Hi Johannes,
thanks for the answer,
-----Message d'origine-----
De : Johannes Schlüter [mailto:johan...@schlueters.de]
Envoyé : vendredi 27 novembre 2015 14:42
À : 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.
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