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Lynn Boger authored
The existing implementation for Equal and similar functions in the bytes package operate on one byte at at time. This performs poorly on ppc64/ppc64le especially when the byte buffers are large. This change improves those functions by loading and comparing double words where possible. The common code has been moved to a function that can be shared by the other functions in this file which perform the same type of comparison. Further optimizations are done for the case where >= 32 bytes are being compared. The new function memeqbody is used by memeq_varlen, Equal, and eqstring. When running the bytes test with -test.bench=Equal benchmark old MB/s new MB/s speedup BenchmarkEqual1 164.83 129.49 0.79x BenchmarkEqual6 563.51 445.47 0.79x BenchmarkEqual9 656.15 1099.00 1.67x BenchmarkEqual15 591.93 1024.30 1.73x BenchmarkEqual16 613.25 1914.12 3.12x BenchmarkEqual20 682.37 1687.04 2.47x BenchmarkEqual32 807.96 3843.29 4.76x BenchmarkEqual4K 1076.25 23280.51 21.63x BenchmarkEqual4M 1079.30 13120.14 12.16x BenchmarkEqual64M 1073.28 10876.92 10.13x It was determined that the degradation in the smaller byte tests were due to unfavorable code alignment of the single byte loop. Fixes #14368 Change-Id: I0dd87382c28887c70f4fbe80877a8ba03c31d7cd Reviewed-on: https://go-review.googlesource.com/20249Reviewed-by:
Minux Ma <minux@golang.org>
baec1487