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Message-ID: <01C0CF37.84F3E060.kern@sibbald.com>
From: Kern Sibbald <kern AT sibbald DOT com>
Reply-To: "kern AT sibbald DOT com" <kern AT sibbald DOT com>
To: "'cygwin AT cygwin DOT com'" <cygwin AT cygwin DOT com>
Subject: Cygwin 1.3.1 problems
Date: Fri, 27 Apr 2001 16:31:29 +0200
X-Mailer: Microsoft Internet E-mail/MAPI - 8.0.0.4211
Encoding: 78 TEXT

Hello,

I've been using cygwin for several years now and decided
to upgrade from 1.1.5 to 1.3.1, which I did today.  My main
reason for upgrading is to have the improved pthreads support
since 1.1.5 does not have pthread_cancel.

Unfortunately, my experience is not very positive due to a
dramatic reduction in the execution speed in 1.3.1.  Running
a ./configure command on a 400Mhz Linux system, and then
on a 400Mhz Win98 system with Cygwin 1.1.5, and finally
on the same 400Mhz Win98 system with Cygwin 1.3.1, I get
the following timings:

Linux RedHat 7.0 400MHz CPU 65Mb RAM
  real    0m23.861s
  user    0m17.730s
  sys     0m6.030s

Win98 with Cygwin 1.1.5 400Mhz CPU 256Mb RAM
  real    4m51.980s
  user    0m0.000s

Win98 with Cygwin 1.3.1 400MHz CPU 256Mb RAM
  real    29m16.570s
  user    0m0.000s
  sys     0m0.000s

The sad news is that Cygwin 1.3.1 is approximately
6 times slower than Cygwin 1.1.5. Already, Cygwin
1.1.5 suffered a major handicap compared to native
Linux in taking approximately 12 times as much time
to do the ./configure. Now with Cygwin 1.3.1 it
takes approximately 74 to 100 times as much time.

I can understand differences of 2 or maybe even 10,
but 74 times seems enormous.  

To test if the problem is in cygwin1.dll or in the
binary programs used (cat, sed, sh, ...), I dropped
the 1.3.1 cygwin1.dll into my 1.1.5 tree leaving
everything else unchanged and got the following 
timings:

real    34m23.440s
user    0m0.000s
sys     0m0.000s

Note, for the prior two executions, I rebooted to have
a perfectly clean environment. For this test, I ran
it after running the 1.1.5 test, and 1.1.5 always
consumes Win resources, thus it is not surprising
that the timing is a bit longer (34m23s 
compared to 29m16s).

My conclusion is that the 1.3.1 cygwin1.dll has
a serious performance problem.  I hope that someone
can take a look at this and provide a solution.  A bit
of performance tuning could accomplish some wonders
probably without a lot of work. 

I have been very happy with cygwin 1.1.5 even at 10-12
times slower than native Linux, but at 74-100 times slower,
it makes one wonder ...

Best regards,

Kern Sibbald
ch. Côtes-de-Montmoiret 9
CH-1012 Lausanne
Switzerland

Tel: +41 (21) 728-3411
Fax: +41 (21) 728-3459
Web: www.sibbald.com
Email: kern AT sibbald DOT com




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