Max 50% usage on dual-core CPU

Max 50% usage on dual-core CPU

[Chris Stanley]

I'm working with ffmpeg which uses Pthreads-w32 in Windows XP Pro SP2. 
I've used both Pthreads-w32 2.8.0 and 2.9.0 (which as far as I can tell 
doesn't exist, but is bundled with the Celtic Druid ffmpeg binaries 
nonetheless).

When using a single-core system (Celeron 2.5Ghz), everything is fine and 
ffmpeg/Pthreads-w32 eagerly uses 97-99% of my CPU.  But when I move the 
same code to a dual-core system (P4 3Ghz), it will never exceed exactly 
50% of the CPU.  By default it uses both cores at about 20/30.  If I 
change the affinity and restrict it to one core, then it uses the whole 
thing but again won't exceed exactly 50% of the total CPU.  I get the 
same results reading from and writing to a flash drive, so I don't think 
it's an I/O bottleneck.

I'm posting this to the ffmpeg list as well, but it seems like this 
could be something related to Pthreads-w32.  Does anyone have any 
thoughts about what might be going on?

Thanks!

-- 

Chris Stanley

Systems Administrator          cstanley@cctv.org
                                Office 802-862-1645, x11
Center for Media & Democracy   Mobile 802-324-8415
                                Fax    802-860-2370
294 North Winooski Ave         IM     ChrisStanleyCCTV
Burlington, VT 05401           http://www.cctv.org/

Re: Max 50% usage on dual-core CPU

[Chris Stanley]

I got a reply back from the other list and it was an ffmpeg issue with 
an easy fix.  Sorry for the bother, thanks!

--

Chris Stanley

Systems Administrator          cstanley@cctv.org
                                Office 802-862-1645, x11
Center for Media & Democracy   Mobile 802-324-8415
                                Fax    802-860-2370
294 North Winooski Ave         IM     ChrisStanleyCCTV
Burlington, VT 05401           http://www.cctv.org/


Chris Stanley wrote:
> I'm working with ffmpeg which uses Pthreads-w32 in Windows XP Pro SP2. 
> I've used both Pthreads-w32 2.8.0 and 2.9.0 (which as far as I can tell 
> doesn't exist, but is bundled with the Celtic Druid ffmpeg binaries 
> nonetheless).
> 
> When using a single-core system (Celeron 2.5Ghz), everything is fine and 
> ffmpeg/Pthreads-w32 eagerly uses 97-99% of my CPU.  But when I move the 
> same code to a dual-core system (P4 3Ghz), it will never exceed exactly 
> 50% of the CPU.  By default it uses both cores at about 20/30.  If I 
> change the affinity and restrict it to one core, then it uses the whole 
> thing but again won't exceed exactly 50% of the total CPU.  I get the 
> same results reading from and writing to a flash drive, so I don't think 
> it's an I/O bottleneck.
> 
> I'm posting this to the ffmpeg list as well, but it seems like this 
> could be something related to Pthreads-w32.  Does anyone have any 
> thoughts about what might be going on?
> 
> Thanks!
>