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Date: Tue, 15 Jul 1997 01:02:10 -0700 (PDT)
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From: Simon Shapiro <Shimon@i-Connect.Net>
To: Steve Passe <smp@csn.net>
Subject: RE: interrupt latency
Cc: hackers@FreeBSD.ORG, smp@FreeBSD.ORG
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Hi Steve Passe;  On 14-Jul-97 you wrote: 
> Hi,
> 
> Can anyone recommend a test suite/methodology for evaluating interrupt
> latency?
> I have some ideas for improving the (currently poor) int response of the
> SMP
> kernel, but need a way to determine if I am actually bettering things.
> 
> --
> Steve Passe   | powered by
> smp@csn.net   |            Symmetric MultiProcessor FreeBSD
> 
>

I have microtime calls in the DPT driver.  If I understand it correctly, on
a P6-200 I could have 200 times better resolution with access to the
registers in the CPU.  I see interrupt latency of 0-3us with UP, and about
the same with SMP, but suspect the timers resolution at these low numbers.
Will be glad to acomodate.

Simon