PHP/solution_1: Optimisation (PlummersSoftwareLLC#846)

Author: sqonk

PrimePHP/solution_1/Dockerfile

@@ -1,8 +1,11 @@
-FROM php:8.0-cli-alpine3.13
+FROM php:8.1.7-cli
 
-WORKDIR /opt/app
+# Use the default production configuration
+RUN mv "$PHP_INI_DIR/php.ini-production" "$PHP_INI_DIR/php.ini"
+# Enable opcache & JIT
+RUN printf "zend_extension=opcache.so\nopcache.enable=1\nopcache.enable_cli=1\nopcache.jit_buffer_size=100M\nopcache.jit=tracing\nmemory_limit=-1\n" >> "$PHP_INI_DIR/php.ini"
 
+WORKDIR /opt/app
 COPY *.php .
-COPY opcache.ini /usr/local/etc/php/conf.d/
 
 ENTRYPOINT [ "php", "PrimePHP.php" ]

PrimePHP/solution_1/PrimePHP.php

@@ -14,7 +14,7 @@
 
 class PrimeSieve
 {
-    private SplFixedArray $rawbits;
+    private string $rawbits;
 
     private int $sieveSize;
     private int $rawBitsSize;
@@ -42,11 +42,12 @@ public function runSieve()
         $sieveSize = $this->sieveSize;
         $q = sqrt($sieveSize);
 		$rawBitsSize = $this->rawBitsSize;
-        $rb = new SplFixedArray($rawBitsSize);
+        $rb = str_repeat('0', $rawBitsSize);
 
         while ($factor < $q) {
             for ($i = $factor; $i <= $sieveSize; $i += 2) {
-                if ($rb[$i * 0.5] === null) {
+                $rbi = (int)($i * 0.5);
+                if ($rb[$rbi] == '0') {
                     $factor = $i;
                     break;
                 }
@@ -55,7 +56,7 @@ public function runSieve()
             $ft2 = $factor;
             $start = (int)($factor * $factor * 0.5);
             for ($i = $start; $i < $rawBitsSize; $i += $ft2) {
-                $rb[$i] = 1;
+                $rb[$i] = '1';
             }
 
             $factor += 2;
@@ -66,7 +67,7 @@ public function runSieve()
     public function printResults(): void
     {
         for ($i = 1; $i < $this->sieveSize; $i++) {
-            if ($i % 2 && $this->rawbits[$i * 0.5] === null) {
+            if ($i % 2 && $this->rawbits[(int)($i * 0.5)] == '0') {
                 echo $i . ", ";
             }
         }
@@ -75,9 +76,9 @@ public function printResults(): void
     public function getRawbitCount(): int
     {
         $sum = 0;
-        $sz = $this->rawbits->getSize();
+        $sz = strlen($this->rawbits);
         for ($i = 0; $i < $sz; $i++){
-            if ($this->rawbits[$i] === null){
+            if ($this->rawbits[$i] == '0'){
                 $sum++;
             }
         }
@@ -120,7 +121,7 @@ public function getRawbitCount(): int
 
 // Following 2 lines added by rbergen to conform to drag race output format
 echo "\n\n";
-printf("DennisdeBest;%d;%f;1;algorithm=base,faithful=yes\n", $passes, ((float)$tD) / 1000);
+printf("DennisdeBest;%d;%f;1;algorithm=base,faithful=yes,bits=8\n", $passes, ((float)$tD) / 1000);
 
 function getTimeDiffInMs(float $tStart): float
 {

PrimePHP/solution_1/README.md

@@ -6,7 +6,10 @@ Leaned the loop logic.
 Uses factor * factor.
 Enabled JIT, small improvement in docker, native it gives me about 30% boost.
 
+Optimisations by sqonk:
+Changing SPLFixedArray to a simple string yields a nearly 2x performance increase.
+
 ![Algorithm](https://img.shields.io/badge/Algorithm-base-green)
 ![Faithfulness](https://img.shields.io/badge/Faithful-yes-green)
 ![Parallelism](https://img.shields.io/badge/Parallel-no-green)
-![Bit count](https://img.shields.io/badge/Bits-unknown-yellowgreen)
+![Bit count](https://img.shields.io/badge/Bits-8-yellowgreen)