Found by running $ go run golang.org/x/tools/go/analysis/passes/nilness/cmd/nilness@latest std No actual bugs--other than one panic(nil)--but a few places where error nilness was unclear. Change-Id: Ia916ba30f46f29c1bcf928cc62280169b922463a Reviewed-on: https://go-review.googlesource.com/c/go/+/486675 Reviewed-by: Ian Lance Taylor <iant@google.com> Run-TryBot: Alan Donovan <adonovan@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Auto-Submit: Alan Donovan <adonovan@google.com>
Fixes the misuse of "a" vs "an", according to English grammatical expectations and using https://www.a-or-an.com/ Change-Id: I53ac724070e3ff3d33c304483fe72c023c7cda47 Reviewed-on: https://go-review.googlesource.com/c/go/+/480536 Run-TryBot: shuang cui <imcusg@gmail.com> Reviewed-by: Ian Lance Taylor <iant@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Auto-Submit: Ian Lance Taylor <iant@google.com> Run-TryBot: Ian Lance Taylor <iant@google.com> Reviewed-by: Michael Knyszek <mknyszek@google.com>
I noticed the one in path/filepath while reading the docs, and the other ones were found via some quick grepping. Change-Id: I386f2f74ef816a6d18aa2f58ee6b64dbd0147c9e Reviewed-on: https://go-review.googlesource.com/c/go/+/478795 Run-TryBot: Daniel Martí <mvdan@mvdan.cc> Reviewed-by: Heschi Kreinick <heschi@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@google.com>
This adds a new Buffer.AvailableBuffer method that returns an empty buffer with a possibly non-empty capacity for use with append-like APIs. The typical usage pattern is something like: b := bb.AvailableBuffer() b = appendValue(b, v) bb.Write(b) It allows logic combining append-like APIs with Buffer to avoid needing to allocate and manage buffers themselves and allows the append-like APIs to directly write into the Buffer. The Buffer.Write method uses the builtin copy function, which avoids copying bytes if the source and destination are identical. Thus, Buffer.Write is a constant-time call for this pattern. Performance: BenchmarkBufferAppendNoCopy 2.909 ns/op 5766942167.24 MB/s This benchmark should only be testing the cost of bookkeeping and never the copying of the input slice. Thus, the MB/s should be orders of magnitude faster than RAM. Fixes #53685 Change-Id: I0b41e54361339df309db8d03527689b123f99085 Reviewed-on: https://go-review.googlesource.com/c/go/+/474635 Run-TryBot: Joseph Tsai <joetsai@digital-static.net> Reviewed-by: Daniel Martí <mvdan@mvdan.cc> Reviewed-by: Cherry Mui <cherryyz@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Auto-Submit: Joseph Tsai <joetsai@digital-static.net> Reviewed-by: Ian Lance Taylor <iant@google.com>
Add bytealg.MakeNoZero that specially allocates a []byte without zeroing it. It assumes the caller will populate every byte. From within the bytes and strings packages, we can use bytealg.MakeNoZero in a way where our logic ensures that the entire slice is overwritten such that uninitialized bytes are never leaked to the end user. We use bytealg.MakeNoZero from within the following functions: * bytes.Join * bytes.Repeat * bytes.ToUpper * bytes.ToLower * strings.Builder.Grow The optimization in strings.Builder transitively benefits the following: * strings.Join * strings.Map * strings.Repeat * strings.ToUpper * strings.ToLower * strings.ToValidUTF8 * strings.Replace * any user logic that depends on strings.Builder This optimization is especially notable on large buffers that do not fit in the CPU cache, such that the cost of runtime.memclr and runtime.memmove are non-trivial since they are both limited by the relatively slow speed of physical RAM. Performance: RepeatLarge/256/1 66.0ns ± 3% 64.5ns ± 1% ~ (p=0.095 n=5+5) RepeatLarge/256/16 55.4ns ± 5% 53.1ns ± 3% -4.17% (p=0.016 n=5+5) RepeatLarge/512/1 95.5ns ± 7% 87.1ns ± 2% -8.78% (p=0.008 n=5+5) RepeatLarge/512/16 84.4ns ± 9% 76.2ns ± 5% -9.73% (p=0.016 n=5+5) RepeatLarge/1024/1 161ns ± 4% 144ns ± 7% -10.45% (p=0.016 n=5+5) RepeatLarge/1024/16 148ns ± 3% 141ns ± 5% ~ (p=0.095 n=5+5) RepeatLarge/2048/1 296ns ± 7% 288ns ± 5% ~ (p=0.841 n=5+5) RepeatLarge/2048/16 298ns ± 8% 281ns ± 5% ~ (p=0.151 n=5+5) RepeatLarge/4096/1 593ns ± 8% 539ns ± 8% -8.99% (p=0.032 n=5+5) RepeatLarge/4096/16 568ns ±12% 526ns ± 7% ~ (p=0.056 n=5+5) RepeatLarge/8192/1 1.15µs ± 8% 1.08µs ±12% ~ (p=0.095 n=5+5) RepeatLarge/8192/16 1.12µs ± 4% 1.07µs ± 7% ~ (p=0.310 n=5+5) RepeatLarge/8192/4097 1.77ns ± 1% 1.76ns ± 2% ~ (p=0.310 n=5+5) RepeatLarge/16384/1 2.06µs ± 7% 1.94µs ± 5% ~ (p=0.222 n=5+5) RepeatLarge/16384/16 2.02µs ± 4% 1.92µs ± 6% ~ (p=0.095 n=5+5) RepeatLarge/16384/4097 1.50µs ±15% 1.44µs ±11% ~ (p=0.802 n=5+5) RepeatLarge/32768/1 3.90µs ± 8% 3.65µs ±11% ~ (p=0.151 n=5+5) RepeatLarge/32768/16 3.92µs ±14% 3.68µs ±12% ~ (p=0.222 n=5+5) RepeatLarge/32768/4097 3.71µs ± 5% 3.43µs ± 4% -7.54% (p=0.032 n=5+5) RepeatLarge/65536/1 7.47µs ± 8% 6.88µs ± 9% ~ (p=0.056 n=5+5) RepeatLarge/65536/16 7.29µs ± 4% 6.74µs ± 6% -7.60% (p=0.016 n=5+5) RepeatLarge/65536/4097 7.90µs ±11% 6.34µs ± 5% -19.81% (p=0.008 n=5+5) RepeatLarge/131072/1 17.0µs ±18% 14.1µs ± 6% -17.32% (p=0.008 n=5+5) RepeatLarge/131072/16 15.2µs ± 2% 16.2µs ±17% ~ (p=0.151 n=5+5) RepeatLarge/131072/4097 15.7µs ± 6% 14.8µs ±11% ~ (p=0.095 n=5+5) RepeatLarge/262144/1 30.4µs ± 5% 31.4µs ±13% ~ (p=0.548 n=5+5) RepeatLarge/262144/16 30.1µs ± 4% 30.7µs ±11% ~ (p=1.000 n=5+5) RepeatLarge/262144/4097 31.2µs ± 7% 32.7µs ±13% ~ (p=0.310 n=5+5) RepeatLarge/524288/1 67.5µs ± 9% 63.7µs ± 3% ~ (p=0.095 n=5+5) RepeatLarge/524288/16 67.2µs ± 5% 62.9µs ± 6% ~ (p=0.151 n=5+5) RepeatLarge/524288/4097 65.5µs ± 4% 65.2µs ±18% ~ (p=0.548 n=5+5) RepeatLarge/1048576/1 141µs ± 6% 137µs ±14% ~ (p=0.421 n=5+5) RepeatLarge/1048576/16 140µs ± 2% 134µs ±11% ~ (p=0.222 n=5+5) RepeatLarge/1048576/4097 141µs ± 3% 134µs ±10% ~ (p=0.151 n=5+5) RepeatLarge/2097152/1 258µs ± 2% 271µs ±10% ~ (p=0.222 n=5+5) RepeatLarge/2097152/16 263µs ± 6% 273µs ± 9% ~ (p=0.151 n=5+5) RepeatLarge/2097152/4097 270µs ± 2% 277µs ± 6% ~ (p=0.690 n=5+5) RepeatLarge/4194304/1 684µs ± 3% 467µs ± 6% -31.69% (p=0.008 n=5+5) RepeatLarge/4194304/16 682µs ± 1% 471µs ± 7% -30.91% (p=0.008 n=5+5) RepeatLarge/4194304/4097 685µs ± 2% 465µs ±20% -32.12% (p=0.008 n=5+5) RepeatLarge/8388608/1 1.50ms ± 1% 1.16ms ± 8% -22.63% (p=0.008 n=5+5) RepeatLarge/8388608/16 1.50ms ± 2% 1.22ms ±17% -18.49% (p=0.008 n=5+5) RepeatLarge/8388608/4097 1.51ms ± 7% 1.33ms ±11% -11.56% (p=0.008 n=5+5) RepeatLarge/16777216/1 3.48ms ± 4% 2.66ms ±13% -23.76% (p=0.008 n=5+5) RepeatLarge/16777216/16 3.37ms ± 3% 2.57ms ±13% -23.72% (p=0.008 n=5+5) RepeatLarge/16777216/4097 3.38ms ± 9% 2.50ms ±11% -26.16% (p=0.008 n=5+5) RepeatLarge/33554432/1 7.74ms ± 1% 4.70ms ±19% -39.31% (p=0.016 n=4+5) RepeatLarge/33554432/16 7.90ms ± 4% 4.78ms ± 9% -39.50% (p=0.008 n=5+5) RepeatLarge/33554432/4097 7.80ms ± 2% 4.86ms ±11% -37.60% (p=0.008 n=5+5) RepeatLarge/67108864/1 16.4ms ± 3% 9.7ms ±15% -41.29% (p=0.008 n=5+5) RepeatLarge/67108864/16 16.5ms ± 1% 9.9ms ±15% -39.83% (p=0.008 n=5+5) RepeatLarge/67108864/4097 16.5ms ± 1% 11.0ms ±18% -32.95% (p=0.008 n=5+5) RepeatLarge/134217728/1 35.2ms ±12% 19.2ms ±10% -45.58% (p=0.008 n=5+5) RepeatLarge/134217728/16 34.6ms ± 6% 19.3ms ± 7% -44.07% (p=0.008 n=5+5) RepeatLarge/134217728/4097 33.2ms ± 2% 19.3ms ±14% -41.79% (p=0.008 n=5+5) RepeatLarge/268435456/1 70.9ms ± 2% 36.2ms ± 5% -48.87% (p=0.008 n=5+5) RepeatLarge/268435456/16 77.4ms ± 7% 36.1ms ± 8% -53.33% (p=0.008 n=5+5) RepeatLarge/268435456/4097 75.8ms ± 4% 37.0ms ± 4% -51.15% (p=0.008 n=5+5) RepeatLarge/536870912/1 163ms ±14% 77ms ± 9% -52.94% (p=0.008 n=5+5) RepeatLarge/536870912/16 156ms ± 4% 76ms ± 6% -51.42% (p=0.008 n=5+5) RepeatLarge/536870912/4097 151ms ± 2% 76ms ± 6% -49.64% (p=0.008 n=5+5) RepeatLarge/1073741824/1 293ms ± 5% 149ms ± 8% -49.18% (p=0.008 n=5+5) RepeatLarge/1073741824/16 308ms ± 9% 150ms ± 8% -51.19% (p=0.008 n=5+5) RepeatLarge/1073741824/4097 299ms ± 5% 151ms ± 6% -49.51% (p=0.008 n=5+5) Updates #57153 Change-Id: I024553b7e676d6da6408278109ac1fa8def0a802 Reviewed-on: https://go-review.googlesource.com/c/go/+/456336 Reviewed-by: Dmitri Shuralyov <dmitshur@google.com> Reviewed-by: Ian Lance Taylor <iant@google.com> Run-TryBot: Joseph Tsai <joetsai@digital-static.net> TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
Fixes #54386. Change-Id: I78747da337ed6129e4f7426dd0483a644bed82e3 Reviewed-on: https://go-review.googlesource.com/c/go/+/460216 TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Matthew Dempsky <mdempsky@google.com> Reviewed-by: Ian Lance Taylor <iant@google.com> Run-TryBot: hopehook <hopehook@golangcn.org> Auto-Submit: Ian Lance Taylor <iant@golang.org>
Change-Id: Ic93ad59119f3549c0f13c4f366f71e9d01b88c47 GitHub-Last-Rev: afb518047288976f440d3fe0d65923c1905a9b26 GitHub-Pull-Request: golang/go#57907 Reviewed-on: https://go-review.googlesource.com/c/go/+/462283 TryBot-Result: Gopher Robot <gobot@golang.org> Run-TryBot: Ian Lance Taylor <iant@google.com> Reviewed-by: Ian Lance Taylor <iant@google.com> Reviewed-by: Cherry Mui <cherryyz@google.com> Run-TryBot: Ian Lance Taylor <iant@golang.org> Auto-Submit: Ian Lance Taylor <iant@google.com>
Change-Id: I63181f6540fc1bfcfc988a16bf9fafbd3575cfdf GitHub-Last-Rev: d90528730a92a087866c1bfc227a0a0bf1cdffbe GitHub-Pull-Request: golang/go#57909 Reviewed-on: https://go-review.googlesource.com/c/go/+/462284 Reviewed-by: Ian Lance Taylor <iant@google.com> Run-TryBot: Ian Lance Taylor <iant@golang.org> Auto-Submit: Ian Lance Taylor <iant@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Run-TryBot: Ian Lance Taylor <iant@google.com> Reviewed-by: Cherry Mui <cherryyz@google.com>
When generating long strings or slices with Repeat we currently reuse intermediate states as a way to quickly build exponentially longer results. This works well as long as the intermediate states fit into the processor D-cache. If they don't we start thrashing the D-cache by reading in the whole intermediate state over and over on each iteration. Instead, once we reach a large enough intermediate state (that allows the memcpy operation to perform at peak) we cap the size of chunk of the state that is used as source for subsequent appends. This ensures that this smaller source chunk is always present in the D-cache, and the append operation does not need to read the state contents from memory. Currently the cap is set to 8KB, a number derived via experimentation to yield the highest performance across a a large range of result sizes. Slightly higher caps also produced similar results: 8KB was chosen as the smallest one in this performance plateau with the intention to minimize D-cache pollution. For result sizes larger than the fastest cache levels we get significantly higher performance compared to the current implementation: strings: name old speed new speed delta RepeatLarge/256/1-16 1.73GB/s ± 1% 1.73GB/s ± 0% ~ (p=0.556 n=5+4) RepeatLarge/256/16-16 2.02GB/s ± 0% 1.95GB/s ± 8% ~ (p=0.222 n=5+5) RepeatLarge/512/1-16 2.30GB/s ±13% 2.47GB/s ± 1% ~ (p=0.548 n=5+5) RepeatLarge/512/16-16 2.38GB/s ±16% 2.77GB/s ± 1% +16.27% (p=0.032 n=5+5) RepeatLarge/1024/1-16 3.17GB/s ± 1% 3.18GB/s ± 0% ~ (p=0.730 n=4+5) RepeatLarge/1024/16-16 3.39GB/s ± 2% 3.38GB/s ± 1% ~ (p=0.548 n=5+5) RepeatLarge/2048/1-16 3.32GB/s ± 2% 3.32GB/s ± 2% ~ (p=1.000 n=5+5) RepeatLarge/2048/16-16 3.41GB/s ± 4% 3.46GB/s ± 2% ~ (p=0.310 n=5+5) RepeatLarge/4096/1-16 3.60GB/s ± 4% 3.67GB/s ± 3% ~ (p=0.690 n=5+5) RepeatLarge/4096/16-16 3.74GB/s ± 3% 3.71GB/s ± 5% ~ (p=0.690 n=5+5) RepeatLarge/8192/1-16 3.94GB/s ± 4% 4.01GB/s ± 1% ~ (p=0.222 n=5+5) RepeatLarge/8192/16-16 3.94GB/s ± 6% 4.05GB/s ± 1% ~ (p=0.222 n=5+5) RepeatLarge/8192/4097-16 4.25GB/s ± 6% 4.32GB/s ± 3% ~ (p=0.690 n=5+5) RepeatLarge/16384/1-16 4.96GB/s ± 1% 5.02GB/s ± 2% ~ (p=0.421 n=5+5) RepeatLarge/16384/16-16 4.99GB/s ± 2% 5.07GB/s ± 1% ~ (p=0.421 n=5+5) RepeatLarge/16384/4097-16 5.15GB/s ± 3% 5.17GB/s ± 1% ~ (p=1.000 n=5+5) RepeatLarge/32768/1-16 5.44GB/s ± 2% 5.42GB/s ± 1% ~ (p=0.841 n=5+5) RepeatLarge/32768/16-16 5.46GB/s ± 4% 5.44GB/s ± 1% ~ (p=0.905 n=5+4) RepeatLarge/32768/4097-16 4.84GB/s ± 2% 4.59GB/s ±12% -5.05% (p=0.032 n=5+5) RepeatLarge/65536/1-16 5.85GB/s ± 0% 5.84GB/s ± 1% ~ (p=0.690 n=5+5) RepeatLarge/65536/16-16 5.81GB/s ± 2% 5.84GB/s ± 2% ~ (p=0.421 n=5+5) RepeatLarge/65536/4097-16 5.38GB/s ± 6% 5.45GB/s ± 1% ~ (p=1.000 n=5+5) RepeatLarge/131072/1-16 6.20GB/s ± 1% 6.31GB/s ± 1% +1.80% (p=0.008 n=5+5) RepeatLarge/131072/16-16 6.12GB/s ± 3% 6.25GB/s ± 3% ~ (p=0.095 n=5+5) RepeatLarge/131072/4097-16 5.95GB/s ± 1% 5.85GB/s ±10% ~ (p=1.000 n=5+5) RepeatLarge/262144/1-16 6.33GB/s ± 1% 6.56GB/s ± 0% +3.62% (p=0.016 n=5+4) RepeatLarge/262144/16-16 6.42GB/s ± 0% 6.65GB/s ± 1% +3.58% (p=0.016 n=4+5) RepeatLarge/262144/4097-16 6.31GB/s ± 1% 6.44GB/s ± 1% +1.94% (p=0.008 n=5+5) RepeatLarge/524288/1-16 6.23GB/s ± 1% 6.92GB/s ± 3% +11.02% (p=0.008 n=5+5) RepeatLarge/524288/16-16 6.24GB/s ± 1% 6.97GB/s ± 2% +11.77% (p=0.016 n=4+5) RepeatLarge/524288/4097-16 6.14GB/s ± 2% 6.73GB/s ± 3% +9.50% (p=0.008 n=5+5) RepeatLarge/1048576/1-16 5.23GB/s ± 1% 6.53GB/s ± 6% +24.85% (p=0.008 n=5+5) RepeatLarge/1048576/16-16 5.21GB/s ± 1% 6.56GB/s ± 4% +25.93% (p=0.008 n=5+5) RepeatLarge/1048576/4097-16 5.22GB/s ± 1% 6.26GB/s ± 2% +20.09% (p=0.008 n=5+5) RepeatLarge/2097152/1-16 3.95GB/s ± 1% 5.96GB/s ± 1% +51.01% (p=0.008 n=5+5) RepeatLarge/2097152/16-16 3.94GB/s ± 1% 5.98GB/s ± 2% +51.99% (p=0.008 n=5+5) RepeatLarge/2097152/4097-16 4.94GB/s ± 1% 5.71GB/s ± 2% +15.63% (p=0.008 n=5+5) RepeatLarge/4194304/1-16 3.10GB/s ± 1% 5.89GB/s ± 1% +89.90% (p=0.008 n=5+5) RepeatLarge/4194304/16-16 3.09GB/s ± 1% 5.86GB/s ± 1% +89.89% (p=0.008 n=5+5) RepeatLarge/4194304/4097-16 3.13GB/s ± 1% 5.89GB/s ± 1% +88.36% (p=0.008 n=5+5) RepeatLarge/8388608/1-16 3.06GB/s ± 1% 6.31GB/s ±16% +105.84% (p=0.008 n=5+5) RepeatLarge/8388608/16-16 3.08GB/s ± 1% 6.62GB/s ± 1% +114.66% (p=0.008 n=5+5) RepeatLarge/8388608/4097-16 3.13GB/s ± 2% 6.87GB/s ± 1% +119.62% (p=0.008 n=5+5) RepeatLarge/16777216/1-16 3.21GB/s ± 3% 5.88GB/s ± 1% +83.27% (p=0.008 n=5+5) RepeatLarge/16777216/16-16 3.23GB/s ± 2% 5.84GB/s ± 2% +80.49% (p=0.008 n=5+5) RepeatLarge/16777216/4097-16 3.30GB/s ± 6% 5.88GB/s ± 2% +78.18% (p=0.008 n=5+5) RepeatLarge/33554432/1-16 3.71GB/s ± 3% 5.91GB/s ± 2% +59.17% (p=0.008 n=5+5) RepeatLarge/33554432/16-16 3.67GB/s ± 3% 5.91GB/s ± 2% +61.13% (p=0.008 n=5+5) RepeatLarge/33554432/4097-16 3.71GB/s ± 1% 5.77GB/s ± 6% +55.51% (p=0.008 n=5+5) RepeatLarge/67108864/1-16 4.61GB/s ±11% 6.00GB/s ± 5% +30.15% (p=0.008 n=5+5) RepeatLarge/67108864/16-16 4.62GB/s ± 7% 6.11GB/s ± 2% +32.35% (p=0.008 n=5+5) RepeatLarge/67108864/4097-16 4.71GB/s ± 2% 6.24GB/s ± 2% +32.60% (p=0.008 n=5+5) RepeatLarge/134217728/1-16 4.53GB/s ± 8% 6.28GB/s ±11% +38.57% (p=0.008 n=5+5) RepeatLarge/134217728/16-16 4.78GB/s ± 3% 6.36GB/s ± 3% +33.16% (p=0.008 n=5+5) RepeatLarge/134217728/4097-16 4.73GB/s ± 6% 6.46GB/s ± 3% +36.63% (p=0.008 n=5+5) RepeatLarge/268435456/1-16 4.09GB/s ±25% 6.37GB/s ±19% +56.00% (p=0.008 n=5+5) RepeatLarge/268435456/16-16 4.50GB/s ± 4% 6.86GB/s ± 0% +52.49% (p=0.016 n=5+4) RepeatLarge/268435456/4097-16 4.73GB/s ± 5% 6.90GB/s ± 0% +45.94% (p=0.008 n=5+5) RepeatLarge/536870912/1-16 4.38GB/s ±36% 6.52GB/s ± 8% +48.68% (p=0.008 n=5+5) RepeatLarge/536870912/16-16 4.69GB/s ±12% 6.90GB/s ± 1% +46.97% (p=0.008 n=5+5) RepeatLarge/536870912/4097-16 4.87GB/s ± 8% 6.98GB/s ± 0% +43.36% (p=0.008 n=5+5) RepeatLarge/1073741824/1-16 3.87GB/s ±28% 6.96GB/s ± 1% +79.94% (p=0.016 n=5+4) RepeatLarge/1073741824/16-16 4.79GB/s ± 9% 6.93GB/s ± 0% +44.79% (p=0.008 n=5+5) RepeatLarge/1073741824/4097-16 4.65GB/s ± 8% 7.02GB/s ± 1% +51.02% (p=0.008 n=5+5) bytes: name old speed new speed delta RepeatLarge/256/1-16 1.93GB/s ± 1% 1.84GB/s ± 1% -4.81% (p=0.000 n=10+10) RepeatLarge/256/16-16 2.25GB/s ± 2% 2.15GB/s ± 1% -4.45% (p=0.000 n=9+8) RepeatLarge/512/1-16 2.71GB/s ± 1% 2.62GB/s ± 1% -3.27% (p=0.000 n=10+9) RepeatLarge/512/16-16 2.96GB/s ± 4% 2.91GB/s ± 1% ~ (p=0.243 n=9+10) RepeatLarge/1024/1-16 3.35GB/s ± 1% 3.27GB/s ± 1% -2.61% (p=0.000 n=9+10) RepeatLarge/1024/16-16 3.56GB/s ± 2% 3.52GB/s ± 1% -1.10% (p=0.010 n=10+9) RepeatLarge/2048/1-16 3.52GB/s ± 1% 3.45GB/s ± 1% -1.92% (p=0.000 n=10+10) RepeatLarge/2048/16-16 3.61GB/s ± 1% 3.58GB/s ± 0% -0.82% (p=0.008 n=9+8) RepeatLarge/4096/1-16 3.85GB/s ± 2% 3.80GB/s ± 2% ~ (p=0.165 n=10+10) RepeatLarge/4096/16-16 3.88GB/s ± 3% 3.84GB/s ± 4% ~ (p=0.393 n=10+10) RepeatLarge/8192/1-16 4.12GB/s ± 2% 4.04GB/s ± 1% -1.96% (p=0.000 n=10+10) RepeatLarge/8192/16-16 4.11GB/s ± 2% 4.09GB/s ± 1% ~ (p=0.278 n=9+10) RepeatLarge/8192/4097-16 4.38GB/s ± 1% 4.39GB/s ± 4% ~ (p=0.720 n=9+10) RepeatLarge/16384/1-16 5.06GB/s ± 2% 4.95GB/s ± 3% -2.29% (p=0.001 n=10+9) RepeatLarge/16384/16-16 5.11GB/s ± 3% 5.06GB/s ± 3% ~ (p=0.315 n=10+9) RepeatLarge/16384/4097-16 5.22GB/s ± 3% 5.26GB/s ± 3% ~ (p=0.211 n=9+10) RepeatLarge/32768/1-16 5.54GB/s ± 2% 5.50GB/s ± 3% ~ (p=0.353 n=10+10) RepeatLarge/32768/16-16 5.55GB/s ± 1% 5.60GB/s ± 1% +0.91% (p=0.035 n=10+9) RepeatLarge/32768/4097-16 4.88GB/s ± 2% 4.85GB/s ± 2% ~ (p=0.447 n=10+9) RepeatLarge/65536/1-16 5.86GB/s ± 1% 5.93GB/s ± 2% +1.18% (p=0.043 n=8+10) RepeatLarge/65536/16-16 5.83GB/s ± 2% 5.98GB/s ± 1% +2.67% (p=0.000 n=10+10) RepeatLarge/65536/4097-16 5.57GB/s ± 0% 5.56GB/s ± 3% ~ (p=0.696 n=8+10) RepeatLarge/131072/1-16 6.23GB/s ± 1% 6.38GB/s ± 2% +2.51% (p=0.000 n=9+10) RepeatLarge/131072/16-16 6.21GB/s ± 2% 6.37GB/s ± 1% +2.72% (p=0.000 n=9+10) RepeatLarge/131072/4097-16 6.04GB/s ± 1% 6.09GB/s ± 3% ~ (p=0.356 n=9+10) RepeatLarge/262144/1-16 6.47GB/s ± 1% 6.63GB/s ± 2% +2.57% (p=0.003 n=10+10) RepeatLarge/262144/16-16 6.45GB/s ± 2% 6.69GB/s ± 2% +3.65% (p=0.000 n=10+10) RepeatLarge/262144/4097-16 6.35GB/s ± 1% 6.51GB/s ± 2% +2.48% (p=0.000 n=9+10) RepeatLarge/524288/1-16 6.21GB/s ± 2% 6.95GB/s ± 1% +11.95% (p=0.000 n=10+10) RepeatLarge/524288/16-16 6.24GB/s ± 2% 6.93GB/s ± 2% +11.11% (p=0.000 n=10+10) RepeatLarge/524288/4097-16 6.18GB/s ± 2% 6.82GB/s ± 1% +10.39% (p=0.000 n=9+10) RepeatLarge/1048576/1-16 5.34GB/s ± 2% 6.41GB/s ± 2% +20.05% (p=0.000 n=10+10) RepeatLarge/1048576/16-16 5.33GB/s ± 1% 6.45GB/s ± 2% +20.84% (p=0.000 n=10+9) RepeatLarge/1048576/4097-16 5.28GB/s ± 1% 6.17GB/s ± 2% +16.75% (p=0.000 n=10+10) RepeatLarge/2097152/1-16 4.04GB/s ± 1% 6.21GB/s ± 1% +53.89% (p=0.000 n=9+8) RepeatLarge/2097152/16-16 4.02GB/s ± 1% 6.20GB/s ± 2% +54.37% (p=0.000 n=10+9) RepeatLarge/2097152/4097-16 4.94GB/s ± 1% 6.04GB/s ± 1% +22.36% (p=0.000 n=10+10) RepeatLarge/4194304/1-16 3.10GB/s ± 1% 5.74GB/s ± 0% +85.04% (p=0.000 n=10+9) RepeatLarge/4194304/16-16 3.10GB/s ± 2% 5.72GB/s ± 1% +84.26% (p=0.000 n=9+10) RepeatLarge/4194304/4097-16 3.03GB/s ± 4% 5.61GB/s ± 1% +85.06% (p=0.000 n=10+9) RepeatLarge/8388608/1-16 3.08GB/s ± 2% 6.25GB/s ± 1% +103.09% (p=0.000 n=9+9) RepeatLarge/8388608/16-16 3.07GB/s ± 2% 6.26GB/s ± 3% +104.07% (p=0.000 n=10+9) RepeatLarge/8388608/4097-16 3.08GB/s ± 2% 6.23GB/s ± 2% +102.09% (p=0.000 n=9+10) RepeatLarge/16777216/1-16 3.25GB/s ± 2% 5.78GB/s ± 3% +78.03% (p=0.000 n=9+9) RepeatLarge/16777216/16-16 3.25GB/s ± 1% 5.75GB/s ± 1% +77.21% (p=0.000 n=9+10) RepeatLarge/16777216/4097-16 3.29GB/s ± 3% 5.72GB/s ± 2% +73.74% (p=0.000 n=10+10) RepeatLarge/33554432/1-16 3.68GB/s ± 2% 5.90GB/s ± 1% +60.20% (p=0.000 n=10+10) RepeatLarge/33554432/16-16 3.69GB/s ± 3% 5.88GB/s ± 1% +59.54% (p=0.000 n=10+9) RepeatLarge/33554432/4097-16 3.74GB/s ± 1% 5.94GB/s ± 2% +58.68% (p=0.000 n=7+10) RepeatLarge/67108864/1-16 4.62GB/s ±12% 6.11GB/s ± 3% +32.23% (p=0.000 n=10+9) RepeatLarge/67108864/16-16 4.77GB/s ± 2% 6.09GB/s ± 2% +27.88% (p=0.000 n=9+9) RepeatLarge/67108864/4097-16 4.78GB/s ± 1% 6.19GB/s ± 1% +29.51% (p=0.000 n=9+10) RepeatLarge/134217728/1-16 4.60GB/s ±16% 6.52GB/s ± 9% +41.67% (p=0.000 n=10+10) RepeatLarge/134217728/16-16 4.80GB/s ± 4% 6.81GB/s ± 2% +41.82% (p=0.000 n=10+9) RepeatLarge/134217728/4097-16 4.79GB/s ± 4% 6.81GB/s ± 2% +42.31% (p=0.000 n=9+10) RepeatLarge/268435456/1-16 4.43GB/s ±25% 6.27GB/s ±14% +41.52% (p=0.000 n=10+10) RepeatLarge/268435456/16-16 4.75GB/s ± 4% 6.68GB/s ± 4% +40.50% (p=0.000 n=9+10) RepeatLarge/268435456/4097-16 4.75GB/s ± 3% 6.58GB/s ± 4% +38.68% (p=0.000 n=9+10) RepeatLarge/536870912/1-16 4.96GB/s ± 9% 6.39GB/s ±16% +28.90% (p=0.000 n=8+10) RepeatLarge/536870912/16-16 4.66GB/s ± 6% 6.57GB/s ± 7% +40.82% (p=0.000 n=10+9) RepeatLarge/536870912/4097-16 4.68GB/s ±11% 6.88GB/s ± 3% +47.01% (p=0.000 n=10+9) RepeatLarge/1073741824/1-16 4.39GB/s ±23% 6.57GB/s ± 5% +49.75% (p=0.000 n=10+8) RepeatLarge/1073741824/16-16 4.73GB/s ±13% 6.89GB/s ± 1% +45.68% (p=0.000 n=9+8) RepeatLarge/1073741824/4097-16 4.97GB/s ±15% 6.73GB/s ± 9% +35.45% (p=0.000 n=10+10) The results above come from a Intel i9-9980HK (256KB L2) with TurboBoost disabled. Change-Id: I79dd57da0429aee9020ffd7bc458a034b999b740 Reviewed-on: https://go-review.googlesource.com/c/go/+/419054 Reviewed-by: Ian Lance Taylor <iant@google.com> Auto-Submit: Ian Lance Taylor <iant@google.com> Run-TryBot: Ian Lance Taylor <iant@google.com> Reviewed-by: Dmitri Shuralyov <dmitshur@google.com> TryBot-Result: Gopher Robot <gobot@golang.org>
This commit adds an ASCII fast path to bytes/strings EqualFold that roughly doubles performance when all characters are ASCII. It also changes strings.EqualFold to use `for range` for the first string since this is ~10% faster than using utf8.DecodeRuneInString for both (see #31666). Performance (similar results on arm64 and amd64): name old time/op new time/op delta EqualFold/Tests-10 238ns ± 0% 172ns ± 1% -27.91% (p=0.000 n=10+10) EqualFold/ASCII-10 20.5ns ± 0% 9.7ns ± 0% -52.73% (p=0.000 n=10+10) EqualFold/UnicodePrefix-10 86.5ns ± 0% 77.6ns ± 0% -10.37% (p=0.000 n=10+10) EqualFold/UnicodeSuffix-10 86.8ns ± 2% 71.3ns ± 0% -17.88% (p=0.000 n=10+8) Change-Id: I058f3f97a08dc04d65af895674d85420f920abe1 Reviewed-on: https://go-review.googlesource.com/c/go/+/425459 Reviewed-by: Ian Lance Taylor <iant@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Auto-Submit: Ian Lance Taylor <iant@google.com> Run-TryBot: Ian Lance Taylor <iant@google.com> Reviewed-by: Cherry Mui <cherryyz@google.com>