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From: Magnus Holmgren <magnushol AT gmail DOT com>
Subject: Re: Cygwin slow on x64 systems
Date: Tue, 31 Aug 2010 20:34:45 +0000 (UTC)
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References: <4C7B9327 DOT 9030204 AT graphtech DOT co DOT il>
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Sagi Ben-Akiva <sagi <at> graphtech.co.il> writes:

> For the last couple of weeks I'm trying to identify the cause for cygwin 
> slowdown on x64 machines which was reported by David Morgan about 6 
> months ago.

<...>

> Any help will be appreciated.

I did some testing on my 64-bit Vista system, and it appears that 
CreateThread is the main cause. I added a few traces, and got this:

$ strace --mask=thread,sigp date
  149     149 [main] date 2944 cygthread::create: name ...
  159     308 [main] date 2944 cygthread::create: created name ...
 6241    6549 [main] date 2944 wait_for_sigthread: wait_sig_inited 0xB0
23606   30155 [sig] date 2944 cygthread::stub: cygthread::stub enter
  111   30266 [sig] date 2944 cygthread::stub: cygthread::stub callfunc
   65   30331 [sig] date 2944 cygthread::callfunc: wait for 'h'
   59   30390 [sig] date 2944 cygthread::callfunc: func
   65   30455 [sig] date 2944 init_sig_pipe: enter
 5343   35798 [sig] date 2944 init_sig_pipe: create pipe
  134   35932 [sig] date 2944 init_sig_pipe: exit
   72   36004 [sig] date 2944 wait_sig: entering ReadFile loop ...
    4   36008 [main] date 2944 wait_for_sigthread: process/signal ...

The second trace line is printed after CreateThread has returned, and the 
fourth line is the first thing executed in the new thread (don't know if it 
is a good idea to trace that early in the thread, but...).

  Magnus



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