PHP多进程处理并行任务

/** 
 * this is a demo for php fork and pipe usage. fork use 
 * to create child process and pipe is used to sychoroize 
 * the child process and its main process. 
 * @author bourneli 
 * @date: 2012-7-6 
 */  
   
define("PC", 10); // 进程个数  
define("TO", 4); // 超时  
define("TS", 4); // 事件跨度，用于模拟任务延时  
   
if (!function_exists('pcntl_fork')) {  
    die("pcntl_fork not existing");  
}  
   
// 创建管道  
$sPipePath = "my_pipe.".posix_getpid();  
if (!posix_mkfifo($sPipePath, 0666)) {  
    die("create pipe {$sPipePath} error");  
}  
   
// 模拟任务并发  
for ($i = 0; $i < PC; ++$i ) {  
    $nPID = pcntl_fork(); // 创建子进程  
    if ($nPID == 0) {  
        // 子进程过程  
        sleep(rand(1,TS)); // 模拟延时  
        $oW = fopen($sPipePath, 'w');  
        fwrite($oW, $i."\n"); // 当前任务处理完比，在管道中写入数据  
        fclose($oW);  
        exit(0); // 执行完后退出  
    }  
}  
   
// 父进程  
$oR = fopen($sPipePath, 'r');  
stream_set_blocking($oR, FALSE); // 将管道设置为非堵塞，用于适应超时机制  
$sData = ''; // 存放管道中的数据  
$nLine = 0;  
$nStart = time();  
while ($nLine < PC && (time() - $nStart) < TO) {  
    $sLine = fread($oR, 1024);  
    if (empty($sLine)) {  
        continue;     
    }     
       
    echo "current line: {$sLine}\n";  
    // 用于分析多少任务处理完毕，通过‘\n’标识  
    foreach(str_split($sLine) as $c) {  
        if ("\n" == $c) {  
            ++$nLine;  
        }  
    }  
    $sData .= $sLine;  
}  
echo "Final line count:$nLine\n";  
fclose($oR);  
unlink($sPipePath); // 删除管道，已经没有作用了  
   
// 等待子进程执行完毕，避免僵尸进程  
$n = 0;  
while ($n < PC) {  
    $nStatus = -1;  
    $nPID = pcntl_wait($nStatus, WNOHANG);  
    if ($nPID > 0) {  
        echo "{$nPID} exit\n";  
        ++$n;  
    }  
}  
   
// 验证结果，主要查看结果中是否每个任务都完成了  
$arr2 = array();  
foreach(explode("\n", $sData) as $i) {// trim all  
    if (is_numeric(trim($i))) {  
        array_push($arr2, $i);    
    }  
}  
$arr2 = array_unique($arr2);  
if ( count($arr2) == PC) {    
    echo 'ok';   
} else {  
    echo  "error count " . count($arr2) . "\n";  
    var_dump($arr2);  
}