Klaus Post b212c68b90 hash/crc32: use slicing by 8 for Castagnoli and smaller sizes ... This adds "slicing by 8" optimization to Castagnoli tables which will speed up CRC32 calculation on systems without asssembler, which are all but AMD64. In my tests, it is faster to use "slicing by 8" for sizes all down to 16 bytes, so the switchover point has been adjusted. There are no benchmarks for small sizes, so I have added one for 40 bytes, as well as one for bigger sizes (32KB). Castagnoli, No assembler, 40 Byte payload: (before, after) BenchmarkCastagnoli40B-4 10000000 161 ns/op 246.94 MB/s BenchmarkCastagnoli40B-4 20000000 100 ns/op 398.01 MB/s Castagnoli, No assembler, 32KB payload: (before, after) BenchmarkCastagnoli32KB-4 10000 115426 ns/op 283.89 MB/s BenchmarkCastagnoli32KB-4 30000 45171 ns/op 725.41 MB/s IEEE, No assembler, 1KB payload: (before, after) BenchmarkCrc1KB-4 500000 3604 ns/op 284.10 MB/s BenchmarkCrc1KB-4 1000000 1463 ns/op 699.79 MB/s Compared: benchmark old ns/op new ns/op delta BenchmarkCastagnoli40B-4 161 100 -37.89% BenchmarkCastagnoli32KB-4 115426 45171 -60.87% BenchmarkCrc1KB-4 3604 1463 -59.41% benchmark old MB/s new MB/s speedup BenchmarkCastagnoli40B-4 246.94 398.01 1.61x BenchmarkCastagnoli32KB-4 283.89 725.41 2.56x BenchmarkCrc1KB-4 284.10 699.79 2.46x Change-Id: I303e4ec84e8d4dafd057d64c0e43deb2b498e968 Reviewed-on: https://go-review.googlesource.com/19335 Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>		2016-03-08 16:46:24 +00:00
..
adler32	hash/*: document the byte order used by the Sum methods	2015-09-10 03:34:23 +00:00
crc32	hash/crc32: use slicing by 8 for Castagnoli and smaller sizes	2016-03-08 16:46:24 +00:00
crc64	hash/*: document the byte order used by the Sum methods	2015-09-10 03:34:23 +00:00
fnv	hash/*: document the byte order used by the Sum methods	2015-09-10 03:34:23 +00:00
hash.go
test_cases.txt
test_gen.awk