AtTheAsylum
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This is getting interesting
I've just run a test of this on my Laptop (WinXP Pro, T2400 Core 2 Duo 1.83Ghz, 667Mhz FSB, 2MB cache).
Using the standard 'Generic (DivX) DTS/DD+ Copy' profile (ie: no multi thread) mencoder uses between 48 and 50% of the CPU. It never goes above 50.0% as you would expect. Also, it never uses more than 1 thread (according to Task Manager).
When I set threads to 2 and run the exact same test mencoder uses between 48 and 53% of the CPU and starts 3 threads. If I set threads to 4 the CPU stays between 48 and 53% and this time mencoder starts 5 threads.
Time to encode is about the same for all tests (ie: multi-thread offers no improvement).
At home I have an older Pentium 4 3.0Ghz with Hyperthreading running WinXP Pro. If I run the same tests on this PC, with no multithread the CPU sits between 48 and 50%. With threads set to 2 the CPU sits between 70 and 85%. Unfortunately I don't have thread counts nor timings for these tests. I'll redo them tonight and post an update.
So either mencoder has been designed to use Hyperthreading and not multi-cores (unlikely) or WinXP doesn't properly handle multi-core CPU's.
I've just run a test of this on my Laptop (WinXP Pro, T2400 Core 2 Duo 1.83Ghz, 667Mhz FSB, 2MB cache).
Using the standard 'Generic (DivX) DTS/DD+ Copy' profile (ie: no multi thread) mencoder uses between 48 and 50% of the CPU. It never goes above 50.0% as you would expect. Also, it never uses more than 1 thread (according to Task Manager).
When I set threads to 2 and run the exact same test mencoder uses between 48 and 53% of the CPU and starts 3 threads. If I set threads to 4 the CPU stays between 48 and 53% and this time mencoder starts 5 threads.
Time to encode is about the same for all tests (ie: multi-thread offers no improvement).
At home I have an older Pentium 4 3.0Ghz with Hyperthreading running WinXP Pro. If I run the same tests on this PC, with no multithread the CPU sits between 48 and 50%. With threads set to 2 the CPU sits between 70 and 85%. Unfortunately I don't have thread counts nor timings for these tests. I'll redo them tonight and post an update.
So either mencoder has been designed to use Hyperthreading and not multi-cores (unlikely) or WinXP doesn't properly handle multi-core CPU's.