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Date: Mon, 10 Dec 2007 14:28:02 +0100
From: Corinna Vinschen <corinna-cygwin AT cygwin DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: Updated: cygwin-1.5.25-5
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On Dec 10 10:57, Corinna Vinschen wrote:
> On Dec  9 10:49, Jim Reisert AD1C wrote:
> > I have a number of data processing programs written in C in the Cygwin
> > environment.  They read data files into linked lists, analyze the data
> > and write results back out to disk.
> >
> > This new release of Cygwin is about 10x slower than 1.5.24-2, after
> > recompiling the programs.  I went back to the older Cygwin release and
> > normal speed was restored.
> 
> Well, 10x sounds rather bad.

I can't reproduce worse I/O performance.  I tested different scenarios
with lots of disc I/O and the performance was identical between 1.5.24
and 1.5.25 within the bounds of a performance test.

In some cases applications are even getting faster under 1.5.25, for
instance cat(1) from coreutils.  This is likely due to the fact that
the st_blksize member in struct stat now returns 65536 (apparently the
preferred I/O blocksize in Windows).  This should also positively affect
the stdio functions like fread/fwrite.

Given the above, we really need a simple, self-contained testcase,
as I asked for in my previous mail on the subject.


Corinna


-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          cygwin AT cygwin DOT com
Red Hat

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