>Each ndarray does two mallocs, for the obj and buffer. These could be combined into 1 - just allocate the total size and do some pointer >arithmetic, then set OWNDATA to false.
So, that two mallocs has been mentioned in project introduction. I got that wrong.
>magnitude more time in inefficient loop selection and unnecessary writes to the FP control word?
loop selection, contribute around 2~3% in time. I implemented cache with PyThreadState_GetDict() but it didnt help.
Even generating prepopulated dict/list in code_generator/generate_umath.py is not helping,
Here, it the distribution of time, on addition operations. All memory related and BuildValue operations cost more than 7%, rest looping ones are around 2-3%:
- PyUFunc_AddititonTypeResolver(7.6%)
- SimpleBinaryOperationTypeResolver(6.2%)
- execute_legacy_ufunc_loop(20.7%)
- trivial_three_operand_loop(8.6%) ,this will be around 3.4% when pr #3521 get merged
- PYArray_NewFromDescr(7.3%)
- PyUFunc_DefaultLegacyInnerLoopSelector(2.5%)
- PyUFunc_GetPyValues(12.0%)
- PyArray_Return(14.3%)