very poor cygwin scp performance in some situations

[Steven Hartland]

----- Original Message ----- 
From: "Corinna Vinschen" 
> On Mar 27 16:39, Steven Hartland wrote:
>> I've done quite a bit of digging and not found any real answers
>> on why cygwin's scp performance is so poor.
> 
> Cygwin is just emulating POSIX by calling Windows functions.  It's not
> an operating system which runs natively on the machine, so what do
> you expect?  If you're unhappy with scp's performance you can try
> using:
> 
> - sftp
> 
> - tar over ssh:
> 
>    tar cf - dir-to-copy | ssh remotemachine 'cd targetdir && tar xf -'
> 
> - http://www.psc.edu/networking/projects/hpn-ssh/

Sorry to sound rude but did you even look at the figures I posted?

>From them I think its fair to say there is nothing to stop cygwin
performing quite well in all ssh / scp operations but as it stands there
are a number of issues; specifically copying off a cygwin machine
from a remote box which atm produces only 700KB/s.

The transfer the other way round obtains over 6MB/s which is pretty
good although could still possibly see some gains.

Always willing to trying things here's the results from your suggestions:
sftp provides a small improvement 1.1MB/s
tar + ssh is the same as scp 700KB/s
I'd already tried hpn but although it compiles fine just instantly
disconnects so is unfortunately a none starter.

I'm not sure what everyone uses cygwin for but I would be surprised
if a large amount of people dont use if for interaction with existing
unix systems and as such make heavy use of facilities such as ssh and
scp on a daily basis so any work on this would be highly beneficial.

I'm quite willing, as hopefully I've show, to put in some ground leg
work to try and find a solution to this one but due to my lack of
experience both with the core of cygwin and with ssh / scp without
some pointers Im not going to make much progress.

    Steve


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