[mythtv-commits] Ticket #13072: Schedule busy looping with sched_sleep of 0

[MythTV]

#13072: Schedule busy looping with sched_sleep of 0
--------------------------------------+---------------------
     Reporter:  lucylangthorne55@…    |      Owner:  gigem
         Type:  Bug Report - General  |     Status:  new
     Priority:  minor                 |  Milestone:  unknown
    Component:  MythTV - Scheduling   |    Version:  0.28.0
     Severity:  medium                |   Keywords:
Ticket locked:  0                     |
--------------------------------------+---------------------
 Setup: 0.28.0+fixes.20170715.eef6a480b0-0ubuntu3 with master, one slave,
 mythweb frontend.

 Several times a day the scheduler runs 100% even though disks and mysql
 are idle.

 It appears that sched_sleep has becomes 0 while a recording is about to
 start (around line 2040). This then causes continuous scheduling since it
 remains at zero so does not sleep and re-loops hundreds of times a second.

 Strangely, the s2n only appears to decrease every few seconds whereas I
 expect it to be per second.

 The busy looping appears to be responsible for an overall unresponsive
 system (can't start frontend), possibly due to a lock held.

 I suspect altering sched_sleep from max(...,0) to max(...,1000) (around
 line 2019) to ensure a minimum sleep of a second would help.

--
Ticket URL: <https://code.mythtv.org/trac/ticket/13072>
MythTV <http://www.mythtv.org>
MythTV Media Center