High network usage with remote X session

trojanfoe · 08-05-2009, 06:36 AM

Hi there, I am trying to figure out why the remote X performance of our RedHat 5.3 system is so bad. We have tried using X (Gnome session) from several different X Servers (Windows Xceed, Windows XWinPro, Linux Xnest - both Fedora 11 and Centos 5.3 and Mac OS Xnest) and the system is barely usable. I have monitored the network traffic on the RHEL system and it goes up to 6MB/s at some points, which seems a bit too high for X net traffic? I have disabled ipv6 and any ip_tables modules and that has helped a bit, but it's still not very good.

I suspected the network hardware and driver, but I cannot see how that would cause network traffic problems. The network hardware is Marvell 88E8056 with the sky2 driver (1.14), both of which seem much-maligned:

Code:

[root@orion ~]# lspci | fgrep Marvell
04:00.0 Ethernet controller: Marvell Technology Group Ltd. 88E8056 PCI-E Gigabit Ethernet Controller (rev 12)
06:00.0 Ethernet controller: Marvell Technology Group Ltd. 88E8056 PCI-E Gigabit Ethernet Controller (rev 12)

[root@orion ~]# modinfo sky2
filename:       /lib/modules/2.6.18-128.2.1.el5/kernel/drivers/net/sky2.ko
version:        1.14
license:        GPL
author:         Stephen Hemminger <shemminger@linux-foundation.org>
description:    Marvell Yukon 2 Gigabit Ethernet driver
srcversion:     24BB88B15DBF35BF3881E0F
alias:          pci:v000011ABd0000436Bsv*sd*bc*sc*i*
alias:          pci:v000011ABd0000436Asv*sd*bc*sc*i*
alias:          pci:v000011ABd00004369sv*sd*bc*sc*i*
alias:          pci:v000011ABd00004368sv*sd*bc*sc*i*
alias:          pci:v000011ABd00004367sv*sd*bc*sc*i*
alias:          pci:v000011ABd00004366sv*sd*bc*sc*i*
alias:          pci:v000011ABd00004364sv*sd*bc*sc*i*
alias:          pci:v000011ABd00004363sv*sd*bc*sc*i*
alias:          pci:v000011ABd00004362sv*sd*bc*sc*i*
alias:          pci:v000011ABd00004361sv*sd*bc*sc*i*
alias:          pci:v000011ABd00004360sv*sd*bc*sc*i*
alias:          pci:v000011ABd00004356sv*sd*bc*sc*i*
alias:          pci:v000011ABd00004353sv*sd*bc*sc*i*
alias:          pci:v000011ABd00004352sv*sd*bc*sc*i*
alias:          pci:v000011ABd00004351sv*sd*bc*sc*i*
alias:          pci:v000011ABd00004350sv*sd*bc*sc*i*
alias:          pci:v000011ABd00004347sv*sd*bc*sc*i*
alias:          pci:v000011ABd00004346sv*sd*bc*sc*i*
alias:          pci:v000011ABd00004345sv*sd*bc*sc*i*
alias:          pci:v000011ABd00004344sv*sd*bc*sc*i*
alias:          pci:v000011ABd00004343sv*sd*bc*sc*i*
alias:          pci:v000011ABd00004342sv*sd*bc*sc*i*
alias:          pci:v000011ABd00004341sv*sd*bc*sc*i*
alias:          pci:v000011ABd00004340sv*sd*bc*sc*i*
alias:          pci:v00001186d00004B03sv*sd*bc*sc*i*
alias:          pci:v00001186d00004B02sv*sd*bc*sc*i*
alias:          pci:v00001186d00004001sv*sd*bc*sc*i*
alias:          pci:v00001186d00004B00sv*sd*bc*sc*i*
alias:          pci:v00001148d00009E00sv*sd*bc*sc*i*
alias:          pci:v00001148d00009000sv*sd*bc*sc*i*
depends:        
vermagic:       2.6.18-128.2.1.el5 SMP mod_unload gcc-4.1
parm:           debug:Debug level (0=none,...,16=all) (int)
parm:           copybreak:Receive copy threshold (int)
parm:           disable_msi:Disable Message Signaled Interrupt (MSI) (int)
module_sig:     883f3504a54c45cae5b2b8a3522b187112b6400a08b3043a142c994291d1cd8ca6cd71175306274a60a08529b8b19b36f2f24d9d8bb3d433a63a36378b56

I wonder if there are any X Server network settings I might check, or whether trying XFCE would be a better option over Gnome. If so, do I have get the xfce group from a CentOS Repo, or is there something better suited to RHEL?

Any help would be much appreciated,
Regards,
Andy

trojanfoe · 08-05-2009, 09:54 AM

As an update, I have tried the 'disable_msi=1' sky2 option, but that doesn't make any difference. One observation that puzzles me is the RHEL server, running the Gnome session, receives more data than it transmits. Surely most of the data involved is graphics data being transmitted from this server? Does this ring any bells with anyone?

I have also tried explicitly setting '-bs' and then '+bs' on the Xnest command line and that makes no difference either - I think it ought to have made some difference.

Cheers,
Andy