From: Philippe Gerum <rpm@xenomai.org>
To: dietmar.schindler@manroland-web.com, Xenomai@xenomai.org
Subject: Re: [Xenomai] Message Pipe services behaviour
Date: Mon, 03 Nov 2014 10:08:01 +0100 [thread overview]
Message-ID: <545745F1.4070108@xenomai.org> (raw)
In-Reply-To: <208C6975C932E94F86239FEA59CCA632DCD4269B@AUSMXMBX02.mrws.biz>
On 11/03/2014 09:54 AM, dietmar.schindler@manroland-web.com wrote:
>> Von: Steve M. Robbins
>> Gesendet: Mittwoch, 29. Oktober 2014 17:11
>> ...
>> To avoid running through the select/read loop once for each message, our old
>> FIFO-based code opened the file in nonblocking mode and did a read into a buffer
>> that could hold up to 100 messages. We generally would read 5-7 at a time,
>> not 100, so this proved that the reader could keep up when reading in batches.
>>
>> Using this same technique with the /dev/rtpN end of a Message Pipe never reads
>> more than 1 message. I tried both blocking and non-blocking modes but got the
>> same result. So this is my main question: knowing that there are likely many
>> messages in the pipe, how do I read them in a batch?
>
> As far as I can see, read() from a Xenomai message pipe by design never returns more than one message at a time.
Clearly, but from the description, it seems like pulling all messages in
a loop from a non-blocking file descriptor only returns a single
message, although more messages are pending read, according to FIONREAD.
> --
> Regards,
> Dietmar Schindler
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--
Philippe.
prev parent reply other threads:[~2014-11-03 9:08 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-29 16:11 [Xenomai] Message Pipe services behaviour Steve M. Robbins
2014-10-29 17:30 ` Philippe Gerum
2014-10-31 20:00 ` Steve M. Robbins
2014-11-01 9:54 ` Philippe Gerum
2014-11-02 0:53 ` Steve M. Robbins
2014-11-03 8:18 ` Philippe Gerum
2014-11-03 15:59 ` Steve M. Robbins
2014-11-03 16:29 ` Philippe Gerum
2014-11-03 18:37 ` Steve M. Robbins
2014-11-03 20:01 ` Philippe Gerum
2014-11-03 20:03 ` Gilles Chanteperdrix
2014-11-03 20:18 ` Philippe Gerum
2014-11-03 22:22 ` Steve M. Robbins
2014-11-03 8:54 ` dietmar.schindler
2014-11-03 9:08 ` Philippe Gerum [this message]
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