From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Michael Chan" <mchan@broadcom.com>
Subject: Re: Van Jacobson's net channels and real-time
Date: Mon, 24 Apr 2006 16:17:07 -0700
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Cc: "Auke Kok" <auke-jan.h.kok@intel.com>,
	"Ingo Oeser" <ioe-lkml@rameria.de>,
	"=?ISO-8859-1?Q?J=F6rn?= Engel" <joern@wohnheim.fh-wedel.de>,
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To: "linux-os (Dick Johnson)" <linux-os@analogic.com>
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On Mon, 2006-04-24 at 12:59 -0400, linux-os (Dick Johnson) wrote:

> Message signaled interrupts are just a kudge to save a trace on a
> PC board (read make junk cheaper still). They are not faster and
> may even be slower. They will not be the salvation of any interrupt
> latency problems.

MSI has 2 very nice properties: MSI is never shared and MSI guarantees
that all DMA activities before the MSI have completed. When you take
advantage of these guarantees in your MSI handler, there can be
noticeable improvements compared to using INTA.