Afaik the clflush instruction isn't really meant for optimization. It evinces data from all cache levels (so even from L3), which means it's only useful for dat

Afaik the clflush instruction isn't really meant for optimization. It evinces data from all cache levels (so even from L3), which means it's only useful for data you know you won't ever need again. I think the CPU is good enough at flushing that data that additional hints won't improve performance much.