Random high load with rtp streaming

[jhr]

I've noticed, that my simple stream without transcoding sometimes works as expected and sometimes gets caught in some kind of busy loop eating all the CPU cycles available. The command line is:

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vlc http://192.168.255.33:8081 --sout "#rtp{dst=239.193.0.1,port=8000,mux=ts,ttl=1}" -vvvvv

Normal expected behaviour gives following performance (top):

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PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 1473 root 20 0 44548 19740 12600 S 6.9 1.9 0:01.19 vlc

However every now and then I get this kind of figures:

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PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 1500 root 20 0 50704 25272 12812 S 149.9 2.5 0:21.31 vlc

Any ideas where to start? No error messages, however after the high load situation ctrl-d won't terminate the program. It'll kill the stream but load is still high. I'll have to keep hitting ctrl-c for a while. The frequency is 4 times out of 5 starts I get the high load. VLC version is 2.2.1 (Debian 8 ) and I don't have exact version where it was broken. I tested 1.0.5 in my old server and it didn't have any issues.

Quick update, it's 4th thread created that hangs (in case this helps):

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UID PID PPID LWP C root 2740 1 2740 0 root 2740 1 2741 0 root 2740 1 2760 0 root 2740 1 2763 99 root 2740 1 2765 0

The test source stream is just simple H.264 720p streamed from VLC (will eventually be IPTV source) with command:

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vlc Mark\ Ronson\ -\ Uptown\ Funk\ ft.\ Bruno\ Mars720p.mp4 --sout '#standard{access=http,mux=ts}' --http-host 192.168.255.33 --http-port 8081

[Rémi Denis-Courmont]

Break in a debugger and see which thread is busy looping.

[jhr]

It's the playlist module, it constantly calls parse_tracklist_node() in modules/demux/playlist/xspf.c. No idea why, just 5 minutes ago I learned what xspf is. Here's the backtrace, hope this helps:

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(gdb) bt #0 0xb759b508 in _IO_vfprintf_internal (s=s@entry=0xb58f0da0, format=<optimized out>, format@entry=0xb71c897f "%s <vlc:item tid=\"%i\" />\n", ap=0xb58f0e90 "\213,", ap@entry=0xb58f0e8c "\270\037㳋,") at vfprintf.c:1642 #1 0xb76525a1 in __GI___vasprintf_chk (result_ptr=result_ptr@entry=0xb5e1a020, flags=flags@entry=1, format=format@entry=0xb71c897f "%s <vlc:item tid=\"%i\" />\n", args=args@entry=0xb58f0e8c "\270\037㳋,") at vasprintf_chk.c:66 #2 0xb76524c7 in __asprintf_chk (result_ptr=0xb5e1a020, flags=1, format=0xb71c897f "%s <vlc:item tid=\"%i\" />\n") at asprintf_chk.c:32 #3 0xb71c7ada in ?? () from /usr/lib/vlc/plugins/access/libfilesystem_plugin.so #4 0xb748d3c4 in AStreamRefillBlock () from /usr/lib/libvlccore.so.8 #5 0xb748e4b9 in AStreamReadBlock () from /usr/lib/libvlccore.so.8 #6 0xb748f2d3 in stream_Read () from /usr/lib/libvlccore.so.8 #7 0xb6a01945 in ?? () from /usr/lib/vlc/plugins/stream_filter/librecord_plugin.so #8 0xb748f2d3 in stream_Read () from /usr/lib/libvlccore.so.8 #9 0xb67a6f70 in ?? () from /usr/lib/vlc/plugins/misc/libxml_plugin.so #10 0xb6c92dd3 in xmlParserInputBufferGrow () from /usr/lib/i386-linux-gnu/libxml2.so.2 #11 0xb6d17414 in ?? () from /usr/lib/i386-linux-gnu/libxml2.so.2 #12 0xb6d185ba in ?? () from /usr/lib/i386-linux-gnu/libxml2.so.2 #13 0xb6d18c9e in xmlTextReaderExpand () from /usr/lib/i386-linux-gnu/libxml2.so.2 #14 0xb6d1ba5d in xmlTextReaderRead () from /usr/lib/i386-linux-gnu/libxml2.so.2 #15 0xb67a6e54 in ?? () from /usr/lib/vlc/plugins/misc/libxml_plugin.so #16 0xb680365b in parse_tracklist_node () from /usr/lib/vlc/plugins/demux/libplaylist_plugin.so #17 0xb6803390 in Demux () from /usr/lib/vlc/plugins/demux/libplaylist_plugin.so #18 0xb7486ccc in MainLoop () from /usr/lib/libvlccore.so.8 #19 0xb74878d4 in Run () from /usr/lib/libvlccore.so.8 #20 0xb770fefb in start_thread (arg=0xb58f1b40) at pthread_create.c:309 #21 0xb7641ede in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:129