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POPHP microtime strange behavior
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  1. POPHP microtime strange behavior
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    copied!<p>I was looking at execution time of some functions, but i have found that microtime is getting wrong, in one <code>microtime()</code> </p> <p><strong>implementation №1</strong> always first time is always getting more then second <code>microtime()</code> executing, when i testing one function and saw that one case is faster then another, but after place replace (<em>2nd function to 1st place</em>), it getting slower anyway, even if it was 3x faster...</p> <pre><code>function dotimes($times,$eval,$data=false) {for(;--$times;) eval($eval);} $start = microtime(true); dotimes(1000,'$i = $i?$times/2:1;'); printf(": executed : %f\n",microtime(true)-$start); $start = microtime(true); dotimes(1000,'$i = $i?$times/2:1;'); printf(": executed : %f\n",microtime(true)-$start); // 1st case is always slower... </code></pre> <p><strong>implementation №2</strong> iv made sometimes before <code>microtime()</code> as static data storage, but in that case the time of execute is always second time is slower then first (<em>oposite to implementation №1</em>)</p> <pre><code>function get_execution_time() { static $microtime_start = null; return $microtime_start === null ? $microtime_start = microtime(true) : microtime(true) - $microtime_start; } function dotimes($times,$eval,$data=false) {for(;--$times;) eval($eval);} get_execution_time(); dotimes(1000,'$i = $i?$times/2:1;'); printf(": executed : %f\n&lt;br&gt;",get_execution_time()); get_execution_time(); dotimes(1000,'$i = $i?$times/2:1;'); printf(": executed : %f\n&lt;br&gt;",get_execution_time()); //now 2nd case is faster.. </code></pre> <ul> <li>Can somebody tell me <strong>what is going up</strong>? Why these microtimes in one case 1st always slower, and throught static storage 2nd execute is slow down, <strong>WHY</strong>?</li> </ul> <p>ps if someone need tiny mt function here is my <strong>FIXED AND WORKING CORRECT</strong>:</p> <pre><code>function get_mt() {static $mt; return $mt ? microtime(true)-$mt.$mt=null : $mt=microtime(true);} </code></pre> <p>attached : </p> <pre><code>function get_mt() {static $mt; return $mt?microtime(true)-$mt:$mt=microtime(true);} function dotimes($times,$eval,$data=false) {for(;--$times;) eval($eval);} $start = microtime(true); get_mt(); dotimes(10000,'$i = $i?$times/2:1;'); printf(":clean executed : %f\n&lt;br&gt;",microtime(true)-$start); printf(":static executed : %f\n&lt;br&gt;",get_mt()); $start = microtime(true); get_mt(); dotimes(10000,'$i = $i?$times/2:1;'); printf(":clean executed : %f\n&lt;br&gt;",microtime(true)-$start); printf(":static executed : %f\n&lt;br&gt;",get_mt()); </code></pre>
 

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