[mythtv-commits] Ticket #11255: Change MythTimer to use monotonic clock

[MythTV]

#11255: Change MythTimer to use monotonic clock
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 Reporter:  Rune Petersen <rune@…>  |           Type:  Patch - Feature
   Status:  new                     |       Priority:  minor
Milestone:  unknown                 |      Component:  MythTV - General
  Version:  0.26-fixes              |       Severity:  medium
 Keywords:  performance             |  Ticket locked:  0
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 Currently MythTimer is implemented using QTime which relies on system time
 and timezone conversion have the following problems:
  - imprecise if system time is changed
  - imprecise if if a change to/from DST happens


 The patch uses QElapsedTimer instead of QTime.
 QElapsedTimer relies on monotonic clock, "get ticks" or similar.

 Known problems with this patch:
  - QElapsedTimer requires QT 4.7 (what is currently the minimum
 requirement?)
  - addMSecs() cannot be implemented with QElapsedTimer, but then again the
 current implementation is a no-op.


 This patch reduces CPU usage by ~5% on a 700MHz Cortex-A9 when recording
 DVB HD content.

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Ticket URL: <http://code.mythtv.org/trac/ticket/11255>
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