Subject: Re: [libssh2] How to increase performance of libssh2 SFTP Read/Write

Re: [libssh2] How to increase performance of libssh2 SFTP Read/Write

From: Daniel Stenberg <>
Date: Thu, 14 Jun 2007 10:45:54 +0200 (CEST)

On Thu, 14 Jun 2007, Mononen Jussi wrote:

> We did some tests with libssh2-0.12 (with our own patch to change the 16
> byte read loop into 32kb read loop) and we came to a conclusion that libssh2
> is roughly 50% slower in file transfer than the command line counterparts.
> Eg. we had one test run where we transferred a 100MB file, command line scp
> took 58 seconds and libssh2 a bit over 2 minutes.

I think we should:

1 - do updated SCP measurements on current libssh2 CVS code and compare to
     recent openssh tools.

2 - work on making SCP perform roughly at the same speed as openssh - or more.
     We should do profiling etc to see where time is spent and where we should
     focus our efforts.

3 - measure SFTP performance (when large buffers are used by the client)

4 - adjust the SFTP API slightly and adapt code to improve SFTP performance

5 - smile

Now, all we need is lots of time...

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Received on 2007-06-14