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Date: Sun, 14 Jun 2015 21:35:35 -0600
Message-ID: <CAFMT4Nqn-C34LcFcrae10dpBDz6kwW21qtg=TQ_NM2i9sXSJhw@mail.gmail.com>
To: Yasuo Ohgaki <yohgaki@ohgaki.net>
Cc: "internals@lists.php.net" <internals@lists.php.net>
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Subject: Re: [PHP-DEV] Packed array is not fast?
From: levim@php.net (Levi Morrison)

On Thu, Jun 11, 2015 at 4:21 PM, Yasuo Ohgaki <yohgaki@ohgaki.net> wrote:
> 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

How are you testing hash vs packed? As far as what you posted I cannot
tell a difference =E2=80=93 it looks like you are running the same thing tw=
ice
(same binary and same input file).