Subject: Re: [libssh2] Speed and 'lockup'

Re: [libssh2] Speed and 'lockup'

From: Dan Fandrich <>
Date: Mon, 21 Jan 2008 10:30:08 -0800

On Mon, Jan 21, 2008 at 10:06:12AM -0500, Cary Fitzhugh wrote:
> We?ve noticed a slowdown of ~10x on downloading a file, as opposed to uploading
> a file. It seems that the discrepancy is in libssh2. openssh sftp puts and
> gets at about 7MB/s on our network. Libssh2 puts at around 6MB/s and gets at
> around 400kb/s. Does anyone know why this might be the case? I?m willing to
> look into it and do some work on the code if someone could point me in the
> right direction. Looked at ethereal captures, and seems like the packets are
> just 10x slower in being transmitted. I don?t see any broken packets or
> anything that looks out of the ordinary. To me at least.

This might be due to the fixed ssh window size problem that has been discussed
here before (last year probably). I'm not aware of anyone working on
the problem. Search the list archives to see what was discussed at the time.

>>> Dan

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Received on 2008-01-21