_doShuffle: Cython performance hint regarding GIL usage #476
Description
Am seeing the following performance hint from Cython regarding GIL usage in _doShuffle (due to exception raising). Would be good to address
performance hint: numcodecs/_shuffle.pyx:11:6: Exception check on '_doShuffle' will always require the GIL to be acquired. Possible solutions:
1. Declare the function as 'noexcept' if you control the definition and you're sure you don't want the function to raise exceptions.
2. Use an 'int' return type on the function to allow an error code to be returned.
performance hint: numcodecs/_shuffle.pyx:23:6: Exception check on '_doUnshuffle' will always require the GIL to be acquired. Possible solutions:
1. Declare the function as 'noexcept' if you control the definition and you're sure you don't want the function to raise exceptions.
2. Use an 'int' return type on the function to allow an error code to be returned.