There was a small typo in the comment before the Stable function.
Change-Id: Ia6fa5272aa7869124a637d2eeda81c4f35ef46c8
Reviewed-on: https://go-review.googlesource.com/4201
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
For some cases we can ensure the correct order of elements in two
instead of three comparisons. It is unnecessary to compare m0 and
m1 again if m2 and m1 are not swapped.
benchmark old ns/op new ns/op delta
BenchmarkSortString1K 302721 299590 -1.03%
BenchmarkSortInt1K 124055 123215 -0.68%
BenchmarkSortInt64K 12291522 12203402 -0.72%
BenchmarkSort1e2 58027 57111 -1.58%
BenchmarkSort1e4 12426805 12341761 -0.68%
BenchmarkSort1e6 1966250030 1960557883 -0.29%
Change-Id: I2b17ff8dee310ec9ab92a6f569a95932538768a9
Reviewed-on: https://go-review.googlesource.com/2614
Reviewed-by: Robert Griesemer <gri@golang.org>
Use direct binary insertion instead of recursive calls to symMerge
when one of the blocks has only one element.
benchmark old ns/op new ns/op delta
BenchmarkStableString1K 421999 397629 -5.77%
BenchmarkStableInt1K 123422 120592 -2.29%
BenchmarkStableInt64K 9629094 9620200 -0.09%
BenchmarkStable1e2 123089 120209 -2.34%
BenchmarkStable1e4 39505228 36870029 -6.67%
BenchmarkStable1e6 8196612367 7630840157 -6.90%
Change-Id: I49905a909e8595cfa05920ccf9aa00a8f3036110
Reviewed-on: https://go-review.googlesource.com/2219
Reviewed-by: Robert Griesemer <gri@golang.org>
Move the checks for empty rotate changes
from the beginning of rotate to the callers.
Remove additional variable p used instead of existing m with same value.
Remove special casing of equal ranges (i==j) to exit early as no
work is saved vs checking (i!=j) and making a single
swapRange call if this is false.
benchmark old ns/op new ns/op delta
BenchmarkStableString1K 417195 425218 +1.92%
BenchmarkStableInt1K 126661 124498 -1.71%
BenchmarkStableInt64K 10365014 10417438 +0.51%
BenchmarkStable1e2 132151 130648 -1.14%
BenchmarkStable1e4 42027428 40812649 -2.89%
BenchmarkStable1e6 8524772364 8430192391 -1.11%
Change-Id: Ia7642e9d31408496970c700f5843d53cc3ebe817
Reviewed-on: https://go-review.googlesource.com/2100
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Move the symMerge recursion stopping condition
from the beginning of symMerge to the callers.
This halves the number of calls to symMerge
while running 'go test sort'.
benchmark old ns/op new ns/op delta
BenchmarkStable1e6 8358117060 7954143849 -4.83%
BenchmarkStable1e4 40116117 38583285 -3.82%
BenchmarkStableInt1K 119150 115182 -3.33%
BenchmarkStableInt64K 9799845 9515475 -2.90%
BenchmarkStableString1K 388901 393516 +1.19%
BenchmarkStable1e2 124917 123618 -1.04%
Change-Id: I7ba2ca277f213b076fe6830e1139edb47ac53800
Reviewed-on: https://go-review.googlesource.com/1820
Reviewed-by: Robert Griesemer <gri@golang.org>
