[PATCH] aarch64: Optimized memcmp for medium to large sizes

[Marcus Shawcroft]

On 2 February 2018 at 04:50, Siddhesh Poyarekar <siddhesh@sourceware.org> wrote:
> This improved memcmp provides a fast path for compares up to 16 bytes
> and then compares 16 bytes at a time, thus optimizing loads from both
> sources.  The glibc memcmp microbenchmark retains performance (with an
> error of ~1ns) for smaller compare sizes and reduces up to 31% of
> execution time for compares up to 4K on the APM Mustang.  On Qualcomm
> Falkor this improves to almost 48%, i.e. it is almost 2x improvement
> for sizes of 2K and above.


Hi Siddhesh,

Thanks for sharing the performance numbers on these two
u-architectures.  Have you looked at the impact of this patch on
performance of the various other aarch64 u-architectures?  If so
please share your findings.

Cheers
/Marcus