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Re: Big Performance issue with CYGWIN 1.3.10 on Win2k - Urgent help reqd!


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")

% 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

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.



# 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

# 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 |

# second pass: the "while read" loop
if test $1 != 2; then
    cat - > /dev/null
    while read JUNK; do

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