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ShiKaiWi 518ee55d78 expvar: improve Map.addKey for large number of keys 
The existing implementation has poor performance for inserting large
number of keys because it chooses to append the new key to the sorted
keys array and then sort the new array again (time complexity is
O(nlogn)).

The improvement tries to utilize the sorted keys array by searching the
index and doing an insertion if any (time complexity is O(logn)).

Benchmarked on 4-core machine with `go test -cpu 1,2,4,8 -count 5
-benchmem -bench=.`(the equal results are omitted):

name                          old time/op    new time/op    delta
MapAddDifferentRandom-8          408µs ±11%      69µs ± 3%  -82.95%  (p=0.008 n=5+5)
MapAddDifferentRandom-4          389µs ±19%      69µs ± 2%  -82.28%  (p=0.008 n=5+5)
MapAddDifferentRandom-2          365µs ± 4%      75µs ± 6%  -79.51%  (p=0.008 n=5+5)
MapSetDifferentRandom-8          365µs ± 4%      76µs ±40%  -79.07%  (p=0.008 n=5+5)
MapAddDifferentRandom            366µs ± 3%      78µs ± 6%  -78.66%  (p=0.008 n=5+5)
MapSetDifferentRandom            369µs ± 2%      81µs ±34%  -77.99%  (p=0.008 n=5+5)
MapSetDifferentRandom-2          378µs ±10%     100µs ±32%  -73.47%  (p=0.008 n=5+5)
MapSetDifferentRandom-4          352µs ± 4%     108µs ± 7%  -69.40%  (p=0.008 n=5+5)
IntAdd-2                        23.1ns ±21%    15.5ns ±23%  -32.79%  (p=0.032 n=5+5)
IntSet-2                        21.4ns ±14%    16.7ns ±17%  -22.00%  (p=0.016 n=5+5)
FloatAdd-8                      88.8ns ± 9%    70.8ns ±25%  -20.23%  (p=0.024 n=5+5)
FloatSet-2                      22.3ns ±15%    17.8ns ±14%  -20.14%  (p=0.008 n=5+5)
IntAdd-8                        21.7ns ± 3%    18.7ns ± 4%  -14.00%  (p=0.008 n=5+5)
MapAddDifferent-8               1.58µs ± 7%    1.42µs ± 6%  -10.06%  (p=0.016 n=5+5)
StringSet-2                     42.4ns ± 1%    43.7ns ± 5%   +3.07%  (p=0.048 n=4+5)
FloatSet                        8.27ns ± 2%    8.60ns ± 1%   +3.94%  (p=0.008 n=5+5)
FloatAdd                        12.5ns ± 2%    13.0ns ± 4%   +4.33%  (p=0.032 n=5+5)
MapSetString-4                  94.6ns ± 0%   101.7ns ± 4%   +7.55%  (p=0.016 n=4+5)
MapAddSameSteadyState-2         34.9ns ± 3%    37.7ns ± 5%   +8.14%  (p=0.008 n=5+5)
StringSet-4                     34.5ns ± 0%    37.6ns ± 9%   +9.02%  (p=0.016 n=4+5)
MapSetDifferent-8                377ns ± 3%     411ns ± 7%   +9.07%  (p=0.008 n=5+5)
MapAddSameSteadyState           39.1ns ± 2%    42.8ns ± 6%   +9.36%  (p=0.008 n=5+5)
MapAddDifferentSteadyState       172ns ± 4%     190ns ± 9%  +10.96%  (p=0.016 n=5+5)
MapSet                           143ns ± 4%     159ns ± 2%  +11.06%  (p=0.008 n=5+5)
MapSet-4                        96.9ns ± 5%   107.8ns ± 6%  +11.25%  (p=0.008 n=5+5)
MapSet-2                         102ns ± 6%     114ns ± 8%  +11.94%  (p=0.008 n=5+5)
IntSet                          8.18ns ± 1%   12.78ns ±13%  +56.31%  (p=0.008 n=5+5)

name                          old alloc/op   new alloc/op   delta
MapSetDifferentRandom-4         19.8kB ± 0%    16.6kB ± 0%  -16.21%  (p=0.008 n=5+5)
MapSetDifferentRandom           19.8kB ± 0%    16.6kB ± 0%  -16.21%  (p=0.008 n=5+5)
MapSetDifferentRandom-8         19.8kB ± 0%    16.6kB ± 0%  -16.20%  (p=0.008 n=5+5)
MapSetDifferentRandom-2         19.8kB ± 0%    16.6kB ± 0%  -16.20%  (p=0.008 n=5+5)
MapAddDifferentRandom           20.6kB ± 0%    17.4kB ± 0%  -15.57%  (p=0.008 n=5+5)
MapAddDifferentRandom-8         20.6kB ± 0%    17.4kB ± 0%  -15.57%  (p=0.008 n=5+5)
MapAddDifferentRandom-2         20.6kB ± 0%    17.4kB ± 0%  -15.56%  (p=0.008 n=5+5)
MapAddDifferentRandom-4         20.6kB ± 0%    17.4kB ± 0%  -15.56%  (p=0.008 n=5+5)
MapAddDifferent                 1.09kB ± 0%    0.96kB ± 0%  -11.76%  (p=0.008 n=5+5)
MapAddDifferent-2               1.09kB ± 0%    0.96kB ± 0%  -11.76%  (p=0.008 n=5+5)
MapAddDifferent-4               1.09kB ± 0%    0.96kB ± 0%  -11.76%  (p=0.008 n=5+5)
MapAddDifferent-8               1.09kB ± 0%    0.96kB ± 0%  -11.76%  (p=0.008 n=5+5)
MapAddSame                        480B ± 0%      448B ± 0%   -6.67%  (p=0.008 n=5+5)
MapAddSame-2                      480B ± 0%      448B ± 0%   -6.67%  (p=0.008 n=5+5)
MapAddSame-4                      480B ± 0%      448B ± 0%   -6.67%  (p=0.008 n=5+5)
MapAddSame-8                      480B ± 0%      448B ± 0%   -6.67%  (p=0.008 n=5+5)

name                          old allocs/op  new allocs/op  delta
MapSetDifferentRandom              423 ± 0%       323 ± 0%  -23.64%  (p=0.008 n=5+5)
MapSetDifferentRandom-2            423 ± 0%       323 ± 0%  -23.64%  (p=0.008 n=5+5)
MapSetDifferentRandom-4            423 ± 0%       323 ± 0%  -23.64%  (p=0.008 n=5+5)
MapSetDifferentRandom-8            423 ± 0%       323 ± 0%  -23.64%  (p=0.008 n=5+5)
MapAddDifferentRandom              523 ± 0%       423 ± 0%  -19.12%  (p=0.008 n=5+5)
MapAddDifferentRandom-2            523 ± 0%       423 ± 0%  -19.12%  (p=0.008 n=5+5)
MapAddDifferentRandom-4            523 ± 0%       423 ± 0%  -19.12%  (p=0.008 n=5+5)
MapAddDifferentRandom-8            523 ± 0%       423 ± 0%  -19.12%  (p=0.008 n=5+5)
MapAddDifferent                   31.0 ± 0%      27.0 ± 0%  -12.90%  (p=0.008 n=5+5)
MapAddDifferent-2                 31.0 ± 0%      27.0 ± 0%  -12.90%  (p=0.008 n=5+5)
MapAddDifferent-4                 31.0 ± 0%      27.0 ± 0%  -12.90%  (p=0.008 n=5+5)
MapAddDifferent-8                 31.0 ± 0%      27.0 ± 0%  -12.90%  (p=0.008 n=5+5)
MapAddSame                        11.0 ± 0%      10.0 ± 0%   -9.09%  (p=0.008 n=5+5)
MapAddSame-2                      11.0 ± 0%      10.0 ± 0%   -9.09%  (p=0.008 n=5+5)
MapAddSame-4                      11.0 ± 0%      10.0 ± 0%   -9.09%  (p=0.008 n=5+5)
MapAddSame-8                      11.0 ± 0%      10.0 ± 0%   -9.09%  (p=0.008 n=5+5)

Fixes #31414

Change-Id: I2dd655dec9dbbf8d7881a0f3f8edcb3d29199a48
GitHub-Last-Rev: a816fe3f62
GitHub-Pull-Request: golang/go#31418
Reviewed-on: https://go-review.googlesource.com/c/go/+/171718
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
 		2019-04-16 17:18:01 +00:00
.github .github: don't render author-facing text in ISSUE_TEMPLATE 2018-11-02 04:47:34 +00:00
api text/scanner: don't liberally consume (invalid) floats or underbars 2019-02-20 20:23:28 +00:00
doc doc: fix typo in go1.12 release notes 2019-04-16 14:47:58 +00:00
lib/time time: read 64-bit data if available 2019-02-26 23:10:35 +00:00
misc misc/cgo/testcshared: support testing on self-hosted android 2019-04-16 15:10:00 +00:00
src expvar: improve Map.addKey for large number of keys 2019-04-16 17:18:01 +00:00
test cmd/compile: update escape analysis tests for newescape 2019-04-16 16:20:39 +00:00
.gitattributes
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.gitignore .gitignore: ignore src/cmd/dist/dist 2017-10-28 21:55:49 +00:00
AUTHORS A+C: change email address for Elias Naur 2019-01-23 15:05:26 +00:00
CONTRIBUTING.md all: restore changes from faulty merge/revert 2018-02-12 20:13:59 +00:00
CONTRIBUTORS CONTRIBUTORS: second round of updates for Go 1.12 2019-01-30 18:01:19 +00:00
LICENSE doc: revert copyright date to 2009 2016-06-01 22:40:04 +00:00
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README.md README: linkify some paths 2018-06-06 18:07:01 +00:00
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