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To: Greg Lehey <grog@lemis.com>
Subject: Re: Tidying up the interrupt registration process 
Cc: arch@FreeBSD.ORG, smp@FreeBSD.ORG
In-reply-to: Your message of "Wed, 19 Jul 2000 13:09:07 +0930."
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Date: Tue, 18 Jul 2000 23:58:43 -0600
From: Warner Losh <imp@village.org>
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In message <20000719130907.H12072@wantadilla.lemis.com> Greg Lehey writes:
: I think this function needs to be completely rewritten in the course
: of the implementation of interrupt threads.  It sort of works now, so
: I don't think we should touch it further until the threads are up and
: hobbling.

I want to fix the fast interrupt part of it.

: That's what I thought.  Does anybody else see a reason to convert fast
: interrupts into threads?

So long as they run with the lowest possible latency, that would be
OK.

: > pci modems are an interesting problem.  You want to share an
: > interrupt, but fast interrupts can't be shared.  On sufficiently
: > fast machines, it isn't an issue, but on slow machines you can
: > easily lose characters because interrupts are masked for too long.
: > Heavy VM load (eg swapping) seems to make this problem happen more
: > often than even just simple heavy disk I/O, but I've not done
: > extensive tests to draw boundaries around this problem.
: 
: I can't see anything inherent in the treatment of fast interrupts
: which says they can't be shared.  I'll take another look at the code;
: maybe we can get rid of this restriction.

I think it is an implementation thing, but bde will know better.

Warner


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