From: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
To: "Jens Köhler" <jenskxxx@domain.hid>
Cc: xenomai@xenomai.org
Subject: Re: [Xenomai-help] Xenomai and select() function - don't work correctly
Date: Fri, 18 Mar 2011 12:53:08 +0100 [thread overview]
Message-ID: <4D8347A4.7080303@domain.hid> (raw)
In-Reply-To: <AANLkTi=G7sEYAqMKS+PEaDgH2q=d-h=_wsoCkFZLLAip@domain.hid>
Jens Köhler wrote:
> Hello,
>
> on my atom processor based computer is Xenomai installed. (Kernel 2.6.26,
> 1000Hz, Xenomai 2.4.10, PREEMPT patch, no xenomai application running).
>
> A normal linux application reads serial data from an UART
> (16550A) and checks by select() function if there are new received
> bytes. Select() has a timeout parameter, set to 12 milliseconds. Some times
> it happens that select() waits 43 ms instead of maximum 12 ms. Result value
> of select() is timeout instead of "byte received". Could this caused by
> Xenomai?
Run the same test without enabling Xenomai in the kernel configuration,
and you will know.
> How could I improve it?
Well basically, you are complaining that Linux is not real-time. We know
that, this is the reason why real-time extensions such as Xenomai or
preempt_rt exist.
--
Gilles.
next prev parent reply other threads:[~2011-03-18 11:53 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-18 11:48 [Xenomai-help] Xenomai and select() function - don't work correctly Jens Köhler
2011-03-18 11:53 ` Gilles Chanteperdrix [this message]
2011-03-18 12:05 ` Jan Kiszka
2011-03-18 14:05 ` Jens Köhler
2011-03-18 22:12 ` Gilles Chanteperdrix
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