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

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

From: Mononen Jussi <>
Date: Wed, 20 Jun 2007 09:10:21 +0300

>> > What about a comparison with openssh's sftp next to our
>> > sftp_nonblocking?
>> OpenSSH sftp: 0:01.06, 0:01.04, 0:01.01
>> libssh2 sftp_nonblock (libssh2 packet size:4K, sftp_nonblock
>> read 64K "static"): 0:01.60, 0:01.60, 0:01.58
>> That looks close enough to be called the same.


61 seconds (0:01:01) is not the same as 118 seconds (0:01:58). The
latter is ~100% slower. If this ratio endures when the file sizes grow
or the netowrk speed decreases the performance can be too weak. What if
OpenSSH sftp transfers one file in 10 minutes, libssh2 would take 20
minutes. From our/my point of view this is not acceptable and we/I have
had to rely on wrapping command line tools for certain performance
critical systems.

But I guess the packet pipelining is out of the scope of 0.15 release.



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Received on 2007-06-20