internal/bytealg: optimize cmpbody for ppc64le/ppc64
Vectorize the cmpbody loop for bytes of size greater than or equal
to 32 on both POWER8(LE and BE) and POWER9(LE and BE) and improve
performance of smaller size compares
Performance improves for most sizes with this change on POWER8, 9
and POWER10. For the very small sizes (upto 8) the overhead of
calling function starts to impact performance.
POWER9:
name old time/op new time/op delta
BytesCompare/1 4.60ns ± 0% 5.49ns ± 0% +19.27%
BytesCompare/2 4.68ns ± 0% 5.46ns ± 0% +16.71%
BytesCompare/4 6.58ns ± 0% 5.49ns ± 0% -16.58%
BytesCompare/8 4.89ns ± 0% 5.46ns ± 0% +11.64%
BytesCompare/16 5.21ns ± 0% 4.96ns ± 0% -4.70%
BytesCompare/32 5.09ns ± 0% 4.98ns ± 0% -2.14%
BytesCompare/64 6.40ns ± 0% 5.96ns ± 0% -6.84%
BytesCompare/128 11.3ns ± 0% 8.1ns ± 0% -28.09%
BytesCompare/256 15.1ns ± 0% 12.8ns ± 0% -15.16%
BytesCompare/512 26.5ns ± 0% 23.3ns ± 5% -12.03%
BytesCompare/1024 50.2ns ± 0% 41.6ns ± 2% -17.01%
BytesCompare/2048 99.3ns ± 0% 86.5ns ± 0% -12.88%
Change-Id: I24f93b2910591e6829ddd8509aa6eeaa6355c609
Reviewed-on: https://go-review.googlesource.com/c/go/+/362797
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
Run-TryBot: Archana Ravindar <aravind5@in.ibm.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>