[X2Go-Dev] NX3.5 speed degradation

[Eugene San]

Hi all,

I want to discuss the subject.

Story goes like this:
About 6 months, while planning upgrade (Ununtu 11.04->11.10) I've
noticed severe degradation in speed of NX sessions.
At the time I've decided to wait until LTS release, while being sure
issue is related to GUI changes in Ubuntu.
Recently I've reviewed the situation with 12.04 and found that problem
is still there and related to NX and not to GUI changes in Ubuntu.
My guess is that surrounding changes in distribution cause NX agent to
misbehave.

Overall user experience became unusable even on LAN and localhost connections.

Now to the details:
1. Screen redraw operations lags heavily even on local links.
    Instant (sub 0.5sec) on U10.04, up to 5 seconds on U12.04.
2. Constant screen redraws consume much more traffic.
    Sub 100kbps on U10.04.
    10mbps+ on U12.04 (Creating session with WAN quality settings and
reconnecting with LAN, lowers bandwidth to sub 1mbps but picture
quality suffers)
3. NX4 on U12.04 is faster 3x (in average) than 3.5 on U10.04.
4. NX3.5 on U12.04 is slower 3x then NX3.5 on U10.04 (some tests are
x1000 slower!)
5. Hybrid NX3.5<->NX4 is slow with NX3.5 as server and fast with NX4 as server.

Some details:
  * I've evaluated both 32 and 64 bit platforms.
  * I've compared fresh Ubuntu 10.04 and 12.04.
  * Both Nomachine NX binaries and X2GO binaries (ppa:x2go/ppa) were tested.
  * For reference I've performed NX4 and hybrid NX3.5<->NX4 testing.
  * Tested several usecases:
    * Desktop with manual operation of terminal, webbrowser and random
GUI application.
    * Rootless UnixBench in graphics mode. (Note in 64bit test caches NX agent!)
    * Desktop UnixBench in graphics mode. (Note in 64bit test caches NX agent!)
    * Rootless Xterm with scrolling text (ls -R /)

Please provide your feedbacks.