X-forwarding very very slow

X-forwarding very very slow

[Alberto Canestrelli]

Hi,
I have a problem with Cygwin. I am connecting from USA by ssh to the 
Hector supermachine in Edinburgh ( I write "startx" in Cygwin and then I 
use  "ssh -Y  v1acanes@login.hector.ac.uk" ). Everything works fine, the 
only problem is that the forwarding of the windows is very very slow. It 
takes sometimes also up to 5 minutes to open a new window. I am 
debugging a code with Totalview and it is a impossible to work. I am in 
contact with the Hector support and with their computer they tried to 
run Cygwin under windows and connecting by ssh (exactly like I am doing) 
and they say that x-forwarding  is fast. My version is:

CYGWIN_NT-5.1 1.7.1(0.218/5/3) 2009-12-07 11:48

while their version is:

CYGWIN_NT-6.0 1.5.25(0.156/4/2) 2008-06-12 19:34

So my version is more recent. I do not fell like to downgrade Cygwin,  
everything works well save the slow X-forwarding. Any suggestion please?

Thank you very much
best regards
Alberto

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Re: X-forwarding very very slow

[Daniel Colascione]

On 8/18/10 8:43 AM, Alberto Canestrelli wrote:
> I have a problem with Cygwin. I am connecting from USA by ssh to the
> Hector supermachine in Edinburgh ( I write "startx" in Cygwin and then I
> use  "ssh -Y  v1acanes@login.hector.ac.uk" ). Everything works fine, the
> only problem is that the forwarding of the windows is very very slow. It
> takes sometimes also up to 5 minutes to open a new window. I am
> debugging a code with Totalview and it is a impossible to work. I am in
> contact with the Hector support and with their computer they tried to
> run Cygwin under windows and connecting by ssh (exactly like I am doing)
> and they say that x-forwarding  is fast.

The performance they're seeing probably has little to do with their
Cygwin version --- they're a lot closer, after all, so support's latency
is probably a lot lower.

NX actually works under Cygwin, though it's a pain to compile (and
unsupported I imagine). This document provides an introduction to
getting the system to work:

http://www.nomachine.com/documentation/building-components.php


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Re: X-forwarding very very slow

[Larry Hall (Cygwin)]

On 8/18/2010 11:50 AM, Daniel Colascione wrote:
> On 8/18/10 8:43 AM, Alberto Canestrelli wrote:
>> I have a problem with Cygwin. I am connecting from USA by ssh to the
>> Hector supermachine in Edinburgh ( I write "startx" in Cygwin and then I
>> use  "ssh -Y  v1acanes@login.hector.ac.uk" ). Everything works fine, the
>> only problem is that the forwarding of the windows is very very slow. It
>> takes sometimes also up to 5 minutes to open a new window. I am
>> debugging a code with Totalview and it is a impossible to work. I am in
>> contact with the Hector support and with their computer they tried to
>> run Cygwin under windows and connecting by ssh (exactly like I am doing)
>> and they say that x-forwarding  is fast.
>
> The performance they're seeing probably has little to do with their
> Cygwin version --- they're a lot closer, after all, so support's latency
> is probably a lot lower.

Agreed.  I would point out, however, that the OPs Cygwin versions are
pretty out-of-date as well.  Though I'm not sure it will help in this
particular matter, it's worth thinking about upgrading.

-- 
Larry Hall                              http://www.rfk.com
RFK Partners, Inc.                      (508) 893-9779 - RFK Office
216 Dalton Rd.                          (508) 893-9889 - FAX
Holliston, MA 01746

_____________________________________________________________________

A: Yes.
> Q: Are you sure?
>> A: Because it reverses the logical flow of conversation.
>>> Q: Why is top posting annoying in email?

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Re: X-forwarding very very slow

[Csaba Raduly]

On Wed, Aug 18, 2010 at 5:43 PM, Alberto Canestrelli wrote:
> Hi,
> I have a problem with Cygwin. I am connecting from USA by ssh to the Hector
> supermachine in Edinburgh ( I write "startx" in Cygwin and then I use  "ssh
> -Y  v1acanes@login.hector.ac.uk" ). Everything works fine, the only problem
> is that the forwarding of the windows is very very slow.

Hi Alberto,
It would be useful if you could try a non-Cygwin X server (e.g. a
Linux or Solaris workstation). If X from under Linux appears fast,
then the slowdown could be between your network card and display
(probably Cygwin's fault). If X from Linux is also slow, the problem
may be with the propagation of the X protocol between your network
card and Hector (probably not Cygwin's fault) .

-- 
Life is complex, with real and imaginary parts.
"Ok, it boots. Which means it must be bug-free and perfect. " -- Linus Torvalds
"People disagree with me. I just ignore them." -- Linus Torvalds

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Re: X-forwarding very very slow

[Jeremy Bopp]

On 8/18/2010 11:55 AM, Csaba Raduly wrote:
> On Wed, Aug 18, 2010 at 5:43 PM, Alberto Canestrelli wrote:
>> Hi,
>> I have a problem with Cygwin. I am connecting from USA by ssh to the Hector
>> supermachine in Edinburgh ( I write "startx" in Cygwin and then I use  "ssh
>> -Y  v1acanes@login.hector.ac.uk" ). Everything works fine, the only problem
>> is that the forwarding of the windows is very very slow.
> 
> Hi Alberto,
> It would be useful if you could try a non-Cygwin X server (e.g. a
> Linux or Solaris workstation). If X from under Linux appears fast,
> then the slowdown could be between your network card and display
> (probably Cygwin's fault). If X from Linux is also slow, the problem
> may be with the propagation of the X protocol between your network
> card and Hector (probably not Cygwin's fault) .

You could also try enabling compression with -C.  I have found this to
be a necessity when connecting with X over ssh between work and home
even though the locations are quite near each other and plain text based
ssh access runs fine without the compression.

-Jeremy

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Re: Re: X-forwarding very very slow

[Ryan Johnson]

  On 8:59 PM, Jeremy Bopp wrote:
> On 8/18/2010 11:55 AM, Csaba Raduly wrote:
>> On Wed, Aug 18, 2010 at 5:43 PM, Alberto Canestrelli wrote:
>>> Hi,
>>> I have a problem with Cygwin. I am connecting from USA by ssh to the Hector
>>> supermachine in Edinburgh ( I write "startx" in Cygwin and then I use  "ssh
>>> -Y  v1acanes@login.hector.ac.uk" ). Everything works fine, the only problem
>>> is that the forwarding of the windows is very very slow.
>> Hi Alberto,
>> It would be useful if you could try a non-Cygwin X server (e.g. a
>> Linux or Solaris workstation). If X from under Linux appears fast,
>> then the slowdown could be between your network card and display
>> (probably Cygwin's fault). If X from Linux is also slow, the problem
>> may be with the propagation of the X protocol between your network
>> card and Hector (probably not Cygwin's fault) .
> You could also try enabling compression with -C.  I have found this to
> be a necessity when connecting with X over ssh between work and home
> even though the locations are quite near each other and plain text based
> ssh access runs fine without the compression.
In my experience, any "off-campus" access to X is best done via VNC or 
rdesktop (both over a compressed ssh tunnel). Triply so if you're 
crossing an ocean. The protocol simply was not designed with slow or 
laggy networks in mind, from what I can tell.

There are faster X-servers for windows, but not free, and I haven't 
noticed that they reduce the amount of protocol chatter much, especially 
for the unbearably slow process of opening a new window.

Regards,
Ryan


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