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: Wed, 13 Jun 2007 10:50:16 +0200 (CEST)

On Wed, 13 Jun 2007, Mononen Jussi wrote:

> "Acknowledgment" is a wrong word, sorry. Libssh2 blocks while it waits for
> response to a sent request. Command line tools do not have this limitation.
> They have their own "stack" implementation where they fire away tens of
> requests for data after first few successfull requests and they take care of
> the ordering of received responses based on TCP sequences. Thus the
> bandwidth is never unused as the requests and responses are fulfilling it to
> its capacity.

Ok thanks, I'm trying to understand this to see what can be done about this to
improve libssh2 performance.

What requests do libssh2 send that it waits for a response to that the openssh
tools don't? I'm looking at the code for a simple SCP download case, and I
don't see it.

Can you be a bit more specific and mention exact protocol details or perhaps
libssh2 source code functions/snippets that is the culprit of this mentioned

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Received on 2007-06-13