[mythtv-users] Video jitter possibly cased by low cpu usage

Marius Schrecker marius.schrecker at lyse.net
Thu Dec 19 07:23:15 UTC 2013


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On Thursday, December 19, 2013 08:13 CET, Gary Buhrmaster <gary.buhrmaster at gmail.com> wrote:
 On Tue, Dec 17, 2013 at 8:42 AM, Marius Schrecker
wrote:
....
> The only things I don't uinderstand is why I should notice a further improvement when raising both cores

Unless you are setting process processor affinity, any process
might get dispatched onto any processor. If one processor is
running slower, and that is where MythTV gets dispatched....

Process affinity is an advanced topic, but can produce
dramatic benefits (or really bad results) depending on your
specific workload (and tuning).

Note that Linux has had "soft" affinity since (I think) 2.5.
That means that once a process is dispatched on a processor,
it will tend to stay on that processor, but only until "something
happens" to cause it to change to another (where it will tend
to stay for some period).
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http://www.mythtv.org/mailman/listinfo/mythtv-usersThanks for the reply Gary,

   but even when running at 800MHz, neither of the cores is stressed and can easily handle the video processing overhead (playback data indicates around 15% cpu usage at lowest frequency. Does each core have a dedicated bus that is throttled at lower cpu freqs?


 


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