Gazebo, gzclient, pins the CPU. We don't see this when using ssh -X, e.g., from a Mac with XQuartz, nor Windows with MobaXterm.

5.7.15-200.fc32.x86_64, gazebo-11.1.0-2.fc32.x86_64


top - 09:31:06 up 33 days, 17:28,  4 users,  load average: 2.15, 0.74, 0.44
Tasks: 806 total,   3 running, 803 sleeping,   0 stopped,   0 zombie
%Cpu(s): 17.6 us,  0.4 sy,  0.0 ni, 81.7 id,  0.0 wa,  0.1 hi,  0.1 si,  0.0 st
MiB Mem : 128537.7 total,  58096.7 free,  11477.8 used,  58963.1 buff/cache
MiB Swap:  15260.0 total,  15178.2 free,     81.8 used. 115554.7 avail Mem

    PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND
 523200 me 20   0   14.0g 343892 146472 R 826.2   0.3   2:40.46 gzclient
 523199 me 20   0   12.0g 200884 117124 S   7.6   0.2   0:03.21 gzserver
 521547 me 20   0  202364  94772  25548 S   4.3   0.1   0:03.45 x2goagent

We see this in /var/log/messages:

Sep 22 09:30:11 us dbus-broker-launch[522115]: Activation request for 'org.a11y.atspi.Registry' failed.

And from launching with verbose option:

[Wrn] [GuiIface.cc:119] X server does not support XInput 2
[Wrn] [GuiIface.cc:119] QXcbConnection: XCB error: 1 (BadRequest), sequence: 168, resource id: 158, major code: 130 (Unknown), minor code: 47

Is this a Gazebo issue?