Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:86601
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: pass (pb1.pair.com: domain gmail.com designates 209.85.160.195 as permitted sender)
MIME-Version: 1.0
Sender: yohgaki@gmail.com
Date: Fri, 12 Jun 2015 07:21:21 +0900
Message-ID: <CAGa2bXaWaAVQq8re-hH5juQ5o-Rhnf5wJoZCa+1aW2yPK3uBrA@mail.gmail.com>
To: "internals@lists.php.net" <internals@lists.php.net>
Content-Type: multipart/alternative; boundary=001a1146c7f2ab73fc0518456be6
Subject: Packed array is not fast?
From: yohgaki@ohgaki.net (Yasuo Ohgaki)

--001a1146c7f2ab73fc0518456be6
Content-Type: text/plain; charset=UTF-8

Hi all,

I've tried to see how packed array is faster with following code

http://3v4l.org/TQd6c

I confirmed when start index is non-zero, hash is used by
zend_hash_index_find().
I got following result. (with much larger number of elements/loops)

Fedora 22 + current master without --enable-debug
1st "Time" is total execution time.
2nd "Time" is the time spent by "for loop"

Hash
[yohgaki@dev php-src]$ ./php-bin ~/tmp/array_bench2.php
Time: 1.7903809547424
Time: 1.1529920101166
[yohgaki@dev php-src]$ ./php-bin ~/tmp/array_bench2.php
Time: 1.8049499988556
Time: 1.1719739437103

Packed
[yohgaki@dev php-src]$ ./php-bin ~/tmp/array_bench2.php
Time: 1.7407248020172
Time: 1.1594388484955
[yohgaki@dev php-src]$ ./php-bin ~/tmp/array_bench2.php
Time: 1.7248120307922
Time: 1.1530420780182

Packed array is not so fast, even if zend_hash.c seems much
faster with packed array.

Just FYI.

Regards,

P.S. Am I doing something wrong?
HHVM seems to have optimization margins for hash and loop.

--
Yasuo Ohgaki
yohgaki@ohgaki.net

--001a1146c7f2ab73fc0518456be6--