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Date: Fri, 27 Nov 2015 15:27:41 +0100
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Subject: RE: [PHP-DEV] Proof of Concept : 3.5x and more Performance Boost for php7 using 4 cores
From: php-mailing-list@lool.fr ("Pascal KISSIAN")

Hi Johannes,
thanks for the answer,

-----Message d'origine-----
De : Johannes Schl=C3=BCter [mailto:johannes@schlueters.de]=20
Envoy=C3=A9 : vendredi 27 novembre 2015 14:42
=C3=80 : Pascal KISSIAN
Cc : internals@lists.php.net
Objet : Re: [PHP-DEV] Proof of Concept : 3.5x and more Performance Boost =
for php7 using 4 cores

>Your test runs a single PHP process. Mind that in a typical deployment =
on a server you have quite a few parallel PHP processes already =
competing for time on the CPU (when not >waiting for IO) a benchmark =
should reflect that.
	You can see  at =
http://poc.yakpro.com/?php7_performance_boost_parallel_computing ,
	in the " Faq: Is it usefull on a heavy traffic web site? " section, a =
graph that answers partially your question.

>For in_array I'm assuming that often either one or no match exist, thus =
in average the old algorithm has to process half the elements in =
average. With that form of parallelization it >will process C/(N -1) + =
C/2N elements where C is the count of elements and N the number of =
cores, so in total need more CPU. (might be wrong)
	In the new algorithm, each core processes C/2N elements in parallel, =
and when one core has found a result, the process is stopped for the =
other cores...
	so the average cpu need is C/2N  * N  so exactly the same C/2.

>So please run tests with a "typical" application (like wordpress or
>such) in a more typical environment.
	Do you know a real application that is executing only array_sum() or =
in_array() functions?
	If the time of those functions represent only 0.5% of global run time, =
we will just speed-up those 0.5%....

	I have not rewritten all php in parallel...
	I just did a "Proof of Concept", to be sure that it is possible to run =
some php functions in parallel, and this in less time.

	And I hope that many people will be interested to start thinking =
parallel in php, as the next speed improvements in hardware will be the =
multiplication of cores in a cpu.