[mythtv-users] Mythbackend high cpu?

[Joseph Fry]

>
>
> >> Is anyone else seeing extremely high CPU usage on their backend when
> >> playing back *any* content on a remote front end? I just noticed that
> >> during playback, the CPU usage of my backend stays around 175-200% on
> >> a 2 x Dual core AMD system. I can't imagine what it would be doing
> >> other than just streaming the file, is anyone else seeing this, or can
> >> explain it?
> >>
> >> I am on close to current master:
> >>
> >> MythTV Version : v0.26-pre-629-g181641a-dirty
> >> MythTV Branch : master
> >> Network Protocol : 75
> >> Library API : 0.26.20120614-1
> >> QT Version : 4.6.3
> >> Options compiled in:
> >>  linux profile use_hidesyms using_alsa using_oss using_backend
> >> using_bindings_perl using_bindings_python using_bindings_php using_dvb
> >> using_frontend using_hdhomerun using_ceton using_hdpvr using_iptv
> >> using_ivtv using_joystick_menu using_libcrypto using_libdns_sd
> >> using_libxml2 using_lirc using_mheg using_opengl_video using_qtwebkit
> >> using_qtscript using_qtdbus using_v4l2 using_v4l1 using_x11
> >> using_xrandr using_bindings_perl using_bindings_python
> >> using_bindings_php using_mythtranscode using_opengl
> >> using_ffmpeg_threads using_live using_mheg using_libxml2
> >
> > Hmmm....looks like it may have been a memory leak of some sort, I
> > started getting OOM killers and lots of swapping. I'll keep an eye on
> > it and see if it happens again.
> >
>
> I love talking to myself. Now with one frontend playing back and two
> recordings (1 HDHR and 1 HD-PVR on a slave BE) the BE CPU is over
> 250%. Lots of free memory (overall system memory is 8GB), so the OOM
> doesn't explain it.
>
>
The only things I can think of that MAY cause excessive CPU usage on the
backend, explicitly during playback/recording are:

1. Jobs (transcode/commercial flagging)
2. Degraded software RAID array.
3. non-DMA disk IO.
4. Encrypted/compressed drive
5. non-DMA network controller, or some on chipset NIC and a really horrible
network causing a ton of errors?

First try doing a couple of IO intensive tasks to confirm if it's mythtv
(perhaps use VLC to stream from the HDHR to a file?).  I suspect it's
something on the system itself, not mythtv.

If I am right I would start by verifying all RAID arrays are clean, and if
all looks good, do a full shutdown.  Then disconnect power and let it sit
for 15 minutes so any charged caps can dissipate before plugging in and
turning on.  This has fixed countless weird issues for me in the past,
primarily with NIC's that support WOL.  Seems as though many components of
your system don't truly reset anymore until the power is cut completely.

Good luck
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.mythtv.org/pipermail/mythtv-users/attachments/20120618/327442d8/attachment.html>