VNC getting slower and slower and slower

Dr. Joel M. Hoffman ()
Tue, 2 Jun 98 15:18 EDT

I'm running VNC over a slowish wireless Ethernet (4ms ping times),
both server and display running Linux. Usually everything works fine.
But sometimes the display gets stuck, and the only solution is to
abort xvncviewer and connect again. Then I see all my changes. Once
this starts, things get worse and worse. After waiting 2 full minutes
(!!) to see the words "slower and slower" on the screen, I gave up
and moved to another machine to finish typing this bug report. During
this time, I had a ping process running on another VC, and there were
almost no dropped packets and ping times were generally 4ms or 5ms,
with only occasional higher times.

My guess is that something is broken in the code that tries to
optimize the output to the link speed. Is this possible? Perhaps two
or three packets get lost, retransmitted, etc., and by the time things
are done round trip times for those few packets are in the 2 second
range, and so Xvnc stops sending data? Then when things settle down,
Xvnc refuses to start sending more data?

Anyway, I'l >really< like to find a solution to this. The details,
again, are these:

- Constant pinging between the two machines indicates ping times of
  4ms and almost no lost packets.

- Neither machine is loaded. (CPU is mostly idle.)

- VNC takes over two minutes to update three typed words!

Please help.

Thanks.

-Joel
()

This archive was generated by on Wed Feb 03 1999 - 15:34:37 GMT