From: Cyril Hrubis <chrubis@suse.cz>
To: ltp@lists.linux.it
Subject: [LTP] [RFC] [PATCH] pselect01: Tune thresholds
Date: Fri, 12 May 2017 15:17:30 +0200 [thread overview]
Message-ID: <20170512131730.GA25149@rei.lan> (raw)
In-Reply-To: <trinity-29096542-6ccc-407c-b312-5b55c487a1f3-1494583440399@3capp-gmx-bs13>
Hi!
> Additionally, please keep in mind that on some architectures the
> time measured is based on the jiffies clock resolution which depends
> on the CONFIG_HZ value and results in a resolutions of e.g. 0.01,
> 0.004, or 0.001 seconds which is way above the resolution you get
> on the x86 platform (with the TSC clock).
>
> This testcase was failing for me on the parisc platform because of this inaccuracy.
>
> Maybe the resolution of the CLOCK_MONOTONIC clock (which is basically used in this
> test) should be checked with clock_getres() and it's result included in the calculation?
Right, I've dusted off old pxa270 and indeed we cannot measure less than
20us interval there. But clock_getres() returns 10ms which is much more
than the actuall measured value...
--
Cyril Hrubis
chrubis@suse.cz
next prev parent reply other threads:[~2017-05-12 13:17 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-05 13:18 [LTP] [RFC] [PATCH] pselect01: Tune thresholds Cyril Hrubis
2017-05-11 12:29 ` Cyril Hrubis
2017-05-11 15:54 ` Jan Stancek
2017-05-12 6:51 ` Cyril Hrubis
2017-05-12 7:11 ` Jan Stancek
2017-05-12 7:17 ` Cyril Hrubis
2017-05-12 7:33 ` Jan Stancek
2017-05-12 10:04 ` Helge Deller
2017-05-12 13:17 ` Cyril Hrubis [this message]
2017-05-12 13:59 ` Cyril Hrubis
2017-05-12 15:38 ` Cyril Hrubis
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