Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:25054
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Message-ID: <44CBA433.3030609@toggg.com>
Date: Sat, 29 Jul 2006 20:08:51 +0200
Reply-To:  bertrand@toggg.com
User-Agent: Mozilla Thunderbird 1.0.7-1.1.fc3 (X11/20050929)
MIME-Version: 1.0
To:  internals@lists.php.net
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Subject: does 16M give a counting overhead ?
From: bertrand@toggg.com (bertrand Gugger)

Bonsoir,
I sure bore the list , but I still miss something.
There was that thread about "memory_get_usage with new Memory Manager" 
where Ilia (et al.) evocated the overhead induced by the 
memory_get_usage() and family functions.
as , e.g. , in http://marc.theaimsgroup.com/?l=php-dev&m=115400370218834

So I just ask if and how it is possible to get 16M without the counting 
overhead.
--
toggg

> Ilia Alshanetsky wrote:
> 
>>
>> On 27-Jul-06, at 9:03 AM, bertrand Gugger wrote:
>>
>>>
>>> That may hear off topic , but how you enable something else than 8M  *without* getting this counting overhead ?
>>
>>
>>
>> Eh? When you set a limit what are you trying to do? From my  experience most of the time this setting is used by hosting providers  to restrict memory utilization of various PHP scripts to avoid out-of- memory situations and system abuse.
> 
> The most cases I saw were providers or production site wanting to grant *more* than 8M (typically 16M) to their customers / users.
> I dont call that a "restriction".
> You should know this 8M limit is reached very easily.
> e.g. lot of popular CMS wont work below this limit as soon as they have a litle contents.
> 
>> As such you'd want as accurate  measurement as possible including any overhead and what not, since it  is possible to use the overhead to exceed or in some cases even to  bypass the memory limit entirely.
> 
> You miss the point , they don't care about accuracy,
> they just don't want the default 8M but more.
> 
>>
>>> It looks to me that --enable-memory-limit mixes 2 independant roles :
>>> - setting the amount of available memory, and enabling eventually  local setting,
>>> - enabling the evaluation of the process consumption.
>>
>>
>>
>> That is correct. Memory limit by its nature requires PHP to count the  amount of memory consumed, since such tracking is performed it  enabled PHP to report internally via functions (or via Apache log)  about its memory utilization.
> 
> I have no idea how it works internally ...
> Are you meaning the default "hard-coded" 8M limit is magic and will not need to count the amount of memory consumed but any custom setting will ?
> -- 
> toggg