From: Prarit Bhargava <prarit@redhat.com>
To: John Stultz <john.stultz@linaro.org>
Cc: linux-kernel@vger.kernel.org,
Daniel Bristot de Oliveira <bristot@redhat.com>,
Richard Cochran <richardcochran@gmail.com>,
Jan Kara <jack@suse.cz>, Jiri Bohac <jbohac@suse.cz>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
Shuah Khan <shuahkh@osg.samsung.com>
Subject: Re: [PATCH 0/5 v2] Fixes for leapsecond expiring early ABS_TIME CLOCK_REALTIME timers
Date: Mon, 15 Jun 2015 09:46:40 -0400 [thread overview]
Message-ID: <557ED740.7030000@redhat.com> (raw)
In-Reply-To: <557ECEB8.6010804@redhat.com>
On 06/15/2015 09:10 AM, Prarit Bhargava wrote:
>
>
> On 06/11/2015 06:54 PM, John Stultz wrote:
>> So this is a second round at trying to address the issue, trying
>> to integrate feedback from Ingo and Thomas, trying to simplify
>> what I can. I've also split out the changes so each can be
>> more easily reviewed. Its still not tiny, but its simpler.
>>
>> This series is against tip/timers/core, and the first patch isn't
>> strictly related but is a fix that is needed in tip/timers/core.
>>
>> As Prarit reported here:
>> https://lkml.org/lkml/2015/5/27/458
>>
>> Since the leapsecond is applied at timer tick time, and not
>> the actual second edge, ABS_TIME CLOCK_REALTIME timers set for
>> right after the leapsecond could fire a second early, since
>> some timers may be expired before we trigger the timekeeping
>> timer, which then applies the leapsecond.
>>
>> Thus this patch series tries to address this issue, including
>> extending the leap-a-day test to catch this problem, as well
>> as other relevant fixups I found while working on the code.
>>
>> This series has only had limited testing, so I wanted to send
>> it out for initial review and comment. Folks can grab this tree
>> via git for testing here:
>> https://git.linaro.org/people/john.stultz/linux.git dev/early-leap-timer
>>
>
> I'm testing this on a few more large CPU count systems. So far, so good ...
>
John, unfortunately I'm seeing failures across a lot of the large systems
dev/early-leap-timer as of this AM
[root@intel-chiefriver-04 ~]# systemctl status chronyd
chronyd.service - NTP client/server
Loaded: loaded (/usr/lib/systemd/system/chronyd.service; enabled)
Active: inactive (dead) since Mon 2015-06-15 09:25:33 EDT; 5s ago
Process: 731 ExecStartPost=/usr/libexec/chrony-helper add-dhclient-servers
(code=exited, status=0/SUCCESS)
Process: 713 ExecStart=/usr/sbin/chronyd -u chrony $OPTIONS (code=exited,
status=0/SUCCESS)
Main PID: 724 (code=exited, status=0/SUCCESS)
CGroup: /system.slice/chronyd.service
Jun 15 09:25:06 intel-chiefriver-04.khw.lab.eng.bos.redhat.com chronyd[724]: ...
Jun 15 09:25:06 intel-chiefriver-04.khw.lab.eng.bos.redhat.com chronyd[724]: ...
Jun 15 09:25:06 intel-chiefriver-04.khw.lab.eng.bos.redhat.com chronyd[724]: ...
Jun 15 09:25:06 intel-chiefriver-04.khw.lab.eng.bos.redhat.com chronyd[724]: ...
Jun 15 09:25:06 intel-chiefriver-04.khw.lab.eng.bos.redhat.com systemd[1]: St...
Jun 15 09:25:19 intel-chiefriver-04.khw.lab.eng.bos.redhat.com chronyd[724]: ...
Jun 15 09:25:19 intel-chiefriver-04.khw.lab.eng.bos.redhat.com chronyd[724]: ...
Jun 15 09:25:33 intel-chiefriver-04.khw.lab.eng.bos.redhat.com systemd[1]: St...
Jun 15 09:25:33 intel-chiefriver-04.khw.lab.eng.bos.redhat.com chronyd[724]: ...
Jun 15 09:25:33 intel-chiefriver-04.khw.lab.eng.bos.redhat.com systemd[1]: St...
Hint: Some lines were ellipsized, use -l to show in full.
[root@intel-chiefriver-04 ~]# ./leap-a-day -s
Setting time to speed up testing
This runs continuously. Press ctrl-c to stop
Setting time to Mon Jun 15 19:59:50 2015
Scheduling leap second for Mon Jun 15 20:00:00 2015
Setting timer for Mon Jun 15 20:00:00 2015
Mon Jun 15 19:59:57 2015 + 18177 us (0) TIME_INS
Mon Jun 15 19:59:57 2015 + 526181 us (0) TIME_INS
Mon Jun 15 19:59:58 2015 + 37418 us (0) TIME_INS
Mon Jun 15 19:59:58 2015 + 546474 us (0) TIME_INS
Mon Jun 15 19:59:59 2015 + 55724 us (0) TIME_INS
Mon Jun 15 19:59:59 2015 + 566970 us (0) TIME_INS
Mon Jun 15 19:59:59 2015 + 6013 us (1) TIME_OOP - TIMER FIRED
Error: Early timer expiration!
Error: Incorrect NTP state?
Mon Jun 15 19:59:59 2015 + 6040 us (1) TIME_OOP
Mon Jun 15 19:59:59 2015 + 517240 us (1) TIME_OOP
Mon Jun 15 20:00:00 2015 + 28504 us (1) TIME_WAIT
Mon Jun 15 20:00:00 2015 + 539745 us (1) TIME_WAIT
Mon Jun 15 20:00:01 2015 + 50978 us (1) TIME_WAIT
Mon Jun 15 20:00:01 2015 + 560360 us (1) TIME_WAIT
Mon Jun 15 20:00:02 2015 + 69952 us (1) TIME_WAIT
ERROR: hrtimer early expiration failure observed.
Leap complete
Errors observed
P.
next prev parent reply other threads:[~2015-06-15 13:46 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-11 22:54 John Stultz
2015-06-11 22:54 ` [PATCH 1/5] time: Move clock_was_set_seq update to before we update the shadow-timekeeper John Stultz
2015-06-12 9:31 ` [tip:timers/core] time: Move clock_was_set_seq update before updating shadow-timekeeper tip-bot for John Stultz
2015-06-11 22:54 ` [PATCH 2/5] ntp: Introduce and use SECS_PER_DAY macro instead of 86400 John Stultz
2015-06-12 9:31 ` [tip:timers/core] " tip-bot for John Stultz
2015-06-11 22:54 ` [PATCH 3/5] time: Do leapsecond adjustment to avoid early timer expirations John Stultz
2015-06-12 9:32 ` [tip:timers/core] time: Prevent early expiry of hrtimers[ CLOCK_REALTIME] at the leap second edge tip-bot for John Stultz
2015-06-11 22:54 ` [PATCH 4/5] ntp: Do leapsecond adjustment in adjtimex read path John Stultz
2015-06-12 7:37 ` Richard Cochran
2015-06-12 9:32 ` [tip:timers/core] " tip-bot for John Stultz
2015-06-11 22:54 ` [PATCH 5/5] selftests: timers: Add leap-second timer edge testing to leap-a-day.c John Stultz
2015-06-12 9:32 ` [tip:timers/core] " tip-bot for John Stultz
2015-06-12 14:52 ` [PATCH 0/5 v2] Fixes for leapsecond expiring early ABS_TIME CLOCK_REALTIME timers Dave Jones
2015-06-12 14:55 ` Prarit Bhargava
2015-06-12 14:59 ` Dave Jones
2015-06-12 15:02 ` Prarit Bhargava
2015-06-12 17:58 ` John Stultz
2015-06-12 18:06 ` John Stultz
2015-06-12 18:11 ` Thomas Gleixner
2015-06-13 7:17 ` Ingo Molnar
2015-06-15 13:10 ` Prarit Bhargava
2015-06-15 13:46 ` Prarit Bhargava [this message]
2015-06-15 18:55 ` John Stultz
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