From: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
To: "Neil T. Dantam" <ntd@gatech.edu>
Cc: xenomai@xenomai.org
Subject: Re: [Xenomai] Slow Sockets and Pipes with POSIX Skin
Date: Mon, 21 Oct 2013 23:49:39 +0200 [thread overview]
Message-ID: <5265A173.4030608@xenomai.org> (raw)
In-Reply-To: <l44714$imt$1@ger.gmane.org>
On 10/21/2013 11:41 PM, Neil T. Dantam wrote:
> I am seeing some surprisingly high latencies for socket and pipe
> communication using Xenomai's POSIX skin. Pipes, localhost TCP/UDP,
> and local domain sockets all show worst case latency of ~100us on
> Xenomai 2.6.2.1/Linux 3.4.6 on a Xeon E3-1270v2. Average and 99%
> latency is under 20us. Running `xeno-test latency` gives worst-case
> latency of ~10us. POSIX message queues have worst case latency below
> 20us.
>
> I've done the following to reduce latency:
>
> * Disabled CPU frequency scaling
> * Disabled USB
> * Set real-time scheduling priority
> * Prefaulted the stack
>
> The 100us delay seems like what one get from a System Management
> Interrupt (SMI). However, since `xeno-test latency` and message
> queues both show low latency, it seems unlikely that this could be the
> issue.
>
> Has anyone else encountered (or not encountered) similar performance
> issues with pipes and sockets?
Xenomai posix skin does not handle pipes, and only handles TCP/IP
sockets if you have installed and configured rtnet.
--
Gilles.
prev parent reply other threads:[~2013-10-21 21:49 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-21 21:41 [Xenomai] Slow Sockets and Pipes with POSIX Skin Neil T. Dantam
2013-10-21 21:49 ` Gilles Chanteperdrix [this message]
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