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Commit Graph

11 Commits

Author SHA1 Message Date
Robert Griesemer
faa9d1eca9 strconv: use 64bit uint for decimal conversion if available
The existing code used ints for the (slow) decimal conversion and
assumed that they were 32bit wide.

This change uses uints and the appropriate width (32 or 64bit)
depending on platform.

The performance difference is in the noise for the usual (optimized)
case which does not use the slow path conversion:

benchmark                               old ns/op     new ns/op     delta
BenchmarkFormatFloatDecimal             298           299           +0.34%
BenchmarkFormatFloat                    388           392           +1.03%
BenchmarkFormatFloatExp                 365           364           -0.27%
BenchmarkFormatFloatNegExp              364           362           -0.55%
BenchmarkFormatFloatBig                 482           476           -1.24%
BenchmarkAppendFloatDecimal             100           102           +2.00%
BenchmarkAppendFloat                    199           201           +1.01%
BenchmarkAppendFloatExp                 174           175           +0.57%
BenchmarkAppendFloatNegExp              169           174           +2.96%
BenchmarkAppendFloatBig                 286           286           +0.00%
BenchmarkAppendFloat32Integer           99.9          102           +2.10%
BenchmarkAppendFloat32ExactFraction     161           164           +1.86%
BenchmarkAppendFloat32Point             199           201           +1.01%
BenchmarkAppendFloat32Exp               167           168           +0.60%
BenchmarkAppendFloat32NegExp            163           169           +3.68%
BenchmarkAppendFloat64Fixed1            137           134           -2.19%
BenchmarkAppendFloat64Fixed2            144           146           +1.39%
BenchmarkAppendFloat64Fixed3            138           140           +1.45%
BenchmarkAppendFloat64Fixed4            144           145           +0.69%

The performance difference is significant if the fast path conversion is
explicitly turned off (ftoa.go:101):

benchmark                               old ns/op     new ns/op     delta
BenchmarkFormatFloatDecimal             459           427           -6.97%
BenchmarkFormatFloat                    1560          1180          -24.36%
BenchmarkFormatFloatExp                 5501          3128          -43.14%
BenchmarkFormatFloatNegExp              24085         14360         -40.38%
BenchmarkFormatFloatBig                 1409          1081          -23.28%
BenchmarkAppendFloatDecimal             248           226           -8.87%
BenchmarkAppendFloat                    1315          982           -25.32%
BenchmarkAppendFloatExp                 5274          2869          -45.60%
BenchmarkAppendFloatNegExp              23905         14054         -41.21%
BenchmarkAppendFloatBig                 1194          860           -27.97%
BenchmarkAppendFloat32Integer           167           175           +4.79%
BenchmarkAppendFloat32ExactFraction     182           184           +1.10%
BenchmarkAppendFloat32Point             556           564           +1.44%
BenchmarkAppendFloat32Exp               1134          918           -19.05%
BenchmarkAppendFloat32NegExp            2679          1801          -32.77%
BenchmarkAppendFloat64Fixed1            274           238           -13.14%
BenchmarkAppendFloat64Fixed2            494           368           -25.51%
BenchmarkAppendFloat64Fixed3            1833          1008          -45.01%
BenchmarkAppendFloat64Fixed4            6133          3596          -41.37%

Change-Id: I829b8abcca882b1c10d8ae421d3249597c31f3c9
Reviewed-on: https://go-review.googlesource.com/3811
Reviewed-by: Russ Cox <rsc@golang.org>
2015-04-10 17:42:20 +00:00
Josh Bleecher Snyder
2adc4e8927 all: use "reports whether" in place of "returns true if(f)"
Comment changes only.

Change-Id: I56848814564c4aa0988b451df18bebdfc88d6d94
Reviewed-on: https://go-review.googlesource.com/7721
Reviewed-by: Rob Pike <r@golang.org>
2015-03-18 15:14:06 +00:00
Martin Möhrmann
d5b5d6702a strconv: simplify code for binary exponent float format
Use optimized formatBits function to format mantissa and exponent.
Add benchmark for binary exponent float format.

on darwin/386

benchmark                         old ns/op     new ns/op     delta
BenchmarkAppendFloatBinaryExp     520           122           -76.54%

on darwin/amd64

benchmark                         old ns/op     new ns/op     delta
BenchmarkAppendFloatBinaryExp     76.9          84.3          +9.62%

Change-Id: If543552f1960e1655bed3a4130914e5eaa3aac69
Reviewed-on: https://go-review.googlesource.com/5600
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-03-05 16:52:41 +00:00
Robert Griesemer
81a3f291f0 strconv: simplified logic resulting in faster float formatting
benchmark                               old ns/op     new ns/op     delta
BenchmarkFormatFloatDecimal             300           283           -5.67%
BenchmarkFormatFloat                    383           381           -0.52%
BenchmarkFormatFloatExp                 359           357           -0.56%
BenchmarkFormatFloatNegExp              357           358           +0.28%
BenchmarkFormatFloatBig                 468           430           -8.12%
BenchmarkAppendFloatDecimal             104           92.5          -11.06%
BenchmarkAppendFloat                    199           190           -4.52%
BenchmarkAppendFloatExp                 172           167           -2.91%
BenchmarkAppendFloatNegExp              172           169           -1.74%
BenchmarkAppendFloatBig                 280           235           -16.07%
BenchmarkAppendFloat32Integer           104           92.4          -11.15%
BenchmarkAppendFloat32ExactFraction     168           171           +1.79%
BenchmarkAppendFloat32Point             206           199           -3.40%
BenchmarkAppendFloat32Exp               167           167           +0.00%
BenchmarkAppendFloat32NegExp            167           166           -0.60%
BenchmarkAppendFloat64Fixed1            134           129           -3.73%
BenchmarkAppendFloat64Fixed2            144           136           -5.56%
BenchmarkAppendFloat64Fixed3            138           134           -2.90%
BenchmarkAppendFloat64Fixed4            145           138           -4.83%

Change-Id: Ia143840cb34cbd1cebd6b691dd0a45b7264b406c
Reviewed-on: https://go-review.googlesource.com/3920
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-02-11 17:45:19 +00:00
Robert Griesemer
9209d893c8 strconv: fix internal documentation (clarification, typos)
Change-Id: I7514e643a6a81ca715adbf6f8d19d3b2dd43fe6c
Reviewed-on: https://go-review.googlesource.com/3810
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-02-05 22:36:19 +00:00
Martin Möhrmann
06ed8f0df7 strconv: speed up atoi for common cases
Add compile time constants for bases 10 and 16 instead of computing the cutoff
value on every invocation of ParseUint by a division.

Reduce usage of slice operations.

amd64:
benchmark              old ns/op     new ns/op     delta
BenchmarkAtoi          44.6          36.0          -19.28%
BenchmarkAtoiNeg       44.2          38.9          -11.99%
BenchmarkAtoi64        72.5          56.7          -21.79%
BenchmarkAtoi64Neg     66.1          58.6          -11.35%

386:
benchmark              old ns/op     new ns/op     delta
BenchmarkAtoi          86.6          73.0          -15.70%
BenchmarkAtoiNeg       86.6          72.3          -16.51%
BenchmarkAtoi64        126           108           -14.29%
BenchmarkAtoi64Neg     126           108           -14.29%

Change-Id: I0a271132120d776c97bb4ed1099793c73e159893
Reviewed-on: https://go-review.googlesource.com/2460
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-01-08 20:58:26 +00:00
Martin Möhrmann
878fa886a6 strconv: add atoi tests for uncommon bases and syntax errors
Edge cases like base 2 and 36 conversions are now covered.
Many tests are mirrored from the itoa tests.

Added more test cases for syntax errors.

Change-Id: Iad8b2fb4854f898c2bfa18cdeb0cb4a758fcfc2e
Reviewed-on: https://go-review.googlesource.com/2463
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-01-08 16:51:47 +00:00
Martin Möhrmann
241583a432 strconv: optimize decimal to string conversion
Avoid the decimal lookup in digits array and compute the decimal character value directly.
Reduce calls to 64bit division on 32bit plattforms by splitting conversion into smaller blocks.
Convert value to uintptr type when it can be represented by uintptr.

on darwin/386

benchmark               old ns/op     new ns/op     delta
BenchmarkFormatInt      8352          7466          -10.61%
BenchmarkAppendInt      4281          3401          -20.56%
BenchmarkFormatUint     2785          2251          -19.17%
BenchmarkAppendUint     1770          1223          -30.90%

on darwin/amd64

benchmark               old ns/op     new ns/op     delta
BenchmarkFormatInt      5531          5492          -0.71%
BenchmarkAppendInt      2435          2295          -5.75%
BenchmarkFormatUint     1628          1569          -3.62%
BenchmarkAppendUint     726           750           +3.31%

Change-Id: Ifca281cbdd62ab7d7bd4b077a96da99eb12cf209
Reviewed-on: https://go-review.googlesource.com/2105
Reviewed-by: Robert Griesemer <gri@golang.org>
2014-12-30 23:28:02 +00:00
Martin Möhrmann
0668b595b6 strconv/itoa: add test to generate the longest output string possible by formatBits
The new test case produces the longest string representation possible and thereby uses
all of the 65 bytes in the buffer array used by the formatBits function.

Change-Id: I11320c4de56ced5ff098b7e37f1be08e456573e2
Reviewed-on: https://go-review.googlesource.com/2108
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2014-12-27 22:35:08 +00:00
Rob Pike
b6571a0713 strconv: fix documentation for CanBackquote.
Space is not a control character.

Fixes #8571.

LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/137380043
2014-09-09 11:45:36 -07:00
Russ Cox
c007ce824d build: move package sources from src/pkg to src
Preparation was in CL 134570043.
This CL contains only the effect of 'hg mv src/pkg/* src'.
For more about the move, see golang.org/s/go14nopkg.
2014-09-08 00:08:51 -04:00