Hi,
I must start by saying that I am a newbie on Ethereal
and on this type of analysis. I am seeking some
guidance from someone who might have already done this
type of work before.
...
I am trying to debug a problem related to X11
performance. We are running an application remotely on
both Solaris 8 and Linux 2.4.21. The application was
written in Qt and allows us to draw fairly complex
diagrams on the screen. We are observing some
performance issues when we drag blocks of a diagram on
the screen using the mouse. On Solaris, the blocks
move on the screen smoothly. They pretty much follow
the mouse closely. On Linux, the blocks move in big
jerks trying to catch up with the position of the
mouse. Sometimes they catch up fast and sometimes they
don't.
I am trying to use Ethereal to get an idea of what is
going on between the client and the server but I am a
bit clueless on how to proceed. Visually, I can tell
that the log of Solaris shows chunks of X11 packets
followed by chunks of TCP-ACK packets. The ACK packets
are always acknowledging some of the most recent X11
packets. It looks like everything is moving like
clockwork. On Linux though, I see a few X11 packets
followed by a couple TCP-ACK packets that sometimes
are acknowledging long-gone X11 packets. I suspect
that what I have found in the logs is the
manifestation of the problem that I see on the screen
although I really do not know much about the X11
protocol.
My questions to you are:
1. If you have already debugged this type of problems,
would you have any hints to me? Pointers to
documentation? Anything at all?
2. My inspection has been mainly visual so far. Am I
missing some features of Ethereal that could help me
dig on this issue a little further?
3. Can I use these logs to confirm whether I need to
tweak buffers or any other TCP parameters on the Linux
side? How can I go about reaching such a conclusion?
Any help is greatly appreciated.
Best Regards
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