Wireshark-users: Re: [Wireshark-users] Nondeterministic 200 ms delay between sends (5Frames per S
Hi,
I would check two things (may be you already did it):
1- Check whether both TCP channels keep connected during the whole process, or they´re reconnecting all the time.
2- Check whether the synch messages are doing well since it looks like a synchronization problem.
BR,
Juan
>-----Original Message-----
>From: wireshark-users-bounces@xxxxxxxxxxxxx
>[mailto:wireshark-users-bounces@xxxxxxxxxxxxx] On Behalf Of
>ext Kovacs Peter Tamas
>Sent: Viernes, 07 de Marzo de 2008 10:51 a.m.
>To: wireshark-users@xxxxxxxxxxxxx
>Subject: [Wireshark-users] Nondeterministic 200 ms delay
>between sends (5Frames per Sec)
>
>Dear All,
>
>maybe this is a bit offtopic here, but I don't know a better
>place to find experts who might have the answer for my question.
>What we do is an application consisting of two parts, one that
>captures an application's OpenGL call stream, and an other one
>that receives and re-renders it on another machine.
>In out current configuration, the capture side runs on a
>Windows XP x64 machine, connected to 16 Linux receivers with a
>Gigabit Ethernet network. All communication goes through TCP
>channels (two per client, one for data, another for sync).
>
>Now this application runs real-time most of the times
>(achieving >100 Frames per Second in some cases). But
>sometimes, when capturing an application's OpenGL stream,
>frame rate is limited to 5 FPS, and stays there forever. If I
>stop it, and restart the app (don't change anything), it
>usually runs fast. Sometimes it is slow 5 times in a row.
>Sometimes it runs correctly for 20 times in a row.
>If it's fast when the application started, it remains fast for
>the whole run. If it starts slow then it remains slow for the
>whole run.
>When it's slow and when it's fast seems to be totally
>undeterministic for me.
>
>I thought it might be a network problem, so I've run Wireshark
>on the capture machine, and looked at the trace. All I've seen
>is that packets are sent in 200 ms intervals. Some packets are
>sent our rapidly, then nothing happens for 200 ms, then
>another bunch of packets are sent. No errors, no warnings in
>the expert info, nothing strange. It's simply the host that
>waits ~200 ms for some unknown reason.
>We've already tried TCP_NODELAY, now all our sockets are
>created with this, but it does not help. We tried changing the
>network adapters, increasing buffer sizes, nothing helped so far.
>
>BTW, this never happens if the capture machine is a Linux box too.
>
>Does anybody have an idea about why this could happen? I'm
>open for every weird idea, as this is very annoying.
>
>
>Thanks for your kind help in advance,
>Peter Kovacs
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