On Mon, 2019-09-09 at 10:14 +0200, David Hildenbrand wrote: > On 07.09.19 19:25, Alexander Duyck wrote: > > From: Alexander Duyck <alexander.h.duyck@xxxxxxxxxxxxxxx> > > > > Change the logic used to generate randomness in the suffle path so that we > > can avoid cache line bouncing. The previous logic was sharing the offset > > and entropy word between all CPUs. As such this can result in cache line > > bouncing and will ultimately hurt performance when enabled. > > So, usually we perform such changes if there is real evidence. Do you > have any such performance numbers to back your claims? I don't have any numbers. From what I can tell the impact is small enough that this doesn't really have much impact. With that being the case I can probably just drop this patch. I will instead just use "rand & 1" in the 2nd patch to generate the return value which was what was previously done in add_to_free_area_random.
