math/big: more conservative use of lock for divisor table
Minor performance impact running sequentially:
benchmark old ns/op new ns/op delta
BenchmarkString10Base2 389 391 +0.51%
BenchmarkString100Base2 1530 1534 +0.26%
BenchmarkString1000Base2 11789 11787 -0.02%
BenchmarkString10000Base2 111443 112030 +0.53%
BenchmarkString100000Base2
1017483 1015347 -0.21%
BenchmarkString10Base8 339 344 +1.47%
BenchmarkString100Base8 753 756 +0.40%
BenchmarkString1000Base8 4618 4641 +0.50%
BenchmarkString10000Base8 43217 43534 +0.73%
BenchmarkString100000Base8 397518 400602 +0.78%
BenchmarkString10Base10 630 630 +0.00%
BenchmarkString100Base10 1975 1960 -0.76%
BenchmarkString1000Base10 10179 10174 -0.05%
BenchmarkString10000Base10 44527 44416 -0.25%
BenchmarkString100000Base10
14404694 14425308 +0.14%
BenchmarkString10Base16 283 288 +1.77%
BenchmarkString100Base16 597 598 +0.17%
BenchmarkString1000Base16 3189 3186 -0.09%
BenchmarkString10000Base16 29403 29364 -0.13%
BenchmarkString100000Base16 265657 265587 -0.03%
Note that due to other improvements (faster assembly routines,
better code generation by compiler), these benchmarks now run
up to 37% faster than they used to at the last time measured (1/9/2012).
Minor performance impact for StringPiParallel running in parallel:
Current CL but with Lock/Unlock commented out (removed):
BenchmarkStringPiParallel 5000 343581 ns/op
BenchmarkStringPiParallel-2 10000 184511 ns/op
BenchmarkStringPiParallel-3 10000 129768 ns/op
BenchmarkStringPiParallel-4 10000 102326 ns/op
Current CL:
BenchmarkStringPiParallel 5000 345169 ns/op
BenchmarkStringPiParallel-2 10000 185827 ns/op
BenchmarkStringPiParallel-3 10000 131168 ns/op
BenchmarkStringPiParallel-4 10000 102353 ns/op
Fixes #4218.
R=dvyukov, michael.jones, dave
CC=golang-dev
https://golang.org/cl/
6643053