Change the encoder's hash table values from int to int32.
Doing s/int/int32/ in "var table [maxTableSize]int" saves 64 KiB of
stack space that needed zero'ing. maxTableSize is 1<<14, or 16384.
The benchmarks show the biggest effect for small src lengths, or for
mostly uncompressible data such as the JPEG file (possibly because the
multiple-byte skipping means that the src is effectively short).
On amd64:
benchmark old MB/s new MB/s speedup
BenchmarkWordsEncode1e1-8 3.05 5.71 1.87x
BenchmarkWordsEncode1e2-8 26.98 44.87 1.66x
BenchmarkWordsEncode1e3-8 130.87 156.72 1.20x
BenchmarkWordsEncode1e4-8 162.48 180.89 1.11x
BenchmarkWordsEncode1e5-8 132.35 131.27 0.99x
BenchmarkWordsEncode1e6-8 159.97 158.49 0.99x
BenchmarkRandomEncode-8 12340.86 13485.69 1.09x
Benchmark_ZFlat0-8 329.92 329.17 1.00x
Benchmark_ZFlat1-8 165.06 164.46 1.00x
Benchmark_ZFlat2-8 8955.25 10530.49 1.18x
Benchmark_ZFlat3-8 47.79 80.06 1.68x
Benchmark_ZFlat4-8 2650.55 2732.00 1.03x
Benchmark_ZFlat5-8 336.52 334.94 1.00x
Benchmark_ZFlat6-8 147.99 145.85 0.99x
Benchmark_ZFlat7-8 136.32 137.20 1.01x
Benchmark_ZFlat8-8 153.03 152.15 0.99x
Benchmark_ZFlat9-8 133.18 131.74 0.99x
Benchmark_ZFlat10-8 376.02 378.28 1.01x
Benchmark_ZFlat11-8 224.16 216.81 0.97x
Thanks to Klaus Post for the original suggestion on
https://github.com/golang/snappy/pull/23 but I hesitate to accept that
pull request in its entirety as it makes many changes, some more
complicated than this separable, self-contained s/int/int32/ change.
1 file changed
