From: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
To: "Beaufils Sylvie (IT&LAB)" <sylvie.beaufils@thomson-networks.com>
Cc: "xenomai@xenomai.org" <xenomai@xenomai.org>
Subject: Re: [Xenomai] Latency test results Xeon E5-1650 higher than Xeon E5620
Date: Sat, 15 Dec 2012 15:23:57 +0100 [thread overview]
Message-ID: <50CC87FD.70305@xenomai.org> (raw)
In-Reply-To: <14AA522E86E5754F8BC33C742D045A4A8134EFB4@srv0024.corp.thvnet.com>
On 12/11/2012 06:49 PM, Beaufils Sylvie (IT&LAB) wrote:
> I have read that "The most common reason for high latencies on x86
> are SMIs". But the SMI workaround does not manage the Patsburg LPC
> controller. I tried to add the PCI ID [8086:1d41] to
> ksrc/arch/x86/smi.c with this result: [ 1.926417] Xenomai:
> SMI-enabled chipset found [ 1.926490] Xenomai: SMI workaround
> failed!
>
> Should the SMI workaround be managed for the C602 chipset ? Could it
> explain the above latency results ?
Maybe, but as mentioned in the part of the troubleshooting guide you do
not quote, a "pathological" latency is a latency around say 100us.
The result of a latency test running:
- 1 minute
- on an idle system
is absolutely meaningless.
Anyway, if you want to understand the difference, you may use the I-pipe
tracer.
--
Gilles.
prev parent reply other threads:[~2012-12-15 14:23 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-11 17:49 [Xenomai] Latency test results Xeon E5-1650 higher than Xeon E5620 Beaufils Sylvie (IT&LAB)
2012-12-15 14:23 ` Gilles Chanteperdrix [this message]
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