From: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
To: Peter Puchwein <peter.puchwein@domain.hid>
Cc: xenomai@xenomai.org
Subject: Re: [Xenomai-help] Negative Latency results
Date: Thu, 27 Aug 2009 13:14:45 +0200 [thread overview]
Message-ID: <4A966AA5.1050406@domain.hid> (raw)
In-Reply-To: <4A96692B.6070704@domain.hid>
Peter Puchwein wrote:
> Hi,
>
> what does a negative latency in the latency-test mean?
>
> RTH|-----lat min|-----lat avg|-----lat max|-overrun|----lat best|---lat
> worst
> RTD| -56.443| -54.519| -33.519| 0| -57.020|
> -28.208
It means that the timer handler ticked before the date it was supposed
to tick. This may have several causes:
- /proc/xenomai/latency is too high, adjust it
- hardware things stop the hardware counter used for timing, or slow it
down, such as cpufreq, acpi_processor or even the bios on x86.
--
Gilles
next prev parent reply other threads:[~2009-08-27 11:14 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-08-27 11:08 [Xenomai-help] Negative Latency results Peter Puchwein
2009-08-27 11:14 ` Gilles Chanteperdrix [this message]
2009-08-27 11:24 ` Peter Puchwein
2009-08-27 11:27 ` Gilles Chanteperdrix
2009-08-27 11:50 ` Christoph Permes
2009-08-27 12:05 ` Gilles Chanteperdrix
2009-08-27 12:33 ` Christoph Permes
2009-08-27 17:13 ` Gilles Chanteperdrix
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