From: Philippe Gerum <rpm@xenomai.org>
To: CHABAL David <david.chabal@domain.hid>
Cc: xenomai@xenomai.org
Subject: Re: [Xenomai-help] awful latencies (~110us)
Date: Wed, 17 Oct 2007 17:24:33 +0200 [thread overview]
Message-ID: <1192634673.5973.33.camel@domain.hid> (raw)
In-Reply-To: <471621C8.9070006@domain.hid>
On Wed, 2007-10-17 at 16:52 +0200, CHABAL David wrote:
> >
> > Grmmff... I think the PIC on this box has some deep troubles; please try
> > this patch, in replacement of the previous ipipe_trace_special
> > instrumentation:
> >
>
>
> RTD| 8.348| 10.387| 43.647| 0| 6.098|
> 80.440
> ---|------------|------------|------------|--------|-------------------------
> RTS| 6.098| 10.020| 80.440| 0| 00:17:20/00:17:20
> [root@domain.hid bin]#
>
>
> IRQ handling takes 17µs in the worst case.
>
> It takes a long time to write 3 poor bytes...
>
Indeed. Each outb to the ISA bus should be somewhere in the 1-2.5 us
range depending on the hw, maybe a bit higher in case of contention, but
not that much.
> May be is it a SMI problem ??? (Globally disable SMI is on)
>
It's less likely with an ICH-2 chipset.
I see that CONFIG_IDEDMA_PCI_AUTO is disabled. Any reason not to use PCI
DMA when available for IDE drives with your hw?
--
Philippe.
next prev parent reply other threads:[~2007-10-17 15:24 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-05 7:52 [Xenomai-help] awful latencies (~110us) CHABAL David
2007-10-05 8:30 ` Gilles Chanteperdrix
2007-10-05 9:04 ` CHABAL David
2007-10-05 9:20 ` Philippe Gerum
2007-10-05 10:29 ` CHABAL David
2007-10-05 12:35 ` Jan Kiszka
2007-10-05 14:02 ` Philippe Gerum
2007-10-08 12:46 ` CHABAL David
2007-10-10 11:30 ` Philippe Gerum
2007-10-12 14:05 ` CHABAL David
2007-10-12 14:21 ` Jan Kiszka
2007-10-12 14:26 ` CHABAL David
2007-10-12 15:34 ` Philippe Gerum
2007-10-12 15:49 ` Jan Kiszka
2007-10-12 16:43 ` Philippe Gerum
2007-10-17 8:25 ` CHABAL David
2007-10-17 8:41 ` Philippe Gerum
2007-10-17 8:55 ` CHABAL David
2007-10-17 9:17 ` Philippe Gerum
2007-10-17 13:14 ` CHABAL David
2007-10-17 13:46 ` Philippe Gerum
2007-10-17 14:52 ` CHABAL David
2007-10-17 15:24 ` Philippe Gerum [this message]
2007-10-17 15:46 ` CHABAL David
2007-10-17 16:05 ` Philippe Gerum
2007-10-18 12:38 ` CHABAL David
2007-10-18 13:18 ` Philippe Gerum
2007-10-22 14:28 ` CHABAL David
2007-10-17 8:56 ` Philippe Gerum
2007-10-17 8:43 ` Philippe Gerum
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