<div dir="ltr">Where should I be running this from? I tried this from within my existing x2go session, but I get the following error:<div><br></div><div><div>_XSERVTransSocketINETCreateListener: ...SocketCreateListener() failed</div><div>_XSERVTransMakeAllCOTSServerListeners: server already running</div><div>Error: Aborting session with 'Cannot establish any listening sockets - Make sure an X server isn't already running'.</div></div><div><br></div><div>Then I tried it from within a VNC session. I was able to run the experiment you described, but I did not experience delays either with xcircuit or with my problematic app.</div><div><br></div><div>My server is entirely headless BTW. In fact, its a RHEL 6.6 virtual machine running on my company's VDI infrastructure.</div><div><br></div><div>Is there any value to giving you an xtrace dump with relative timestamps? When I do that, and then sort the log in order of increasing timestamp values (reported in seconds), I see BIG discontinuities where there can be DOZENS of seconds between consecutive timestamps.</div><div><br></div><div>I'm still betting that the problem has to do with the volume of X protocol messages. However, I'm not sure why this would be different in rootless vs. virtual desktop mode (I don't see the problem in virtual desktop mode).</div><div><br></div><div>Are you able to reproduce the delays that I'm seeing when running xcircuit directly within a rootless x2go session (i.e. NOT with your nxagent experiment). The whole point of using xciruit was because I wanted to find a FREE application that exhibits the problematic behavior, so that the developers could more easily reproduce the behavior.</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Nov 16, 2016 at 4:42 PM, Ulrich Sibiller <span dir="ltr"><<a href="mailto:ulrich.sibiller@gmail.com" target="_blank">ulrich.sibiller@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">On Thu, Oct 27, 2016 at 8:37 PM, Thomas Esposito <<a href="mailto:tmesposito00@gmail.com">tmesposito00@gmail.com</a>> wrote:<br>
> Package: x2goserver<br>
> Version: 4.0.1.19-3<br>
> Severity: critical<br>
><br>
> Server OS: RHEL6.6<br>
> Client OS: Windows 7 SP1 64-bit<br>
> Server Packages: x2goserver-4.0.1.19-3.el6.x86_<wbr>64<br>
> x2goagent-3.5.0.32-3.el6.x86_<wbr>64<br>
> nxagent-3.5.0.31-1.el6.x86_64 (not sure if this<br>
> is a dependency)<br>
> nx-libs-3.5.0.31-1.el6.x86_64 (not sure if this<br>
> is a dependency)<br>
> Client Version: 4.0.5.2<br>
><br>
> This only occurs when starting a terminal in seamless window mode, and then<br>
> launching the "problem" applications from that terminal. I imagine that I'd<br>
> observe the same behavior if launching the application directly when the<br>
> x2go session is created.<br>
><br>
> Certain applications experience catastrophically long delays (i.e.<br>
> unresponsive for several minutes) during startup and even more so during<br>
> reconnect (after a session is suspended). In particular, this happens with 2<br>
> Synopsys EDA (Electronic Design Automation) applications that I heavily rely<br>
> on, dve and verdi. Obviously, you won't be able to test these because they<br>
> require an expensive license, but I can tell you that they are older-style<br>
> X11 applications that user X server-side font rendering and probably don't<br>
> use a lot of other modern X client-side rendering techniques.<br>
><br>
> Luckily, I was able to find a free application that is similarly<br>
> unresponsive when starting up in seamless window mode, but that runs fine in<br>
> virtual desktop mode: xcircuit. This happens to be a free CAD program for<br>
> drawing circuit schematics. Obviously, I can't be 100% that this X11<br>
> application is failing in the same way as my proprietary EDA tools, but it<br>
> is something the x2go developers can look at regardless.<br>
><br>
> <a href="http://opencircuitdesign.com/xcircuit/" rel="noreferrer" target="_blank">http://opencircuitdesign.com/<wbr>xcircuit/</a><br>
><br>
> In order to diagnose the problem, I ran my applications under xtrace with<br>
> the '--relative-timestamps' option in order to see the kind of X11 protocol<br>
> traffic that was being generated. In both cases (i.e. my Synopsys EDA<br>
> applications and xcircuit), there appear to be MASSIVE amounts of<br>
> notifications and events going from the X server to the X client. It seems<br>
> like the application's window is made up of a TON on individual rectangle<br>
> primitives. If I filter the log file dumped out by xtrace to just show<br>
> timestamps, I see HUGE jumps/discontinuities where there are several seconds<br>
> or even minutes of apparent inactivity between consecutive messages.<br>
> According to top, x2goagent is NOT consuming an excessive amount of CPU<br>
> during these period of unresponsiveness.<br>
><br>
> I don't know much about the details of the X11 protocol, but it almost seems<br>
> as if there is some kind of message buffer overrunning somewhere causing<br>
> things to get out of sync, only recovering after some kind of watchdog or<br>
> timeout mechanism kicks in. If my theory is correct and this happens<br>
> repeatedly, it can add up to MINUTES of unresponsiveness. However, I'm not<br>
> sure why this would happen only in seamless window mode. Certainly, one<br>
> difference between seamless window mode and virtual desktop mode is that<br>
> when reconnecting after a suspend, seamless windows are probably going to<br>
> see a lot more events from the server (e.g. expose events, window<br>
> manipulation notifications, etc.) because of interactions with the locally<br>
> running windows which may be in a totally different state compared to when<br>
> the x2go session was suspended. In contrast, when running in a virtual<br>
> desktop, the applications are contained with a "box" that isolates it from<br>
> the state of the local windows on the x2go client side.<br>
><br>
> It is important to note that, for all of the applications that exhibit this<br>
> behavior, once the application has started up (or after suffering long<br>
> delays during an x2go reconnect), the application is perfectly functional<br>
> and responsive.<br>
<br>
This looks like a problem of nx. Can you please try this:<br>
1. run /usr/bin/nxagent -R -ac :5 (you'll see nothing)<br>
2. launch the problematic application:<br>
export DISPLAY=:5<br>
/usr/bin/problematic-app<br>
3. kill -HUP <pid of nxagent> (suspend session)<br>
4. wait some seconds<br>
5. kill -HUP <pid of nxagent> (resume session)<br>
<br>
Does this also show the delays? (it doesn't for me with xcircuit, but<br>
I seem to have<br>
some font trouble here. I get lots of 'Error: font encoding file<br>
missing for font "Helvetica"' messages).<br>
<br>
<br>
Uli<br>
</blockquote></div><br></div>