[PATCH 1/2] aarch64,falkor: Ignore prefetcher hints for memmove tail

[Szabolcs Nagy]

On 03/05/18 18:52, Siddhesh Poyarekar wrote:
> The tail of the copy loops are unable to train the falkor hardware
> prefetcher because they load from a different base compared to the hot
> loop.  In this case avoid serializing the instructions by loading them
> into different registers.  Also peel the last iteration of the loop
> into the tail (and have them use different registers) since it gives
> better performance for medium sizes.
> 
> This results in performance improvements of between 3% and 20% over
> the current falkor implementation for sizes between 128 bytes and 1K
> on the memmove-walk benchmark, thus mostly covering the regressions
> seen against the generic memmove.
> 
> 	* sysdeps/aarch64/multiarch/memmove_falkor.S
> 	(__memmove_falkor): Use multiple registers to move data in
> 	loop tail.

OK to commit.