#49 port doesn't close for bad mcast connection

open
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5
2008-09-09
2008-09-09
Paul Fitzpatrick
No

Lorenzo is seeing some problems closing a port when an incoming mcast connection is flakey. He found that the problem can be made more replicable by reducing the system buffer size:

>If I run the same test on my laptop (Linux Ubuntu) things work ok. However I manage to replicate the problem with the framerate (the fact that it does not shutdown correctly), if I reduce the receiver buffer.

> with:

> sudo /sbin/sysctl net.core.rmem_max=51200

> or

> sudo /sbin/sysctl net.core.rmem_max=40960

> I see more and more packets being lost, but the program still quits ok.

> when I go down to 30720 I start see the problem I described above.

Discussion

  • Full test-case for Linux, where "framerate" is from example/framerate in YARP CVS on or after today's date:
    sudo /sbin/sysctl net.core.rmem_max=4000
    yarp server
    yarpdev --device test_grabber # gives 320x240 images on port /grabber
    ./framerate --local /local --remote /grabber --prot mcast
    killall framerate
    (use new terminals as necessary).

    With "--prot mcast", port fails to close on kill.
    With "--prot tcp", port closes just fine.
    -Paul