commit	7345fa54c17e979c4dc9d5c26c385d77ad614592	[log] [tgz]
author	Martin Möhrmann <martisch@uos.de>	Mon Mar 21 14:36:21 2016 +0100
committer	Rob Pike <r@golang.org>	Fri Apr 15 19:28:41 2016 +0000
tree	7ce252d0232ced4e1c1010daf1c151fbad8abe2e
parent	7f52b43954d75aa0c444d57b9d0eb7ff36eb3dd0 [diff]

fmt: optimize struct layout and intbuf size

Move boolean fields to the end of the pp struct for better packing.

Increase the fmt.intbuf size to leave no padding space unused
at the end of the fmt struct on 32 bit architectures.

The size of the pp struct on amd64 is decreased from 192 byte
to 184 byte and on 386 from 132 byte to 128 byte.

Simplify buffer size calculation in fmt_integer.

Consolidate test cases for intbuf overflow checks.

amd64 Haswell:

name                     old time/op  new time/op  delta
SprintfPadding-2          227ns ± 2%   227ns ± 1%    ~     (p=0.941 n=25+25)
SprintfEmpty-2           38.4ns ± 6%  35.8ns ±23%  -6.71%  (p=0.030 n=24+25)
SprintfString-2           100ns ± 0%   101ns ± 0%  +1.00%  (p=0.000 n=19+18)
SprintfTruncateString-2   142ns ± 1%   142ns ± 1%  +0.37%  (p=0.028 n=25+25)
SprintfQuoteString-2      397ns ± 0%   393ns ± 0%  -0.82%  (p=0.000 n=21+24)
SprintfInt-2              101ns ± 2%   102ns ± 4%    ~     (p=0.159 n=21+24)
SprintfIntInt-2           155ns ± 3%   155ns ± 3%    ~     (p=0.934 n=25+25)
SprintfPrefixedInt-2      252ns ± 2%   251ns ± 2%    ~     (p=0.198 n=25+25)
SprintfFloat-2            184ns ± 3%   179ns ± 2%  -3.07%  (p=0.000 n=24+25)
SprintfComplex-2          532ns ± 2%   535ns ± 2%  +0.64%  (p=0.046 n=25+24)
SprintfBoolean-2         90.5ns ± 3%  91.6ns ± 2%  +1.17%  (p=0.000 n=22+22)
SprintfHexString-2        164ns ± 2%   165ns ± 3%    ~     (p=0.066 n=25+25)
SprintfHexBytes-2         171ns ± 3%   170ns ± 3%    ~     (p=0.941 n=25+24)
SprintfBytes-2            320ns ± 1%   313ns ± 1%  -2.31%  (p=0.000 n=24+21)
SprintfStringer-2         347ns ± 2%   348ns ± 2%    ~     (p=0.426 n=24+24)
SprintfStructure-2        753ns ± 1%   742ns ± 1%  -1.49%  (p=0.000 n=24+25)
FprintInt-2               145ns ± 0%   144ns ± 0%  -0.69%  (p=0.000 n=24+23)
FprintfBytes-2            163ns ± 0%   163ns ± 0%  -0.27%  (p=0.000 n=25+25)
FprintIntNoAlloc-2        108ns ± 0%   105ns ± 0%  -2.78%  (p=0.000 n=25+2

386 Haswell:

name                     old time/op  new time/op  delta
SprintfPadding-2          426ns ± 2%   422ns ± 1%  -0.89%  (p=0.000 n=25+24)
SprintfEmpty-2           24.6ns ± 1%  24.5ns ± 0%  -0.39%  (p=0.000 n=22+15)
SprintfString-2          99.1ns ± 3%  95.6ns ± 0%  -3.52%  (p=0.000 n=25+24)
SprintfTruncateString-2   156ns ± 4%   153ns ± 1%  -1.65%  (p=0.000 n=24+23)
SprintfQuoteString-2      500ns ± 2%   493ns ± 1%  -1.49%  (p=0.000 n=25+24)
SprintfInt-2             92.6ns ± 9%  88.3ns ± 1%  -4.72%  (p=0.000 n=25+25)
SprintfIntInt-2           143ns ± 7%   137ns ± 2%  -4.01%  (p=0.000 n=23+25)
SprintfPrefixedInt-2      268ns ±19%   264ns ±16%    ~     (p=0.826 n=24+24)
SprintfFloat-2            242ns ± 4%   246ns ± 2%  +1.60%  (p=0.000 n=25+25)
SprintfComplex-2         1.04µs ± 3%  1.03µs ± 1%  -0.89%  (p=0.026 n=25+25)
SprintfBoolean-2         82.2ns ± 9%  80.7ns ± 2%    ~     (p=0.163 n=24+24)
SprintfHexString-2        240ns ± 5%   224ns ± 2%  -6.94%  (p=0.000 n=25+25)
SprintfHexBytes-2         245ns ± 3%   234ns ± 2%  -4.55%  (p=0.000 n=25+25)
SprintfBytes-2            432ns ±13%   419ns ± 2%    ~     (p=0.081 n=23+25)
SprintfStringer-2         356ns ± 4%   356ns ± 4%    ~     (p=0.988 n=25+25)
SprintfStructure-2        968ns ± 5%   948ns ± 2%  -2.11%  (p=0.000 n=25+25)
FprintInt-2               206ns ± 0%   201ns ± 0%  -2.43%  (p=0.000 n=25+21)
FprintfBytes-2            187ns ± 1%   187ns ± 1%    ~     (p=0.420 n=25+25)
FprintIntNoAlloc-2        173ns ± 0%   168ns ± 0%  -2.89%  (p=0.000 n=25+2

amd64 Ivy Bridge:

name                     old time/op  new time/op  delta
SprintfPadding-4          203ns ± 4%   210ns ± 8%  +3.27%  (p=0.000 n=23+25)
SprintfEmpty-4           24.4ns ± 2%  24.4ns ± 3%    ~     (p=0.487 n=24+25)
SprintfString-4          92.4ns ± 2%  93.1ns ± 3%    ~     (p=0.087 n=22+25)
SprintfTruncateString-4   137ns ± 3%   136ns ± 2%  -1.02%  (p=0.002 n=25+25)
SprintfQuoteString-4      378ns ± 1%   373ns ± 1%  -1.32%  (p=0.000 n=24+22)
SprintfInt-4             89.9ns ± 3%  90.3ns ± 4%    ~     (p=0.444 n=25+25)
SprintfIntInt-4           137ns ± 4%   138ns ± 3%    ~     (p=0.112 n=25+23)
SprintfPrefixedInt-4      155ns ±14%   154ns ±14%    ~     (p=0.791 n=25+25)
SprintfFloat-4            154ns ± 2%   154ns ± 3%    ~     (p=0.789 n=25+25)
SprintfComplex-4          396ns ± 2%   402ns ± 3%  +1.53%  (p=0.001 n=23+25)
SprintfBoolean-4         71.0ns ± 3%  71.2ns ± 2%    ~     (p=0.515 n=25+24)
SprintfHexString-4        156ns ± 3%   150ns ± 5%  -3.69%  (p=0.000 n=24+25)
SprintfHexBytes-4         154ns ± 3%   157ns ± 5%  +1.72%  (p=0.003 n=24+25)
SprintfBytes-4            297ns ± 4%   291ns ± 3%  -1.86%  (p=0.000 n=25+25)
SprintfStringer-4         275ns ± 3%   265ns ± 3%  -3.51%  (p=0.000 n=25+25)
SprintfStructure-4        878ns ± 2%   823ns ± 2%  -6.21%  (p=0.000 n=25+22)
FprintInt-4               145ns ± 1%   147ns ± 2%  +0.94%  (p=0.001 n=23+25)
FprintfBytes-4            166ns ± 1%   168ns ± 2%  +0.81%  (p=0.000 n=24+25)
FprintIntNoAlloc-4        113ns ± 2%   109ns ± 2%  -3.79%  (p=0.000 n=24+25)

386 Ivy Bridge:

name                     old time/op  new time/op  delta
SprintfPadding-4          353ns ± 4%   354ns ± 4%    ~     (p=0.769 n=25+24)
SprintfEmpty-4           21.9ns ± 6%  21.1ns ± 3%  -3.45%  (p=0.000 n=24+25)
SprintfString-4          94.7ns ± 1%  93.0ns ± 3%  -1.77%  (p=0.000 n=24+23)
SprintfTruncateString-4   150ns ± 2%   147ns ± 0%  -1.71%  (p=0.000 n=25+21)
SprintfQuoteString-4      472ns ± 1%   479ns ± 1%  +1.48%  (p=0.000 n=25+23)
SprintfInt-4             87.0ns ± 2%  85.3ns ± 2%  -1.95%  (p=0.000 n=25+25)
SprintfIntInt-4           137ns ± 2%   134ns ± 2%  -1.97%  (p=0.000 n=24+23)
SprintfPrefixedInt-4      166ns ± 8%   161ns ± 8%  -3.07%  (p=0.023 n=24+24)
SprintfFloat-4            226ns ± 1%   219ns ± 1%  -2.97%  (p=0.000 n=24+25)
SprintfComplex-4          867ns ± 1%   784ns ± 1%  -9.47%  (p=0.000 n=24+23)
SprintfBoolean-4         77.2ns ± 2%  76.0ns ± 2%  -1.63%  (p=0.000 n=25+25)
SprintfHexString-4        212ns ± 2%   214ns ± 2%  +0.96%  (p=0.000 n=25+25)
SprintfHexBytes-4         221ns ± 2%   218ns ± 1%  -1.42%  (p=0.000 n=25+24)
SprintfBytes-4            423ns ± 3%   417ns ± 1%  -1.49%  (p=0.000 n=25+24)
SprintfStringer-4         306ns ± 3%   298ns ± 3%  -2.57%  (p=0.000 n=24+25)
SprintfStructure-4       1.00µs ± 2%  0.98µs ± 2%  -1.34%  (p=0.000 n=24+24)
FprintInt-4               202ns ± 3%   197ns ± 2%  -2.04%  (p=0.000 n=25+25)
FprintfBytes-4            186ns ± 2%   184ns ± 2%  -0.88%  (p=0.000 n=24+25)
FprintIntNoAlloc-4        170ns ± 2%   166ns ± 2%  -2.26%  (p=0.000 n=24+25)

Change-Id: I46e62bf8b6afa90a24f75b40f1d354b2084b910b
Reviewed-on: https://go-review.googlesource.com/20984
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>

3 files changed

tree: 7ce252d0232ced4e1c1010daf1c151fbad8abe2e

README.md

The Go Programming Language

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For documentation about how to install and use Go, visit https://golang.org/ or load doc/install-source.html in your web browser.

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For example, if you extracted the tar file into $HOME/go, you might put the following in your .profile:

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