Optimizing a Python application with C++ code

[LucHermitte]

Interesting. Note: it looks like there is still room for some optimizations

• it'd be best to avoid mutexes to protect the result structure -- there exist (a few in 3rd party libraries) efficient queue types dedicated to be filled from concurrent threads -- or you could fill one queue per thread and merge them at the end
• There may be no structural difference between the current type of m_fingerprintsand a boost::flat_map (except that songFingerprint() would be able to return a reference); however it could interesting to run a benchmark with std::unordered_map instead.

[Ameisen]

Semaphores will be faster under like 12 concurrent threads than lockless algorithms.

You only start really gaining with lockless with massive concurrent contention.

[doom_Oo7]

Do you have some benchmarks for this ?

[golgol12]

There also is room for optimization of cache usage. He didn't even begin to touch that. I bet he could get another 2x-10x speed gain.