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To: Luigi Rizzo <rizzo@icir.org>
From: "Poul-Henning Kamp" <phk@phk.freebsd.dk>
In-Reply-To: Your message of "Thu, 25 Dec 2003 10:25:49 PST."
             <20031225102549.A79161@xorpc.icir.org> 
Date: Thu, 25 Dec 2003 19:41:20 +0100
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cc: Robert Watson <rwatson@freebsd.org>
cc: Ian Smith <smithi@nimnet.asn.au>
cc: soekris-tech@lists.soekris.com
cc: timg@tpi.com
cc: net@freebsd.org
Subject: Re: [Soekris] Re: bridge with access on both interfaces 
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In message <20031225102549.A79161@xorpc.icir.org>, Luigi Rizzo writes:

>If you have shared interrupts, and one of the interfaces is not up, you
>end up doing a lot of useless calls to sis_stop(), which is terribly
>expensive (it even includes a DELAY(1000) call).
>At the very least, one should add a 'stopped' flag so that
>sis_stop() is only called when necessary -- or possibly even
>never at all.
>
>The second (minor) cause of performance loss are the calls
>(not shown above)
>to disable and re-enable the interrupts around the driver. These are
>completely useless, yet cause some extra PCI transactions.

I don't know if it is correct, but at the very least I have thought
the same thoughts when I looked at the driver last, but I didn't
get time to try out the idea...

Somebody with some spare time should look at this...

Poul-Henning

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.