Gnome slower than CDE over 100mbps network

[Coolmar]

Hi,

We are finding Gnome (installed on an HP Proliant DL380 G3 server with Redhat Linux ES rel. 4) extremely slow over the network. Obviously, that would generally point to bandwidth...however, accessing CDE on an HPUX 11i system is quick. Both are being accessed through Exceed. Any ideas on why one would be slow and not both or neither?

Thanks!

[Steven E. Protter · Accepted solution]

Several things to think about here.

The HP-UX box, how many processors does it have and how modern are it. HP-9000 servers are optimized and all other factors being equal, that could explain the problem, not bandwidth. Also, PA-RISC is a totally different architecture.

Another factor is the network and kernel on your comparision are totally different. HP-UX is optimized in a different way, and has been around a lot longer than Linux.

CDE is a much simpler, less feature rich environment. CDE tries to do a lot of the things that Windows does, and it has more code.

In short, the comparison may not be valid.

That being the case, you should run the mii-tool command and check that you are getting proper settings on the Linux box.

ethtool is also useful.

ethtool eth0

You should make sure you are maximizing your switch settings, probably it should be auto negotiate, 100 BaseT full duplex.

Next thing to look into is the switch port settings on the port the Linux box is connected to. It should be auto negotiate for most nic cards. Manual settings will have a significant, negative impact on the network throughput.

SEP

[Gopi Sekar]

you are trying to compare two different machines having two different window manager.

Gnome is more feature rich containing lot of server side code. screen refreshing rate (thus packet transferring) could be much much more compared to CDE(which seems to be elegant and simple)

there are few things you can try to increase the network throughput.

* Change the default theme and style of GNOME. RH puts heavy themes and color schemes which you may not require. use some simple and not so heavy.

* by default, the up2date client runs on GUI (flashing Red icon on the taskbar), disable it

* use gnome control panel to modify effects setting. gnome allows to modify effects for various GUI windows (like pull down menu's etc)

* if exceed can support packet compression then use it.

Regards,
Gopi

[Coolmar]

Thanks for the info, it really helps. I had previously set ethtool for

speed 100 duplex full and autoneg off

The switch is set to the same thing. It seems when we have autoneg set to ON, the box gets really really slow. So I think you may be right as far as Gnome being heavy graphics and just alot more "junk" in it than CDE has.

Thanks again!

[Steven E. Protter]

Working over the network configuration for the best combination will help, but you are right Gnome has a lot more junk.

SEP

[Coolmar]

Ok. Found more information out:

The person who is finding it slow is in another city. I am located on the same network as the servers (hp and linux) and the Gnome comes up as quickly as my CDE. However, the user in the other city accesses CDE very quickly, but Gnome takes a long long time.

What about the XDMCP settings in gdmsetup? There are alot of settings under Honor Indirect Requests...could any of them make a difference? I am at a loss here. If it were a network issue, she would notice at least *some* latency with CDE, but it is very quick.

Thanks!

[Gopi Sekar]

looks like gnome is transferring too much of packets over the network. there are two ways to this problem: either use different light weight window manager (fvwm2) or compress the packets between server and client. see whether it is possible to do hardware compression at the modem layer otherwise you have to go to software compression.

Try using VNC (http://www.realvnc.com) instead of exceed, i believe it has built in compression support which is good for transferring packets over modem lines

or you can take a look at NX (http://www.nomachine.com/) or the freeware implementation of it http://download.berlios.de/freenx/


Regards,
Gopi

[Coolmar]

The user in the other city is not using modem lines...we have a 1gb between here and her city. So it should be quick.

[Mike Stroyan]

A high bandwidth connection may have poor X11 performance because of high latency. Some application behaviors can require many round trip replies from the X server. That could be making gnome seem much slower than CDE.

One possible cure is to us the LBX "low bandwidth X" extension. Its name implies it is all about bandwidth, but it also does some round trip elimination by caching values in the lbxproxy command on the same system as the gnome X clients. There is a note on using LBX with exceed at http://www.hummingbird.com/support/nc/exceed/ex6_lbx.html.

You could also try using Xvnc on the linux system and vncviewer on the remote system. That actually puts an X server on the same host as the clients to eliminate round trip delays. It might use quite a bit more bandwidth to push the vnc protocol across the network. See "man Xvnc".

[Coolmar]

Mike,

The link you posted is not working for me. What little I could find on lbx looks like it is for when using a modem....we have a T1 line.

Sally