php conference 2013 ja report
DESCRIPTION
PHPカンファレンス2013のセッション、「PHPコアから読み解く、定石の嘘ホント」を参考にまとめたスライドです。TRANSCRIPT
「PHPコアから読み解く 定石の嘘ホント」より
＠akirakoyasu
PHP CONFERENCE 2013 9/14 Sat. 大田区産業プラザPiO
Copyright © 2013 Akira Koyasu. Some rights reserved.
Theory
2
定石、定跡（じょうせき）とは、アブストラクトゲームにおける用語である。お互いが最善と考えられる手を行った場合の一連の手のこと。チェスでは、「セオリー」とも。石を用いる囲碁、オセロ、連珠などでは「定石」が、駒を用いる将棋、チェスなどでは「定跡」が用いられる。
- ja.wikipedia.org
photo#1
Copyright © 2013 Akira Koyasu. Some rights reserved. 3
Rule
２つのコードを見せます
どちらが速く動くか考えてください
考える時間は１０秒
相談しないで！
Copyright © 2013 Akira Koyasu. Some rights reserved.
Execution Time
4
$time1 = microtime(true);
// test code loop (100000 times)
$time2 = microtime(true);
printf("time: %f s\n", ($time2 - $time1));
Copyright © 2013 Akira Koyasu. Some rights reserved.
opcode
5
$ sudo pecl install channel://pecl.php.net/vld-0.12.0
$ php -dvld.active=1 -dvld.execute=0 test.php
Extension vld
Copyright © 2013 Akira Koyasu. Some rights reserved.
PHP runtime
6
.php.php.php Parser
Compiler
Virtual Machine
Copyright © 2013 Akira Koyasu. Some rights reserved.
PHP runtime
6
.php.php.php Parser
Compiler
Virtual Machine
AST
構文解析
Copyright © 2013 Akira Koyasu. Some rights reserved.
PHP runtime
6
.php.php.php Parser
Compiler
Virtual Machineopcode
AST
構文解析
コンパイル
Copyright © 2013 Akira Koyasu. Some rights reserved.
PHP runtime
6
.php.php.php Parser
Compiler
Virtual Machineopcode
AST
構文解析
コンパイル
実行
Copyright © 2013 Akira Koyasu. Some rights reserved. 7
Ready?
Copyright © 2013 Akira Koyasu. Some rights reserved.
Loop
8
A B
Copyright © 2013 Akira Koyasu. Some rights reserved.
Loop
8
$c = sizeof($arr);for ($i = 0; $i < $c; $i++) { $t = $arr[$i];}
foreach ($arr as $val) { $t = $val;}
A B
ただし、 とする$arr = range(0, 100);
Copyright © 2013 Akira Koyasu. Some rights reserved.
Loop
8
$c = sizeof($arr);for ($i = 0; $i < $c; $i++) { $t = $arr[$i];}
foreach ($arr as $val) { $t = $val;}
A B
ただし、 とする$arr = range(0, 100);
Copyright © 2013 Akira Koyasu. Some rights reserved.
foreach ($arr as $val) { $t = $val;}
$c = sizeof($arr);for ($i = 0; $i < $c; $i++) { $t = $arr[$i];}
FE_RESETFE_FETCH
DO_FCALL 'sizeof'IS_SMALLERPOST_INCFETCH_DIM_R
Answer
9
A B
Copyright © 2013 Akira Koyasu. Some rights reserved.
foreach ($arr as $val) { $t = $val;}
$c = sizeof($arr);for ($i = 0; $i < $c; $i++) { $t = $arr[$i];}
time: 0.683817 s
FE_RESETFE_FETCH
time: 1.043019 s
DO_FCALL 'sizeof'IS_SMALLERPOST_INCFETCH_DIM_R
Answer
9
A B
Copyright © 2013 Akira Koyasu. Some rights reserved.
foreach ($arr as $val) { $t = $val;}
$c = sizeof($arr);for ($i = 0; $i < $c; $i++) { $t = $arr[$i];}
time: 0.683817 s
FE_RESETFE_FETCH
time: 1.043019 s
DO_FCALL 'sizeof'IS_SMALLERPOST_INCFETCH_DIM_R
Answer
9
A B
Copyright © 2013 Akira Koyasu. Some rights reserved.
foreach ($arr as $val) { $t = $val;}
$c = sizeof($arr);for ($i = 0; $i < $c; $i++) { $t = $arr[$i];}
time: 0.683817 sFE_RESETFE_FETCHtime: 1.043019 s
DO_FCALL 'sizeof'IS_SMALLERPOST_INCFETCH_DIM_R
Answer
9
A B
Copyright © 2013 Akira Koyasu. Some rights reserved.
Elements
10
A B
Copyright © 2013 Akira Koyasu. Some rights reserved.
Elements
10
if (count($arr) > 0) { ;}
if (!empty($arr)) { ;}
$arr = array();ただし、 とする
A B
Copyright © 2013 Akira Koyasu. Some rights reserved.
Elements
10
if (count($arr) > 0) { ;}
if (!empty($arr)) { ;}
$arr = array();ただし、 とする
A B
Copyright © 2013 Akira Koyasu. Some rights reserved.
Answer
11
if (count($arr) > 0) { ;}
if (!empty($arr)) { ;}
A B
DO_FCALL 'count'IS_SMALLER
ISSET_ISEMPTY_VARBOOL_NOT
Copyright © 2013 Akira Koyasu. Some rights reserved.
Answer
11
if (count($arr) > 0) { ;}
if (!empty($arr)) { ;}
A B
time: 0.026228 s time: 0.008356 s
DO_FCALL 'count'IS_SMALLER
ISSET_ISEMPTY_VARBOOL_NOT
Copyright © 2013 Akira Koyasu. Some rights reserved.
Answer
11
if (count($arr) > 0) { ;}
if (!empty($arr)) { ;}
A B
time: 0.026228 s time: 0.008356 s
DO_FCALL 'count'IS_SMALLER
ISSET_ISEMPTY_VARBOOL_NOT
Copyright © 2013 Akira Koyasu. Some rights reserved.
Answer
11
if (count($arr) > 0) { ;}
if (!empty($arr)) { ;}
A B
time: 0.026228 s time: 0.008356 sDO_FCALL 'count'IS_SMALLER
ISSET_ISEMPTY_VARBOOL_NOT
Copyright © 2013 Akira Koyasu. Some rights reserved. 12
Points
測ってみる 調べてみる
考えてみる
Copyright © 2013 Akira Koyasu. Some rights reserved. 13
Any Questions?
Copyright © 2013 Akira Koyasu. Some rights reserved.
Notes
This work is licensed under the Creative Commons Attribution-NonCommercial 3.0 Unported License. To view a copy of this
license, visit http://creativecommons.org/licenses/by-nc/3.0/.
14
photo#1: http://www.flickr.com/photos/sbl/1617711/
Thank you very much, Feedback Welcome!
http://twitter.com/akirakoyasuhttp://fb.me/akirakoyasu
http://www.akirakoyasu.net