Why does X-forwarding firefox take so long?
By Sophia Hammond
I ssh -X from Ubuntu to an Ubuntu Server, on which I've installed X, x11-apps and Firefox. Running xeyes shows the eyes, so I know that the X forwarding works. But when I try firefox, nothing happens: no window pops up, and the terminal line isn't returned until I ctrl+C.
How to debug this? I don't have physical access to the server.
ps aux shows:
me 22016 1.0 0.8 53464 9076 pts/1 S+ 17:20 0:00 /usr/lib/firefox-10.0.2/firefox
me 22018 0.0 0.0 0 0 pts/1 Z+ 17:20 0:00 [firefox] <defunct>Update: After waiting for 8 min, a Firefox window popped up and worked fine, without lag or any other problems. So the new question is: why does it take so much time?
42 Answers
If you are tunnelling your X11 through ssh, you might want to add compression to the tunnel as well. This can increase performance if bandwidth is scarce.
for example something like this
ssh -CX -c blowfish yourname@yourhostYou may want to check the amount of data transmitted through the network and the bitrate. I like to use 'dstat 60' for that. ($ sudo apt-get install dstat). Check if you see a lot of network traffic on either side, server and client) and if the rate is anywhere near the network bandwidth available. Notice that WAN links, DSL lines, Internet may have lower bandwidth than your network interface.
Check the top command for a hight iowait percentage. Press 1 to view per core statistics. High numbers of iowait usually indicate your CPU is waiting for data from the disks.
