关于php的set_time_limit和进程结束的问题

今日写了个php程序，其大概下：

<?php
set_time_limit(0);
require "../lib/Redis.class.php";
require "../config.php";

//define("PUSH_URL","ssl://gateway.sandbox.push.apple.com:2195");
define("PUSH_URL","ssl://gateway.push.apple.com:2195");

$redis = new Redis();
$key = "push_queue";
while (1){
    $len = $redis->llen($key);
    //push的时间为早晨9点到晚上10点
    $hour = intval(date("H"));
    if($hour>=9 && $hour<=22 && $len>0){
	$data = $redis->rpop($key);
	if (empty($data)){
		sleep(5);
	}
	if (!empty($data["device_token"]) && !empty($data["content"])){
		push($data["device_token"], $data["content"],$data["ck"]);//echo ($data["device_token"]);
	}
    }else{
        sleep(5);
    }
}

function push($device_token,$content,$ck){
    $deviceToken = trim($device_token);
    $body = array("aps" => array("alert" => "$content", "badge" => 1, "sound" => "received5.caf"));
    $ctx = stream_context_create();
    stream_context_set_option($ctx, "ssl", "local_cert",$ck);
    $fp = stream_socket_client(PUSH_URL, $err, $errstr, 60, STREAM_CLIENT_CONNECT, $ctx);
    if (!$fp) {
            //print "Failed to connect $err $errstr";
            return array("e"=>$err, "ee"=>$errstr);
    }
    //print "Connection OK
";
    $payload = json_encode($body);
    $msg = chr(0) . pack("n",32) . pack("H*", $deviceToken) . pack("n",strlen($payload)) . $payload;
    //print "sending message :" . $payload . "
";
    fwrite($fp, $msg);
    fclose($fp);
}

其实一看就知道这个是个死循环，用来做daemon进程的。但是先在浏览器测测，然后问题就来了。

我以为set_time_limit只是控制php的脚本执行时间，不会影响浏览器中停止脚本执行。但是我太天真了，我发现我就算在浏览器中终止了php脚本执行，发现nginx下的php-cgi仍然没有结束，就算把浏览器关了，改php-cgi进程还在执行中。