Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm
List-Subscribe: <mailto:cygwin-subscribe AT cygwin DOT com>
List-Archive: <http://sources.redhat.com/ml/cygwin/>
List-Post: <mailto:cygwin AT cygwin DOT com>
List-Help: <mailto:cygwin-help AT cygwin DOT com>, <http://sources.redhat.com/ml/#faqs>
Sender: cygwin-owner AT cygwin DOT com
Mail-Followup-To: cygwin AT cygwin DOT com
Delivered-To: mailing list cygwin AT cygwin DOT com
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>
Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature";
	boundary="=-uPqlegiaJ8mInDq9qOW8"
Date: 30 Nov 2002 00:08:34 +1100
Message-Id: <1038575316.4126.7.camel@lifelesswks>
Mime-Version: 1.0

--=-uPqlegiaJ8mInDq9qOW8
Content-Type: text/plain
Content-Transfer-Encoding: quoted-printable

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
--=20
---
GPG key available at: http://users.bigpond.net.au/robertc/keys.txt.
---

--=-uPqlegiaJ8mInDq9qOW8
Content-Type: application/pgp-signature; name=signature.asc
Content-Description: This is a digitally signed message part

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.0.7 (GNU/Linux)

iD8DBQA952bSI5+kQ8LJcoIRAp4BAKCSyS+Q4mEXqowNC+oRMoD0ow4yIgCgw5O/
G+g5g78D9Ck6nL7WImPRfbU=
=7e5X
-----END PGP SIGNATURE-----

--=-uPqlegiaJ8mInDq9qOW8--