Subject: Re: [libssh2] libssh2-0.16 hanging on scp copy

Re: [libssh2] libssh2-0.16 hanging on scp copy

From: Daniel Stenberg <>
Date: Sun, 12 Aug 2007 23:56:21 +0200 (CEST)

On Tue, 7 Aug 2007, Peter O'Gorman wrote:

> Tried to copy it to x86_64 redhat enterprise linux 4, and it always hangs
> before finishing the copy.

I've just now committed my second fix for this problem, and I can now
repeatedly transfer an 840MB file over SCP using the scp_nonblock example.

The libssh2_channel_receive_window_adjust() function missed to set the state
variables at times and thus this function would misbehave on repeated invokes.

BTW, while working on this I did a quick performance test for
scp_nonblock/libssh2 versus scp/openssh and this file sent over localhost
takes 27.6 seconds for libssh2 but only 19.2 seconds for openssh... it makes
libssh2 ~40% slower! (and I used a 65000 bytes buffer in the example code)

It wouldn't surprise me if the window size code in libssh2 can be improved

I also found another flaw that I'll post about in a separate thread coming
right up.

This email is sponsored by: Splunk Inc.
Still grepping through log files to find problems? Stop.
Now Search log events and configuration files using AJAX and a browser.
Download your FREE copy of Splunk now >>
libssh2-devel mailing list
Received on 2007-08-12