[fpc-pascal] Effective memory allocation
kraybruno at bluewin.ch
Tue Nov 4 10:40:39 CET 2014
Relooking at your timings and mine, it appears that you allocate 10x my count of register-size count of items and require 10x the FillChar which you need to initialize your filter array.
My timing is about 80 ms and yours looks like 900 ms for 10x more register sized data, which look like the reasonable ratio since we may have difference in the way we get the timings (my timing routines beeing maybe a bit optimistic).
Here I think the speed limit is the time it takes to effectively transfer the data to RAM and that whether you have a FillChar or FillQWord that ends up beeing STOSB or STOSQ, that is fully cached inside the CPU thus the limiting factor is the time it takes to move the initialized CPU cached data to the RAM.
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