[mythtv-users] ffmpeg and multiple CPUs. Was: Should I be switching to 0.21?

[Tom Dexter]

On Mon, Apr 14, 2008 at 1:42 PM, John Drescher <drescherjm at gmail.com> wrote:
> >  >  However...and this is the interesting part...if I use ffmpeg but
>  >  >  switch the number of CPUs to 1 instead of 2 the performance of the two
>  >  >  is virtually identical.  It seems that, at least with my
>  >  >  hyper-threaded 3 Ghz P4, ffmpeg works much better with a single core.
>  >  >
>  You do realize hyperthereading can have a negative impact on
>  performance? I mean a single core P4 with hyperthreading may look like
>  two cores but it certianly is not. Hyperthreading works only because
>  the P4 had such a long pipeline that stalls occurred so frequently
>  (mispredicted branch ...) and in this case a second thread could be
>  executed where no ops would be inserted in the pipeline.
>
>  John
>
>
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Yes I'm aware of that.  When I first set up my frontend I tested both
ways and the performance is better with it enabled.

I just gave it another try and it still seems to be an improvement
having it enabled.

<rant>Don't even get me started about how pissed off I get at Dell
when I need to change a bios setting on that 4700C frontend...their
piece of crap bios is too stupid to display on my TV via DVI.  Since
the only two conventional monitors I have right now are two massive
21" CRTs, changing a bios setting means an ordeal of taking the
frontend totally out of service, carrying it around the house and
crawling around wrestling with wires...unreal</rant>

Tom