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path: root/src/math/bits/bits_impl.go
AgeCommit message (Collapse)Author
2017-02-28math/bits: move left-over functionality from bits_impl.go to bits.goRobert Griesemer
Removes an extra function call for TrailingZeroes and thus may increase chances for inlining. Change-Id: Iefd8d4402dc89b64baf4e5c865eb3dadade623af Reviewed-on: https://go-review.googlesource.com/37613 Run-TryBot: Robert Griesemer <gri@golang.org> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-02-28math/bits: faster LeadingZeros and Len functionsRobert Griesemer
benchmark old ns/op new ns/op delta BenchmarkLeadingZeros-8 8.43 3.10 -63.23% BenchmarkLeadingZeros8-8 8.13 1.33 -83.64% BenchmarkLeadingZeros16-8 7.34 2.07 -71.80% BenchmarkLeadingZeros32-8 7.99 2.87 -64.08% BenchmarkLeadingZeros64-8 8.13 2.96 -63.59% Measured on 2.3 GHz Intel Core i7 running macOS 10.12.3. Change-Id: Id343531b408d42ac45f10c76f60e85bdb977f91e Reviewed-on: https://go-review.googlesource.com/37582 Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-02-28math/bits: faster TrailingZeroes8Robert Griesemer
For sizes > 8, the existing code is faster. benchmark old ns/op new ns/op delta BenchmarkTrailingZeros8-8 1.95 1.29 -33.85% Measured on 2.3 GHz Intel Core i7 running macOS 10.12.3. Change-Id: I6f3a33ec633a2c544ec29693c141f2f99335c745 Reviewed-on: https://go-review.googlesource.com/37581 Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-02-17math/bits: faster Rotate functions, added respective benchmarksRobert Griesemer
Measured on 2.3 GHz Intel Core i7, running maxOS 10.12.3. benchmark old ns/op new ns/op delta BenchmarkRotateLeft-8 7.87 7.00 -11.05% BenchmarkRotateLeft8-8 8.41 4.52 -46.25% BenchmarkRotateLeft16-8 8.07 4.55 -43.62% BenchmarkRotateLeft32-8 8.36 4.73 -43.42% BenchmarkRotateLeft64-8 7.93 4.78 -39.72% BenchmarkRotateRight-8 8.23 6.72 -18.35% BenchmarkRotateRight8-8 8.76 4.39 -49.89% BenchmarkRotateRight16-8 9.07 4.44 -51.05% BenchmarkRotateRight32-8 8.85 4.46 -49.60% BenchmarkRotateRight64-8 8.11 4.43 -45.38% Change-Id: I79ea1e9e6fc65f95794a91f860a911efed3aa8a1 Reviewed-on: https://go-review.googlesource.com/37219 Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2017-02-17math/bits: faster OnesCount, added respective benchmarksRobert Griesemer
Also: Changed Reverse/ReverseBytes implementations to use the same (smaller) masks as OnesCount. BenchmarkOnesCount-8 37.0 6.26 -83.08% BenchmarkOnesCount8-8 7.24 1.99 -72.51% BenchmarkOnesCount16-8 11.3 2.47 -78.14% BenchmarkOnesCount32-8 18.4 3.02 -83.59% BenchmarkOnesCount64-8 40.0 3.78 -90.55% BenchmarkReverse-8 6.69 6.22 -7.03% BenchmarkReverse8-8 1.64 1.64 +0.00% BenchmarkReverse16-8 2.26 2.18 -3.54% BenchmarkReverse32-8 2.88 2.87 -0.35% BenchmarkReverse64-8 5.64 4.34 -23.05% BenchmarkReverseBytes-8 2.48 2.17 -12.50% BenchmarkReverseBytes16-8 0.63 0.95 +50.79% BenchmarkReverseBytes32-8 1.13 1.24 +9.73% BenchmarkReverseBytes64-8 2.50 2.16 -13.60% OnesCount-8 37.0ns ± 0% 6.3ns ± 0% ~ (p=1.000 n=1+1) OnesCount8-8 7.24ns ± 0% 1.99ns ± 0% ~ (p=1.000 n=1+1) OnesCount16-8 11.3ns ± 0% 2.5ns ± 0% ~ (p=1.000 n=1+1) OnesCount32-8 18.4ns ± 0% 3.0ns ± 0% ~ (p=1.000 n=1+1) OnesCount64-8 40.0ns ± 0% 3.8ns ± 0% ~ (p=1.000 n=1+1) Reverse-8 6.69ns ± 0% 6.22ns ± 0% ~ (p=1.000 n=1+1) Reverse8-8 1.64ns ± 0% 1.64ns ± 0% ~ (all samples are equal) Reverse16-8 2.26ns ± 0% 2.18ns ± 0% ~ (p=1.000 n=1+1) Reverse32-8 2.88ns ± 0% 2.87ns ± 0% ~ (p=1.000 n=1+1) Reverse64-8 5.64ns ± 0% 4.34ns ± 0% ~ (p=1.000 n=1+1) ReverseBytes-8 2.48ns ± 0% 2.17ns ± 0% ~ (p=1.000 n=1+1) ReverseBytes16-8 0.63ns ± 0% 0.95ns ± 0% ~ (p=1.000 n=1+1) ReverseBytes32-8 1.13ns ± 0% 1.24ns ± 0% ~ (p=1.000 n=1+1) ReverseBytes64-8 2.50ns ± 0% 2.16ns ± 0% ~ (p=1.000 n=1+1) Change-Id: I591b0ffc83fc3a42828256b6e5030f32c64f9497 Reviewed-on: https://go-review.googlesource.com/37218 Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2017-02-17math/bits: much faster ReverseBytes, added respective benchmarksRobert Griesemer
Measured on 2.3 GHz Intel Core i7, running maxOS 10.12.3. benchmark old ns/op new ns/op delta BenchmarkReverseBytes-8 11.4 3.51 -69.21% BenchmarkReverseBytes16-8 6.87 0.64 -90.68% BenchmarkReverseBytes32-8 7.79 0.65 -91.66% BenchmarkReverseBytes64-8 11.6 0.64 -94.48% name old time/op new time/op delta ReverseBytes-8 11.4ns ± 0% 3.5ns ± 0% ~ (p=1.000 n=1+1) ReverseBytes16-8 6.87ns ± 0% 0.64ns ± 0% ~ (p=1.000 n=1+1) ReverseBytes32-8 7.79ns ± 0% 0.65ns ± 0% ~ (p=1.000 n=1+1) ReverseBytes64-8 11.6ns ± 0% 0.6ns ± 0% ~ (p=1.000 n=1+1) Change-Id: I67b529652b3b613c61687e9e185e8d4ee40c51a2 Reviewed-on: https://go-review.googlesource.com/37211 Run-TryBot: Robert Griesemer <gri@golang.org> Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2017-02-17math/bits: much faster Reverse, added respective benchmarksRobert Griesemer
Measured on 2.3 GHz Intel Core i7, running maxOS 10.12.3. name old time/op new time/op delta Reverse-8 76.6ns ± 0% 8.1ns ± 0% ~ (p=1.000 n=1+1) Reverse8-8 12.6ns ± 0% 0.6ns ± 0% ~ (p=1.000 n=1+1) Reverse16-8 20.8ns ± 0% 0.6ns ± 0% ~ (p=1.000 n=1+1) Reverse32-8 36.5ns ± 0% 0.6ns ± 0% ~ (p=1.000 n=1+1) Reverse64-8 74.0ns ± 0% 6.4ns ± 0% ~ (p=1.000 n=1+1) benchmark old ns/op new ns/op delta BenchmarkReverse-8 76.6 8.07 -89.46% BenchmarkReverse8-8 12.6 0.64 -94.92% BenchmarkReverse16-8 20.8 0.64 -96.92% BenchmarkReverse32-8 36.5 0.64 -98.25% BenchmarkReverse64-8 74.0 6.38 -91.38% Change-Id: I6b99b10cee2f2babfe79342b50ee36a45a34da30 Reviewed-on: https://go-review.googlesource.com/37149 Run-TryBot: Robert Griesemer <gri@golang.org> Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2017-02-16math/bits: added package for bit-level counting and manipulationRobert Griesemer
Initial platform-independent implementation. For #18616. Change-Id: I4585c55b963101af9059c06c1b8a866cb384754c Reviewed-on: https://go-review.googlesource.com/36315 Reviewed-by: Keith Randall <khr@golang.org> Reviewed-by: Russ Cox <rsc@golang.org>
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