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Subject:	Re: pipe performance problem
From:	Robert Collins <rbcollins AT cygwin DOT com>
To:	cygwin AT cygwin DOT com
In-Reply-To:	<20021129020012.GB9074@redhat.com>
References:	<14936170000 DOT 20021127223905 AT huno DOT net>
	<20021127233624 DOT GK17798 AT redhat DOT com> <1245871093 DOT 20021128012046 AT huno DOT net>
	<20021128003443 DOT GD21457 AT redhat DOT com> <5549457171 DOT 20021128022032 AT huno DOT net>
	<6654089625 DOT 20021128033745 AT huno DOT net> <1988826218 DOT 20021128150740 AT huno DOT net>
	<14015247140 DOT 20021129012600 AT huno DOT net> <20021129003838 DOT GA8794 AT redhat DOT com>
	<10718265421 DOT 20021129021618 AT huno DOT net> <20021129020012 DOT GB9074 AT redhat DOT com>
Date:	30 Nov 2002 00:08:34 +1100
Message-Id:	<1038575316.4126.7.camel@lifelesswks>
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On Fri, 2002-11-29 at 13:00, Christopher Faylor wrote:

> Of course, it is entirely possible that there is something wrong with
> the logic in cygwin and that a pipe is waiting 10ms for every read or
> something like that.  I don't know.  I don't see how that's possible
> from the code in ready_for_read but it's certainly at least a
> possibility.

My WAG is that this is happening:

because dd has higher scheduler priority, it interrupts mkisofs every
10ms, and on average hits the 10ms sleep every second read.

Rob
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