[mythtv-commits] Ticket #2723: High CPU usage by mythfrontend

[MythTV]

#2723: High CPU usage by mythfrontend
-----------------------------------+----------------------------------------
 Reporter:  mythtv at merkx.demon.nl  |       Owner:  ijr    
     Type:  defect                 |      Status:  new    
 Priority:  minor                  |   Milestone:  unknown
Component:  mythtv                 |     Version:  0.20   
 Severity:  medium                 |  
-----------------------------------+----------------------------------------
 Hi,

 I saw a thread some time ago on the ivtv-devel list about high CPU usage
 of mythfrontend. This was thought to be related to a newer revision of the
 ivtv driver, but after observing the behaviour of my own system for some
 time, I think it is not.

 When playing a recording, mythfrontend uses approx 40% CPU:

   PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
  8429 mythtv    15   0  266m  98m  17m S   43  5.2  86:53.02 mythfrontend
  2746 root      18   0  286m  15m 8656 S    1  0.8   7:10.35 mythbackend

 However, even when I pause the playback, the CPU usage does _not_ change.
 It remains at approx 40%.

 An strace of the mythfrontend process reveals the following:

 Process 8429 attached - interrupt to quit
 restart_syscall(<... resuming interrupted call ...>) = 0
 ioctl(6, FIONREAD, [0])                 = 0
 write(7, "\0", 1)                       = 1
 gettimeofday({1164405083, 432439}, NULL) = 0
 ioctl(3, FIONREAD, [0])                 = 0
 gettimeofday({1164405083, 432924}, NULL) = 0
 select(22, [3 6 9 21], [], [], {0, 0})  = 1 (in [6], left {0, 0})
 read(6, "\0", 1)                        = 1
 gettimeofday({1164405083, 433716}, NULL) = 0
 nanosleep({0, 10000000}, NULL)          = 0
 ioctl(6, FIONREAD, [0])                 = 0
 write(7, "\0", 1)                       = 1
 gettimeofday({1164405083, 447846}, NULL) = 0
 ioctl(3, FIONREAD, [0])                 = 0
 gettimeofday({1164405083, 448017}, NULL) = 0
 select(22, [3 6 9 21], [], [], {0, 0})  = 1 (in [6], left {0, 0})
 read(6, "\0", 1)                        = 1
 gettimeofday({1164405083, 448287}, NULL) = 0
 gettimeofday({1164405083, 448378}, NULL) = 0
 ioctl(3, FIONREAD, [0])                 = 0
 gettimeofday({1164405083, 448530}, NULL) = 0
 select(22, [3 6 9 21], [], [], {0, 0})  = 0 (Timeout)
 gettimeofday({1164405083, 448689}, NULL) = 0
 gettimeofday({1164405083, 448834}, NULL) = 0
 ioctl(3, FIONREAD, [0])                 = 0
 gettimeofday({1164405083, 448985}, NULL) = 0
 select(22, [3 6 9 21], [], [], {0, 0})  = 0 (Timeout)
 gettimeofday({1164405083, 449144}, NULL) = 0
 nanosleep({0, 10000000}, NULL)          = 0
 ioctl(6, FIONREAD, [0])                 = 0
 write(7, "\0", 1)                       = 1
 gettimeofday({1164405083, 459767}, NULL) = 0
 ioctl(3, FIONREAD, [0])                 = 0
 gettimeofday({1164405083, 459920}, NULL) = 0
 select(22, [3 6 9 21], [], [], {0, 0})  = 1 (in [6], left {0, 0})
 read(6, "\0", 1)                        = 1
 gettimeofday({1164405083, 460204}, NULL) = 0
 nanosleep({0, 10000000}, NULL)          = 0
 ioctl(6, FIONREAD, [0])                 = 0
 write(7, "\0", 1)                       = 1
 gettimeofday({1164405083, 506219}, NULL) = 0
 ioctl(3, FIONREAD, [0])                 = 0
 gettimeofday({1164405083, 506707}, NULL) = 0

 This just on and on and on and seems to be burning quite a few CPU cyles
 for nothing...

 My setup is quite specific, so perhaps it is related: I'm using blueproxy
 to connect a simple VS2005 app on my PDA over bluetooth to the telnet
 interface of mythfrontend (which does absolutely nothing until a key is
 pressed; it even closes the socket after 30sec)

 Is this reproducible by others?

-- 
Ticket URL: <http://svn.mythtv.org/trac/ticket/2723>
MythTV <http://www.mythtv.org/>
MythTV