are there ways to speed X operation up?
 

Hi

I have X server software on my PC (win2000) and connecting to my Linux machine using wireless lan (802.11g), there's nothing much else happening on the LAN (only me in here) yet it seems dreadfully slow on refresh rates even in text only terminals. Is there some way of 'tuning' this or is it just slow by nature (in contrast my SSH text only connections are quite responsive)?

ping results (both ways)

I'm not sure I understand your question but it comes off as if you are doing X11 forwarding to launch applications on your Linux machine to your Windows machine? Is that right?

... well I'm under the impression that the thing which runs the display is called the 'server' and in this case its a windows box. I then connect to the Linux machine (where the applications actually run).

so I think thats a yes to your question.

anyway, refresh is very sluggish on the location where the keyboard / mouse / screen are (which is over the LAN).

Which X server are you using?

I'm using xwin release 6.8.99.901-4 from the Cygwin/X Project.

It is painfully slow (over a 100Mbit wired LAN). I don't know whether the problem is xwin or Windows or the Linux systems I'm accessing.

So if you learn anything, I'm also interested.

Obviously, an SSH text connection is far less work for every part of the system, so it should be more responsive.

You have to understand that (no matter how you do it) running a remote GUI uses a LOT of bandwidth. Wireless rapidly losses bandwidth with distance. You can help yourself out by dropping the amount of information being transmitted as much as possible. Drop down to 16 colors and drop the resolution as low as possible.

you could use an ethernet connection to temporarily bypass the wireless function
You could boot the PC into safe mode to bypass the items in the Startup Group
You could borrow another PC to swap out the existing pc for test purposes

If bypassing the wireless function resolves the issue encrypt using WPA and look for sources of interference such as Cordless phone bases operatiing on 2.4G.

If it runs in Safe mode. Run Virus and Spyware scans and do a Binary Search on the Items in the Startup Group.

If you can replace the PC and you find joy. Then you are pretty close to reloading the OS or adding more memory to one or both machines.

<digs into recesses of brain> Isn't there a -c (or maybe -C) switch that compresses the data stream? </end dig>. Or am I getting confused with tunnelling the data stream over ssh?

Have you the opportunity of testing a pure wired system to see how the speed of that compares? Data rates on wireless are very variable (depending on distance, obstructions, alignment of the antennas, interference/noise) and wired would give you much closer to a 'standard' situation.

ping can also be used to test with significant amounts of data (rather than the default of just testing turn around time).
I just tried:
So I'm getting 5.5 MByte per second through my 100Mbit connection. With ZERO overhead 100Mbit would be 12.5 MByte. So 5.5 is worse than you'd expect, but not really rotten.

I don't know an easy way to measure how much data xwin needs, so I suspect mine is slow for reasons other than the 5.5MB per second performance of the connection. But I don't know how to better investigate that.

You may be dealing with very different performance issues than I am, so that ping test with a significant data size may give you more relevant information.

The theoretical is 12.5 but the average person will see more like 9.5 (at best).

Hi

interestingly my ping seems not to have that option (in that way) as ping here seems to be:

stop press: I just found this option on my windows box side of the equation!

John


I initially wanted to use 10/100 but my internal motherboard card wasn't recognised, after getting another which didn't get recognized I eventually settled on this wireless card (which seems to be getting reasonable connections based on iwconfig output)

I don't believe that there are any hassles with the Win PC as it is quite the "little ripper" actually, and bustles along nicely, the latency issues are certainly network related as the other PC here (a P-III 600 with win2K) seems to display identically to the other. CPU barely hits 50% during X11 operations (even full screened).

I think I'll just have to live with it ...

thanks to everyone for their valuable input

Have you tried using VNC instead of X forwarding? I found that the difference between X forwarding over the internet compared with VNC over the internet to be significant improvement; that is to say, I can comfortably use VNC over the internet, but could not comfortably use apps with X forwarding. VNC (Tightvnc) is freely available for both Linux and Windows (server and client), so there's no interoperability issues, and over a LAN, speeds should be more than adequate.

I have only the ssh port open on my router, so have to forward ports using ssh before I can see my vncserver, but it isn't too much hassle. The best howto I've found on this is here: http://www.ibm.com/developerworks/li...AGX59&S_CMP=GR (scroll down to trick 6). You can compress the data using jpeg compression, which degrades the image slightly, but is otherwise perfectly useable. You can also switch compression off, though things start to lag for me if I do (remember, I'm doing this over the internet, not LAN).

If you're firewall free, or if you poke holes in the Windows firewall (you should get a pop-up asking if you want to) and also in the Linux one (if you have one running), it should be as simple as, from the Linux box:and then from the Windows boxI'm assuming you're using something like puTTY in Windows?...

edit: stupid me! Windows has a GUI client to connect with, so you'd open that, and enter either the IP followed by :99 (192.168.1.65:99), or if it works, the linuxserver's hostname followed by :99 (linuxserver:99).

To date, this is the most satisfactory solution I've found to accessing my computer at home from work graphically (as opposed to plain old terminal ssh).