A Dimecres 30 Juny 2004 23:47, Todd Miller va escriure:
There were a couple of other things I tried that resulted in additional small speedups, but the tactics I used were too horrible to reproduce here. The main one of interest is that all of the calls to NA_updateDataPtr seem to burn some time. However, I don't have any idea what one could do about that.
Francesc Alted had the same comment about NA_updateDataPtr a while ago. I tried to optimize it then but didn't get anywhere. NA_updateDataPtr() should be called at most once per extension function (more is unnecessary but not harmful) but needs to be called at least once as a consequence of the way the buffer protocol doesn't give locked pointers.
FYI I'm still refusing to call NA_updateDataPtr() in a spoecific part of my code that requires as much speed as possible. It works just fine from numarray 0.5 on (numarray 0.4 gave a segmentation fault on that). However, Todd already warned me about that and told me that this is unsafe. Nevertheless, I'm using the optimization for read-only purposes (i.e. they are not accessible to users) over numarray objects, and that *seems* to be safe (at least I did not have any single problem after numarray 0.5). I know that I'm walking on the cutting edge, but life is dangerous anyway ;). By the way, that optimization gives me a 70% of improvement during element access to NumArray elements. It would be very nice if you finally can achieve additional performance with your recent bet :). Good luck!, -- Francesc Alted