X-Spam-Check-By: sourceware.org
X-Sender: @ (Unverified)
Date: Sat, 18 Mar 2006 22:03:42 +0100
To: "Max Stein" <Grizzly99 AT gmx DOT de>, <cygwin AT cygwin DOT com>
From: Arend-Jan Westhoff <jpmcyafvmhsl AT spammotel DOT com>
Subject: Re: sshd and scp/sftp: slow throughput on windows machines
In-Reply-To: <003501c64a2e$3dede630$f4598350@HAUPTPC>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Message-Id: <20060318210347.8FB7A2680@dot.warande.net>
Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm
Precedence: bulk
List-Unsubscribe: <mailto:cygwin-unsubscribe-archive-cygwin=delorie DOT com AT cygwin DOT com>
List-Subscribe: <mailto:cygwin-subscribe AT cygwin DOT com>
List-Archive: <http://sourceware.org/ml/cygwin/>
List-Post: <mailto:cygwin AT cygwin DOT com>
List-Help: <mailto:cygwin-help AT cygwin DOT com>, <http://sourceware.org/ml/#faqs>
Sender: cygwin-owner AT cygwin DOT com
Mail-Followup-To: cygwin AT cygwin DOT com
Delivered-To: mailing list cygwin AT cygwin DOT com

At 02:49 2006-03-18 +0100, Max Stein wrote:
>Unfortunately, the performance of the cygwin sshd server is very poor when 
>it comes to copying large files. I have made this observation on several new 
>and fast machines (3 GHz, 512 MB RAM, 100 MB/s Intel Pro network card) 
>running with Windows XP or Windows 2003 Server. The best speed achievable 
>was about 4 MB/s when copying a file from the SSH client to the SSH server; 
>when doing it the other way round, the throughput was even worse, about 2.3 
>MB/s. I tried it on three different machines running the newest version of 
>cygwin's sshd und scp/sftp. The results were approximately the same.
>Neither the client's nor the server's processor was really busy. The CPU 
>usage oscillated around 30-40%.
>
>Setting up the same scenario on linux yielded a completely different 
>picture. Using the Knoppix disc 4.0.2 on the client and the server machine I 
>easily achieved a throughput of 10.8 MB/ in both directions (pushing a file 
>to the server or downloading a file from it).
>
>What could be done to improve the performance of cygwin's SSH server? There 
>were already some older posts dealing with the same problem but nobody had 
>really a constructive idea or proposal.
>

1. Is it possible to increase the bandwith by having the client aggregate 
multiple sessions through a single pipe?
2. It would seem that PPTP connections can be much faster. E.g. a FreeBSD 
MPD running on a 400 Mhz Pentium II can sustain a 50 Mbit/s datastream at a
CPU usage of 25%.
W2k and XP have easy to configure PPTP clients.
(See also W2003 RAS.)

HTH,

Arend-Jan Westhoff.

--
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple
Problem reports:       http://cygwin.com/problems.html
Documentation:         http://cygwin.com/docs.html
FAQ:                   http://cygwin.com/faq/