, nsec=100000000) it_value (sec=0, nsec=62631601)
[ 467.244000] timerfd_gettime: interval (sec=0, nsec=100000000) it_value (sec=0, nsec=57401824)
next reply other threads:[~2015-12-26 12:26 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-26 12:26 Helge Deller [this message]
2015-12-29 9:44 ` timerfd_settime/timerfd_gettime issue ? Thomas Gleixner
2015-12-29 20:13 ` Helge Deller
2015-12-30 9:57 ` Thomas Gleixner
2016-01-04 22:27 ` Helge Deller
2016-01-10 20:57 ` [PATCH parisc,frv,m68k] timerfd: Fix timeout values with CONFIG_TIME_LOW_RES=y Helge Deller
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=567E8766.6020707@gmx.de \
--to=deller@gmx.de \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-parisc@vger.kernel.org \
--cc=tglx@linutronix.de \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox