[mythtv-commits] Ticket #13170: Restore realtime priority capability for vsync thread

MythTV noreply at mythtv.org
Sat Nov 11 22:11:50 UTC 2017


#13170: Restore realtime priority capability for vsync thread
-----------------------------------+------------------------------
 Reporter:  Doug Larrick <doug@…>  |          Owner:  pbennett
     Type:  Patch - Feature        |         Status:  assigned
 Priority:  minor                  |      Milestone:  needs_triage
Component:  Ports - rPi            |        Version:  Master Head
 Severity:  medium                 |     Resolution:
 Keywords:                         |  Ticket locked:  0
-----------------------------------+------------------------------

Comment (by Doug Larrick <doug@…>):

 Today I've discovered that part of the reason Std.Dev is larger for RPi
 than for laptop is that VideoOutputOmx::Show takes a variable amount of
 time. The Jitterometer (MythPlayer::output_jmeter) is called after the
 call to Show(). If I move the call to the jitterometer to before the
 call(s) to Show() it reports less jitter overall -- and a (slightly)
 clearer advantage to realtime threads:

 Realtime off:
 {{{
 FPS:   29.98 Mean: 33356 Std.Dev:  4155 Min/Max:  6988/50045 CPUs: 11% 13%
 9% 2%
 FPS:   30.11 Mean: 33213 Std.Dev:  4165 Min/Max: 11498/50050 CPUs: 4% 6%
 7% 4%
 FPS:   29.86 Mean: 33494 Std.Dev:  4068 Min/Max:  8038/50050 CPUs: 3% 11%
 5% 8%
 FPS:   29.98 Mean: 33356 Std.Dev:   789 Min/Max: 27606/39109 CPUs: 5% 9%
 9% 6%
 FPS:   29.98 Mean: 33355 Std.Dev:  2283 Min/Max: 17689/50048 CPUs: 6% 9%
 10% 8%
 FPS:   29.86 Mean: 33493 Std.Dev:  3899 Min/Max: 18091/50048 CPUs: 0% 11%
 8% 7%
 FPS:   30.11 Mean: 33215 Std.Dev:  3996 Min/Max:  8536/50049 CPUs: 3% 10%
 15% 2%
 FPS:   29.98 Mean: 33356 Std.Dev:  3995 Min/Max: 19602/50048 CPUs: 2% 6%
 10% 11%
 FPS:   29.98 Mean: 33356 Std.Dev:  1517 Min/Max: 25537/41186 CPUs: 7% 0%
 11% 11%
 FPS:   29.98 Mean: 33355 Std.Dev:  3537 Min/Max: 15001/50044 CPUs: 10% 0%
 9% 9%
 }}}
 Realtime on:
 {{{
 FPS:   29.98 Mean: 33356 Std.Dev:  3310 Min/Max: 13170/54564 CPUs: 4% 3%
 9% 16%
 FPS:   29.98 Mean: 33355 Std.Dev:  2247 Min/Max: 20582/46136 CPUs: 4% 3%
 11% 10%
 FPS:   29.98 Mean: 33356 Std.Dev:  1772 Min/Max: 23100/43617 CPUs: 4% 5%
 12% 10%
 FPS:   29.98 Mean: 33355 Std.Dev:  2062 Min/Max: 22830/44132 CPUs: 9% 7%
 9% 8%
 FPS:   29.98 Mean: 33356 Std.Dev:  1639 Min/Max: 20939/45776 CPUs: 1% 13%
 7% 6%
 FPS:   29.98 Mean: 33355 Std.Dev:  1663 Min/Max: 24632/43413 CPUs: 4% 8%
 12% 8%
 FPS:   29.98 Mean: 33356 Std.Dev:  3123 Min/Max: 18933/47788 CPUs: 5% 8%
 9% 8%
 FPS:   29.98 Mean: 33356 Std.Dev:  1598 Min/Max: 23257/43468 CPUs: 8% 6%
 7% 10%
 FPS:   29.98 Mean: 33356 Std.Dev:  2780 Min/Max: 19303/47420 CPUs: 8% 6%
 7% 13%
 FPS:   29.89 Mean: 33451 Std.Dev:  2600 Min/Max: 19417/47303 CPUs: 8% 8%
 8% 7%
 }}}

 I do wonder why the OMX call is adding jitter.

--
Ticket URL: <https://code.mythtv.org/trac/ticket/13170#comment:10>
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