Subject: Re: Slow SFTP uploads; failure if compression enabled

Re: Slow SFTP uploads; failure if compression enabled

From: Daniel Stenberg <>
Date: Fri, 22 Oct 2010 09:20:18 +0200 (CEST)

On Thu, 21 Oct 2010, Mark Riordan wrote:

> First, upload performance is slow, especially on Windows.

This is known and has been discussed several times. I have added comments to
the TODO file about ideas I have to improve things, but afaik I am the only
one (slowly) working on this so don't expect any sudden changes.

> Secondly, uploads don't work at all if I enable compression.

Exactly what I found out yesterday:

> Without compression, uploads succeed, but performance is horrible on Windows
> Here's a table of performance.

Gosh! Those are really terrible numbers. Well I have nothing better to offer
than just roll up your sleeves and get cracking on finding the bottle necks
and improving the code flow. I've mentioned my thoughts on this a few times
already and I believe most of them are now collected in the TODO.

Thanks a lot for the table though, it certainly is an eye-opener that we need
to get this fixed.

I wonder why I get so much higher performance when I do uploads over
localhost. I would expect a gigabit link with really fast roundtrips to get
similar speeds.

Received on 2010-10-22