[x264-devel] hyperthreading and latency

[aviad rozenhek]

I have an issue where hyperthreading causes increased latency in x264,
without improving performance.
when threads are set to auto on my i7-920, latency is increased by 200ms
compared to when I set i-threads to be 4.
I noticed that pthread_num_processors_np() returns 8, even though there are
only 4 cores on that cpu (8 is the number of "threads" on that CPU)
the question is, does using 12 threads (8 * 1.5 factor) instead of 6 (4 *
1.5 factor) make sense on a 4 core system?
I think the answer is no and that the default value of X264_THREADS_AUTO
could work even better on hyper-threaded systems if hyper-threading are not
considered an actual CPU.

-- 
Aviad Rozenhek
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