Subject: Re: libssh2 read performance. query..

Re: libssh2 read performance. query..

From: Kannamraju P via libssh2-devel <>
Date: Wed, 25 Oct 2017 11:42:01 -0400

I see some documentation online that some other client libraries like
openssh query these reads parallely and assemble them .
this gives better throughput I believe. Do we have something similar in


On Tue, Oct 24, 2017 at 11:54 AM, Daniel Stenberg <> wrote:

> On Tue, 24 Oct 2017, Kannamraju P wrote:
> It seems that the reads are done in sequential order , in networks which
>> have latency this slows down the read quite a bit.
> Yes of course they're sequential, since the API implies reading
> sequentially!
> And it is a work-around to *help* when you have long latencies, as I tried
> to explain as it allows the first responses to arrive earlier than
> otherwise. It is especially effective if you're reading more data in a loop
> (in a non-blocking fashion), and not just that single function call.
> SFTP is notoriously bad for long-latency connections (since each
> individual packet needs to be individually acked the in SFTP protocol
> layer). This approach is a way to try to make the effects of this less bad.
> Is there any workaround or configuration at library level or TCP level to
>> tune this.
> We've previously discussed adding some way to allow applications to tweak
> this behavior, and in particular the block sizes and read-ahead length
> libssh2 does, but we've never gotten around to actually do it.
> --
> /

thanks & Regards,

Received on 2017-10-25