From: Miroslav Lichvar <mlichvar@redhat.com>
To: John Stultz <john.stultz@linaro.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
"Nuno Gonçalves" <nunojpg@gmail.com>,
"Prarit Bhargava" <prarit@redhat.com>,
"Richard Cochran" <richardcochran@gmail.com>,
"Ingo Molnar" <mingo@kernel.org>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Shuah Khan" <shuahkh@osg.samsung.com>
Subject: Re: [PATCH 2/2][RFC] kselftest: timers: Add adjtick test to validate adjtimex() tick adjustments
Date: Wed, 9 Sep 2015 10:32:43 +0200 [thread overview]
Message-ID: <20150909083243.GN24711@localhost> (raw)
In-Reply-To: <1441778226-16538-2-git-send-email-john.stultz@linaro.org>
On Tue, Sep 08, 2015 at 10:57:06PM -0700, John Stultz wrote:
> Recently an issue was reported that was difficult to detect except
> by tweaking the adjtimex tick value, and noticing how quickly the
> adjustment took to be made:
> https://lkml.org/lkml/2015/9/1/488
>
> Thus this patch introduces a new test which manipulates the adjtimex
> tick value and validates the results are what we expect.
Great!
> + ppm = ((long long)tickval * MILLION)/10000 - MILLION;
I think this needs to be based on sysconf(_SC_CLK_TCK) or similar,
since the user-space HZ is not 100 on all archs.
> + for (tick = 9000; tick < 11000; tick += 250)
> + if (check_tick_adj(tick)) {
This too.
> + tx1.tick = 10000;
> + adjtimex(&tx1);
And this too.
--
Miroslav Lichvar
next prev parent reply other threads:[~2015-09-09 8:32 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-09 5:57 [PATCH 1/2][RFC] time: Fix timekeeping_freqadjust()'s incorrect use of abs() instead of abs64() John Stultz
2015-09-09 5:57 ` [PATCH 2/2][RFC] kselftest: timers: Add adjtick test to validate adjtimex() tick adjustments John Stultz
2015-09-09 8:32 ` Miroslav Lichvar [this message]
2015-09-09 17:10 ` John Stultz
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