cygwin performance problem

Damien Miller djm at
Fri Apr 21 07:47:03 EST 2006

On Thu, 20 Apr 2006, Corinna Vinschen wrote:

> However, while looking deeper into what's going on, it seems the bad
> results are somehow based on a strange interaction between ssh and scp,
> which triggers a performance problem in Cygwin.  Writing to the pipe to
> scp and reading from the pipe in scp seem to take a lot of time. 

Cygwin is set to use pipes instead of socketpairs for communication
between scp/sftp and ssh, and between sshd and its subprocesses. 
Perhaps you could try commenting out the

	AC_DEFINE(USE_PIPES, 1, [Use PIPES instead of a socketpair()])

line under the cygwin host case value in, or just deleting
the "#define USE_PIPES" from the generated config.h. If performance 
improves it might indicate a problem with Cygwin's pipe implementation.


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