Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:41664
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: error (pb1.pair.com: domain pooteeweet.org from 88.198.8.16 cause and error)
Cc: Karoly Negyesi <karoly@negyesi.net>,
 internals@lists.php.net
Message-ID: <EC8C4CC0-4089-422B-9223-CCDD8A796341@pooteeweet.org>
To: shire <shire@tekrat.com>
In-Reply-To: <243C7392-C6A0-4EE8-8AAA-34964E78D453@tekrat.com>
Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes
Content-Transfer-Encoding: 7bit
Mime-Version: 1.0 (Apple Message framework v929.2)
Date: Tue, 4 Nov 2008 22:53:36 +0100
References: <7e270cea0810191211w2cb77075y5e0ad78c2f7306f7@mail.gmail.com> <243C7392-C6A0-4EE8-8AAA-34964E78D453@tekrat.com>
Subject: Re: [PHP-DEV] An optimization idea
From: mls@pooteeweet.org (Lukas Kahwe Smith)

Hello again,

once again top posting this this is fairly old ..
however for something that is sounding so promising I am wondering why  
this hasnt been picked up ..

regards,
Lukas

On 20.10.2008, at 22:09, shire wrote:

>
> On Oct 19, 2008, at 12:11 PM, Karoly Negyesi wrote:
>
>> Hi,
>>
>> I think zend_hash_compare could get a healthy speed boost in some
>> cases if first it would check whether the two variables passed to it
>> are actually the same (because of "reference counting"). Sorry, my C
>> skills are way too rusty to write the patch which is likely to be  
>> just
>> a few lines long.
>>
>
>
> A quick patch/test seems to agree with you, I'd be interested to  
> know if you/others  are able to apply this patch and see any real- 
> world savings with your web application.  The following was done  
> with a debug build of PHP so results are likely exaggerated.  I'm  
> also using non-recursive array with 256 byte strings below, results  
> with numeric values are less significant of course (approx a 25%  
> gain)...
>
> I'll also look into applying this to some other functions like  
> compare_function where it's likely to yield a larger savings in a  
> general application.
>
>
> patch against php-5.2 CVS head
> --------------------------
> iff --git a/Zend/zend_hash.c b/Zend/zend_hash.c
> index a1d7071..d11785f 100644
> --- a/Zend/zend_hash.c
> +++ b/Zend/zend_hash.c
> @@ -1327,16 +1327,14 @@ ZEND_API int zend_hash_compare(HashTable  
> *ht1, HashTable *ht2, compare_func_t co
>        IS_CONSISTENT(ht1);
>        IS_CONSISTENT(ht2);
>
> -       HASH_PROTECT_RECURSION(ht1);
> -       HASH_PROTECT_RECURSION(ht2);
> -
>        result = ht1->nNumOfElements - ht2->nNumOfElements;
> -       if (result!=0) {
> -               HASH_UNPROTECT_RECURSION(ht1);
> -               HASH_UNPROTECT_RECURSION(ht2);
> +       if (ht1 == ht2 || result!=0) {
>                return result;
>        }
>
> +       HASH_PROTECT_RECURSION(ht1);
> +       HASH_PROTECT_RECURSION(ht2);
> +
>        p1 = ht1->pListHead;
>        if (ordered) {
>                p2 = ht2->pListHead;
>
>
>
> simple test script
> -------------------------------
> <?php
>
> $arr1 = array();
> for ($i=0; $i < 10000; $i++) {
>  $arr1[$i] = str_repeat('x', 256);
> }
> $arr2 = array();
> for ($i=0; $i < 10000; $i++) {
>  $arr2[$i] = str_repeat('x', 256);
> }
> $arr3 = $arr1;
>
> $count = 0;
> $start = microtime(true);
> for ($i = 0; $i < 1000; $i++) {
>  if ($arr1 == $arr2) {
>    $count++;
>  }
> }
> $stop = microtime(true);
> echo "different array time: ".($stop-$start)."\n";
> echo "count: $count \n";
>
> $count = 0;
> $start = microtime(true);
> for ($i = 0; $i < 1000; $i++) {
>  if ($arr1 == $arr3) {
>    $count++;
>  }
> }
> $stop = microtime(true);
> echo "identical array time: ".($stop-$start)."\n";
> echo "count: $count \n";
> -------------------------------
>
> (un-patched php build)
> shire@shirebook:~/data/php/git/php$ ./sapi/cli/php.vanilla test.php
> different array time: 4.2019698619843
> count: 1000
> identical array time: 2.4957029819489
> count: 1000
>
> (patched build)
> shire@shirebook:~/data/php/git/php$ ./sapi/cli/php test.php
> different array time: 4.059928894043
> count: 1000
> identical array time: 0.00043511390686035
> count: 1000
>
>
> -shire
>
> -- 
> PHP Internals - PHP Runtime Development Mailing List
> To unsubscribe, visit: http://www.php.net/unsub.php
>

Lukas Kahwe Smith
mls@pooteeweet.org