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Date:      Fri, 8 Sep 2000 11:50:45 +1100 (EST)
From:      Bruce Evans <bde@zeta.org.au>
To:        Warner Losh <imp@village.org>
Cc:        The Hermit Hacker <scrappy@hub.org>, freebsd-current@FreeBSD.ORG, freebsd-smp@FreeBSD.ORG
Subject:   Re: 'interrupt-level buffer overflows' for sio device? 
Message-ID:  <Pine.BSF.4.21.0009081148120.30454-100000@besplex.bde.org>
In-Reply-To: <200009072129.PAA06098@harmony.village.org>

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On Thu, 7 Sep 2000, Warner Losh wrote:

> In message <Pine.BSF.4.21.0009062102140.572-100000@thelab.hub.org> The Hermit Hacker writes:
> : sio1: 32 more interrupt-level buffer overflows (total 32)
> 
> >From the man page:
>      sio%d: interrupt-level buffer overflow.  Problem in the bottom half of
>      the driver.
> 
> This likely means that the bottom half of sio isn't running fast
> enough to harvest the characters in the interrupt level buffers.

This means that fast interrupt handlers aren't actually fast.  Especially
if it occurs for slow devices like mouses.  Even slow interrupt handlers
had about 10 times lower latency than necessary for 1200 bps serial mouses.

Bruce



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