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From: Richard Cochran <richardcochran@gmail.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>,
	Ingo Molnar <mingo@kernel.org>,
	lkml <linux-kernel@vger.kernel.org>,
	Prarit Bhargava <prarit@redhat.com>,
	Daniel Bristot de Oliveira <bristot@redhat.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: [RFC][PATCH 4/4] time: Do leapsecond adjustment in gettime fastpaths
Date: Fri, 5 Jun 2015 16:12:59 +0200	[thread overview]
Message-ID: <20150605141259.GA9406@localhost.localdomain> (raw)
In-Reply-To: <1433495408.1495.8.camel@twins>

On Fri, Jun 05, 2015 at 11:10:08AM +0200, Peter Zijlstra wrote:
> Firstly I would strongly suggest such applications not use UTC because
> of this, I think TAI was invented for just this reason.

So I wonder whether the bug in the original post affects TAI timers as
well...

> Secondly, how would John's patches help with this? Usespace loops
> reading time would be using the VDSO and would still not get the right
> time, and timers would be subject to the same IRQ latency that a hrtimer
> based leap second insert would, and would still very much not be in-sync
> across the cluster.

But we have a tick based insertion.  (IIRC, it used to be hrtimer
based, but that was buggy, too).

Thanks,
Richard

  reply	other threads:[~2015-06-05 14:13 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-05-29 20:24 [RFC][PATCH 0/4] Fixes for leapsecond expiring early ABS_TIME CLOCK_REALTIME timers John Stultz
2015-05-29 20:24 ` [RFC][PATCH 1/4] selftests: timers: Add leap-second timer edge testing to leap-a-day.c John Stultz
2015-05-29 20:24 ` [RFC][PATCH 2/4] timer_list: Add the base offset so remaining nsecs are accurate for non monotonic timers John Stultz
2015-05-29 20:24 ` [RFC][PATCH 3/4] ntp: Use printk_deferred in leapsecond path John Stultz
2015-06-02 10:31   ` Jiri Bohac
2015-06-02 10:43     ` Jiri Kosina
2015-06-02 16:14       ` John Stultz
2015-06-02 16:04     ` John Stultz
2015-05-29 20:24 ` [RFC][PATCH 4/4] time: Do leapsecond adjustment in gettime fastpaths John Stultz
2015-05-31 16:05   ` Richard Cochran
2015-06-02  9:01   ` Ingo Molnar
2015-06-02  9:21     ` Peter Zijlstra
2015-06-02 14:09       ` John Stultz
2015-06-02 15:52     ` John Stultz
2015-06-03  9:04       ` Ingo Molnar
2015-06-03 17:44         ` John Stultz
2015-06-04  6:48           ` Ingo Molnar
2015-06-05  0:08             ` John Stultz
2015-06-05  7:29               ` Peter Zijlstra
2015-06-05  9:04                 ` Richard Cochran
2015-06-05  9:10                   ` Peter Zijlstra
2015-06-05 14:12                     ` Richard Cochran [this message]
2015-06-05 17:28                       ` John Stultz
2015-06-06  9:44                     ` Thomas Gleixner
2015-06-08 17:55                       ` John Stultz
2015-06-08 19:05                         ` Thomas Gleixner
2015-06-08 20:02                           ` Thomas Gleixner
2015-06-05 11:37                   ` Prarit Bhargava
2015-06-05 12:07                     ` Thomas Gleixner
2015-06-05 14:22                 ` Richard Cochran
2015-06-05 17:24                 ` John Stultz
2015-05-31 13:55 ` [RFC][PATCH 0/4] Fixes for leapsecond expiring early ABS_TIME CLOCK_REALTIME timers Prarit Bhargava
2015-06-01 11:57 ` Prarit Bhargava
2015-06-01 17:02   ` John Stultz
2015-06-01 17:43     ` Prarit Bhargava
2015-06-01 20:18 ` Daniel Bristot de Oliveira
2015-06-01 20:32   ` John Stultz
2015-06-01 21:42   ` Prarit Bhargava
2015-06-01 22:29     ` Daniel Bristot de Oliveira
2015-06-02  6:19       ` John Stultz

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