Slow performance over VPN/cable modem

[Alexander Gottwald]

On Fri, 21 Nov 2003, Bruce A. Hamilton wrote:

> XP Pro SP1, Pentium 2.66 GHz, 1 GB memory.
> 
> I am running the latest cygwin including XFree86 4.3.0.
> 
> Performance connecting to my workplace via VPN over cable modem is 
> painfully slow, similar to what I used to see running X over dialup years 
> ago. I'm running a local window manager fvwm2 then "ssh -X" to hosts at 
> work via my local xterms.

Afair cable modems have a high latency. 

> The app I'm most interested in is Veritas NetBackup 4.5 jnbSA, which is 
> written in Java and not exactly speedy even at work, but at work we are 
> talking a couple of seconds to refresh the screen, versus nearly a minute 
> for the tiniest changes at home.

Does this application use Swing? If so then the slow performance is not a 
problem of X11 but a design error of Java/Swing. All graphicsoperations in 
Swing are localy drawn into a bitmap and the bitmap is then transferred to 
the xserver. This is much more expensive than letting the xserver perform
the drawing operations.

> Thanks for any suggestions. I'm quite sure this in an X issue. Wasn't MIT 
> supposed to be working on "low-bandwidth X" years ago?

They never thought of Java.

bye
	ago
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 Alexander.Gottwald@s1999.tu-chemnitz.de 
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