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Message-Id: <5.1.0.14.2.20020605210753.02823c60@pop3.cris.com>
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Date: Wed, 05 Jun 2002 21:11:44 -0700
To: Russ Jorgensen <jorg928a AT yahoo DOT com>, cygwin AT cygwin DOT com
From: Randall R Schulz <rrschulz AT cris DOT com>
Subject: Re: Big Performance issue with CYGWIN 1.3.10 on Win2k - Urgent
  help reqd!
In-Reply-To: <20020606033103.40460.qmail@web21508.mail.yahoo.com>
References: <1022769047 DOT 11820 DOT ezmlm AT cygwin DOT com>
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Russ,

Something is amiss with your system or your installation.

Here's what I get running your scripts:

% time doit 1

real    0m0.972s
user    0m0.622s
sys     0m0.388s

% time doit 2

real    0m1.925s
user    0m1.513s
sys     0m0.828s

% set |egrep VER
BASH_VERSINFO=([0]="2" [1]="05a" [2]="0" [3]="3" [4]="release" 
[5]="i686-pc-cygwin")
BASH_VERSION='2.05a.0(3)-release'

% uname -a
CYGWIN_NT-5.0 CLEMENS 1.3.10(0.51/3/2) 2002-02-25 11:14 i686 unknown


It might be relevant that I have a dual-processor system.

Randall Schulz
Mountain View, CA USA



At 20:31 2002-06-05, Russ Jorgensen wrote:
>Was anyone able to resolve this issue?  A few weeks
>ago I posted about poor bash performance with "while
>read" loops.  Maybe this is the same issue...
>
>Anyway, I hadn't upgraded my cygwin1.dll for quite a
>long time, but when I did, some of my shell scripts
>started to have horrible performance.  I tracked it
>down to the "while read" loops.  I wrote the following
>benchmark shell script to see how bad the problem
>really is.  On my PII-333 running Win-ME, I get the
>following results:
>
># time ./doit 1
>
>real 0m3.555s
>user 0m0.000s
>sys  0m0.000s
>
># time ./doit 2
>
>real 0m22.870s
>user 0m0.000s
>sys  0m0.000s
>
>When I run the same benchmark on a linux machine, I
>don't get nearly as big a difference between the two
>runs.
>
>It would be really great if one of the crack
>programmers who work on cygwin could look into this.
>I imagine that everyone who uses cygwin would
>appreciate a performance boost!
>
>Anyway, here's the benchmark shell script.  Thanks.
>
>     -Russ
>
>#!/bin/bash
>
>#
># benchmark piping into "while read"
>#
># "doit 1" is the "first pass" which benchmarks
># generating output with the nested for-loops
>#
># "doit 2" is the "second pass" which adds on the
># "while read" loop
>#
>
># check usage
>if test $# -ne 1; then
>     echo "usage: doit {1|2}"
>     exit 1
>fi
>
># first pass: generate a bunch of output
>for i in 1 2 3 4 5 6 7 8 9 0; do
>     for j in 1 2 3 4 5 6 7 8 9 0; do
>         for k in 1 2 3 4 5 6 7 8 9 0; do
>             for l in 1 2 3 4 5 6 7 8 9 0; do
>                 echo hi
>             done
>         done
>     done
>done |
>
># second pass: the "while read" loop
>if test $1 != 2; then
>     cat - > /dev/null
>else
>     while read JUNK; do
>         A=1
>     done
>fi


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