| commit | 691f5c34ad7b7d676644dd749bc4ddb5d20b90d0 | [log] [tgz] |
|---|---|---|
| author | erifan01 <eric.fang@arm.com> | Thu Jul 19 09:55:17 2018 +0000 |
| committer | Ian Lance Taylor <iant@golang.org> | Thu Sep 13 16:21:55 2018 +0000 |
| tree | c04bf83c53a3990a273652abcc34373a0300c5e9 | |
| parent | 77e503a3224ada21cc84ab9078980a7d4230492a [diff] |
strings, bytes: optimize function Index This change compares the first two characters instead of the first one, and if they match, the entire string is compared. Comparing the first two characters helps to filter out the case where the first character matches but the subsequent characters do not match, thereby improving the substring search speed in this case. Benchmarks with no effect or minimal impact (less than 5%) is not listed, the following are improved benchmarks: On arm64: strings: IndexPeriodic/IndexPeriodic16-8 172890.00ns +- 2% 124156.20ns +- 0% -28.19% (p=0.008 n=5+5) IndexPeriodic/IndexPeriodic32-8 78092.80ns +- 0% 65138.60ns +- 0% -16.59% (p=0.008 n=5+5) IndexPeriodic/IndexPeriodic64-8 42322.20ns +- 0% 34661.60ns +- 0% -18.10% (p=0.008 n=5+5) bytes: IndexPeriodic/IndexPeriodic16-8 183468.20ns +- 6% 123759.00ns +- 0% -32.54% (p=0.008 n=5+5) IndexPeriodic/IndexPeriodic32-8 84776.40ns +- 0% 63907.80ns +- 0% -24.62% (p=0.008 n=5+5) IndexPeriodic/IndexPeriodic64-8 45835.60ns +- 0% 34194.20ns +- 0% -25.40% (p=0.008 n=5+5) On amd64: strings: IndexPeriodic/IndexPeriodic8-16 219499.00ns +- 0% 178123.40ns +- 0% -18.85% (p=0.008 n=5+5) IndexPeriodic/IndexPeriodic16-16 109760.20ns +- 0% 88957.80ns +- 0% -18.95% (p=0.008 n=5+5) IndexPeriodic/IndexPeriodic32-16 54943.00ns +- 0% 44573.80ns +- 0% -18.87% (p=0.008 n=5+5) IndexPeriodic/IndexPeriodic64-16 29804.80ns +- 0% 24417.80ns +- 0% -18.07% (p=0.008 n=5+5) bytes: IndexPeriodic/IndexPeriodic8-16 226592.60ns +- 0% 181183.20ns +- 0% -20.04% (p=0.008 n=5+5) IndexPeriodic/IndexPeriodic16-16 111432.60ns +- 0% 90634.60ns +- 0% -18.66% (p=0.008 n=5+5) IndexPeriodic/IndexPeriodic32-16 55640.60ns +- 0% 45433.00ns +- 0% -18.35% (p=0.008 n=5+5) IndexPeriodic/IndexPeriodic64-16 30833.00ns +- 0% 24784.20ns +- 0% -19.62% (p=0.008 n=5+5) Change-Id: I2d9e7e138d29e960d20a203eb74dc2ec976a9d71 Reviewed-on: https://go-review.googlesource.com/131177 Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
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