Emby server "Main" process high CPU when streaming LiveTV

[puithove 209]

First, let me be clear that I'm talking about the CPU utilization of the Emby server "Main" process - not the ffmpeg process which of course will use CPU if transcoding.  This affects LiveTV streams whether they are Direct Play or Transcode.

 

I've noticed previously that the Main process was running unusually high CPU when clients were active.  I hadn't really tracked it down to a pattern.

 

However, I just started experimenting with hardware transcoding using NVENC.  I happened to notice that CPU was still pretty high even when the ffmpeg-transcode log showed it was definitely using NVENC.  So then looking at TOP, I noticed that ffmpeg was quite low, and that the CPU usage was from "Main".  Typically I see "Main" process taking 200% CPU - here is an example:

  PID      TID    RUID        EUID         THR   SYSCPU    USRCPU     VGROW     RGROW    RDDSK     WRDSK    ST    EXC   S    CPUNR     CPU    CMD        1/3
 23032        -    emby        emby          22    2.66s    24.97s    124.9M    -5648K       0K     1292K    --      -   S        1    194%    Main
 23209        -    emby        emby          43    0.19s     7.28s     1164K     1304K       0K    13196K    --      -   S        8     52%    ffmpeg

So then bells went off.  I played a transcoded stream of a library item - and saw that the Main process was very low CPU, and also ffmpeg was very low (compared to a CPU transcode) - so all good there.

 

All the above was using the UWP version of ET with bandwidth setting set low in order to force transcoding.

 

Then I tried with the desktop version of ET to see what direct play would look like.  Even here, when not transcoding (so no ffmpeg process spun up), the "Main" process still ran up around 200% just to stream the Live TV.

   PID      TID    RUID        EUID         THR   SYSCPU    USRCPU     VGROW     RGROW    RDDSK     WRDSK    ST    EXC   S    CPUNR     CPU    CMD        1/3
 25852        -    emby        emby          30    2.43s    26.33s    675.1M    17456K       0K     1348K    --      -   S        5    206%    Main

Direct play of a Library file again showed low CPU on "Main".

 

So this seems to be all about LiveTV streaming.  With Direct Stream of Live TV, the only thing the "Main" process should have to be doing is sucking in the stream, and spitting it back out (with a pass through a temp file in the filesystem of course) so it shouldn't be using anywhere near that much CPU.

 

I'm thinking maybe an un-controlled loop or something maybe?

 

I'm attaching logs that show the activity from what I describe above.

UWP - ffmpeg-transcode-fab458f4-23c0-4fc2-af91-849abb726d73.txt

UWP - LiveTV - ffmpeg-transcode-5b72395c-973e-471c-8ca6-287b8b3218ec.txt

UWP - server-63621394469.txt

WinDesktop - server-63621395227.txt

[puithove 209]

Crap - just realized - this might not be a Linux-specific issue - probably should have posted it in the server testing area.

 

This was done using BETA .289, but I've noticed the high CPU going back several versions.

[Luke 42077]

Try removing all plugins and see if the issue persists. thanks !

[puithove 209]

I should have known LOL...  Ok, fair point.  The issue persists with NO plugins.  Here's a log after removing them all.

   PID      TID    RUID        EUID         THR   SYSCPU    USRCPU     VGROW     RGROW    RDDSK     WRDSK    ST    EXC   S    CPUNR     CPU    CMD        1/3
 28317        -    emby        emby          21    2.28s    23.91s        0K        4K       0K     1208K    --      -   S       11    200%    Main

server-63621396644.txt

[saed 6]

I got confused as a post

Edited January 31, 2017 by saed