From: Thomas Gleixner <tglx@linutronix.de>
To: Miroslav Lichvar <mlichvar@redhat.com>
Cc: John Stultz <jstultz@google.com>,
LKML <linux-kernel@vger.kernel.org>,
Stephen Boyd <sboyd@kernel.org>,
Anna-Maria Behnsen <anna-maria@linutronix.de>,
Frederic Weisbecker <frederic@kernel.org>,
Shuah Khan <shuah@kernel.org>,
linux-kselftest@vger.kernel.org, kernel-team@android.com,
Lei Chen <lei.chen@smartx.com>
Subject: Re: [PATCH v2 1/2] time/timekeeping: Fix possible inconsistencies in _COARSE clockids
Date: Thu, 03 Apr 2025 13:29:31 +0200 [thread overview]
Message-ID: <877c41wkis.ffs@tglx> (raw)
In-Reply-To: <Z-5HlSUEh1xgCi4f@localhost>
On Thu, Apr 03 2025 at 10:32, Miroslav Lichvar wrote:
> On Tue, Apr 01, 2025 at 08:29:23PM +0200, Thomas Gleixner wrote:
>> > 64 64 0.138
>>
>> That's weird as it only delays the update to the next tick.
>
> Ok, so it's not an instability of the clock, but rather an instability
> of the chronyd synchronization loop, which since kernel 4.19 expects
> the frequency to be applied as soon as the adjtimex call is finished.
Interesting.
>> Patch applies after reverting 757b000f7b93 ("timekeeping: Fix possible
>> inconsistencies in _COARSE clockids").
>
> I ran multiple longer tests to be able to compare the small values in
> the noise and yes, from the adjtimex point of view this seems to work
> as well as before the first COARSE fix. I didn't run any tests of the
> COARSE clock.
I did run those, but did not run the adjtimex() muck :)
next prev parent reply other threads:[~2025-04-03 11:29 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-20 20:03 [PATCH v2 1/2] time/timekeeping: Fix possible inconsistencies in _COARSE clockids John Stultz
2025-03-20 20:03 ` [PATCH v2 2/2] selftests/timers: Improve skew_consistency by testing with other clockids John Stultz
2025-03-25 11:32 ` [PATCH v2 1/2] time/timekeeping: Fix possible inconsistencies in _COARSE clockids Miroslav Lichvar
2025-03-27 9:22 ` Thomas Gleixner
2025-03-27 15:42 ` Miroslav Lichvar
2025-03-27 17:32 ` Thomas Gleixner
2025-03-31 7:53 ` Miroslav Lichvar
2025-04-17 2:55 ` John Stultz
2025-03-31 14:53 ` Miroslav Lichvar
2025-04-01 6:34 ` Thomas Gleixner
2025-04-01 11:19 ` Miroslav Lichvar
2025-04-01 18:29 ` Thomas Gleixner
2025-04-03 8:32 ` Miroslav Lichvar
2025-04-03 11:29 ` Thomas Gleixner [this message]
2025-04-05 21:40 ` [PATCH] timekeeping: Prevent coarse clocks going backwards Thomas Gleixner
2025-04-17 5:29 ` John Stultz
2025-04-17 12:36 ` Thomas Gleixner
2025-04-18 0:46 ` John Stultz
2025-04-18 6:37 ` Thomas Gleixner
2025-04-18 7:00 ` Thomas Gleixner
2025-04-19 5:55 ` John Stultz
2025-04-18 18:40 ` John Stultz
2025-04-19 5:46 ` [PATCH v3] " John Stultz
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