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RE: Simple bash script is slow to execute - appears to be time spent starting commands like ls
- From: "David Tazartes" <davidt81 at earthlink dot net>
- To: "'Jeremy Bopp'" <jeremy at bopp dot net>, <cygwin at cygwin dot com>
- Date: Wed, 2 Sep 2009 14:45:30 -0400
- Subject: RE: Simple bash script is slow to execute - appears to be time spent starting commands like ls
Jeremy Bopp wrote:
How about we try to boil this down a little further? Try running the
following on your various systems and compare the results:
time for n in $(seq 1 10000); do true; done
I'm hopeful that this should help eliminate IO as a bottleneck in your
comparisons. Maybe someone else has a better suggestion.
If you still see a difference in performance of a similar magnitude as
you do with the echo | cut case, this might argue for fork being your
problem. I can't say whether or not what you're seeing is really
expected for fork though. All I know is that fork is fairly slow in
Cygwin. If it turns out that IO is the issue, I don't think I'll be
much help, not that I'm much help to begin with here. ;-)
It's also possible that you have BLODA on your laptop which could be
interfering in some way. I think cygcheck is able to identify some of
them for you. The problem reporting guidelines
(http://cygwin.com/problems.html) contain information for running
cygcheck which may help others identify typical problems.
-----
The true loop is only about 3 times slower on Cygwin than Linux. But: "true"
is a bash built-in, so there is no forking going on. So I'd argue this
absolutely shows there is a forking problem. ("time true" and "time echo hi"
both give all 0's.)
I also noticed that running "echo hi | c:\cygwin\bin\wc -l" just from cmd
seems to pause for a second or so. So perhaps I have just a problem starting
processes quickly in Vista.
cygcheck didn't reveal anything. I looked at the BLODA list and I only have
Symantec Antivirus as mentioned earlier, but I already tried disabling it to
no effect.
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