這篇文章主要介紹了關於php多進程執行任務的說明,有著一定的參考價值,現在分享給大家,有需要的朋友可以參考一下
#對指定數量的多個任務並發執行,並控制進程數
進程間相互獨立,不影響。
程式碼範例:
<?php $task = 0; //任务id $taskNum = 10; //任务总数 $processNumLimit = 2; //子进程总量限制 while(true){ //产生分支 $processid = pcntl_fork(); //创建子进程失败 if( $processid == -1 ){ echo "create process error!\n"; exit(1); } //主进程,获得子进程pid elseif($processid){ $task++; //下一个任务 $currentProcessid = posix_getpid(); //当前进程的Id $parentProcessid = posix_getppid(); // 父级进程的ID $phpProcessid = getmypid(); //当前php进程的id echo "task:",$task,"\tprocessid:",$processid,"\tcurrentProcessid:",$currentProcessid,"\tparentProcessid:",$parentProcessid,"\tphpProcessid:",$phpProcessid,"\n"; //控制进程数 if($task >= $processNumLimit) { echo "wait chl start!\n"; $exitid = pcntl_wait($status); //等待退出 echo "wait chl end!extid:",$exitid,"\tstatus:",$status,"\n"; } //任务总量控制 if($task >= $taskNum) { echo "taskNum enough!\n"; break; } } //processid=0为新创建的进程 else{ //模拟不同任务的不同执行时长 $sleep = rand(1, 5); $currentProcessid = posix_getpid(); //当前进程的Id $parentProcessid = posix_getppid(); // 父级进程的ID $phpProcessid = getmypid(); //当前php进程的id echo "task:",$task,"\tprocessid:",$processid,"\tcurrentProcessid:",$currentProcessid,"\tparentProcessid:",$parentProcessid,"\tphpProcessid:",$phpProcessid,"\tsleep:",$sleep,"\tbegin!\n"; sleep($sleep); echo "task:",$task,"\tprocessid:",$processid,"\tcurrentProcessid:",$currentProcessid,"\tparentProcessid:",$parentProcessid,"\tphpProcessid:",$phpProcessid,"\tsleep:",$sleep,"\tend!\n"; exit(0); //子进程执行完后退出,防止进入循环创建子进程 } }
執行的結果:
task:1 processid:32225 currentProcessid:32224 parentProcessid:15053 phpProcessid:32224 task:0 processid:0 currentProcessid:32225 parentProcessid:32224 phpProcessid:32225 sleep:5 begin! task:2 processid:32226 currentProcessid:32224 parentProcessid:15053 phpProcessid:32224 wait chl start! task:1 processid:0 currentProcessid:32226 parentProcessid:32224 phpProcessid:32226 sleep:2 begin! task:1 processid:0 currentProcessid:32226 parentProcessid:32224 phpProcessid:32226 sleep:2 end! wait chl end!extid:32226 status:0 task:3 processid:32228 currentProcessid:32224 parentProcessid:15053 phpProcessid:32224 wait chl start! task:2 processid:0 currentProcessid:32228 parentProcessid:32224 phpProcessid:32228 sleep:1 begin! task:2 processid:0 currentProcessid:32228 parentProcessid:32224 phpProcessid:32228 sleep:1 end! wait chl end!extid:32228 status:0 task:4 processid:32229 currentProcessid:32224 parentProcessid:15053 phpProcessid:32224 wait chl start! task:3 processid:0 currentProcessid:32229 parentProcessid:32224 phpProcessid:32229 sleep:2 begin! task:0 processid:0 currentProcessid:32225 parentProcessid:32224 phpProcessid:32225 sleep:5 end! wait chl end!extid:32225 status:0 task:5 processid:32270 currentProcessid:32224 parentProcessid:15053 phpProcessid:32224 wait chl start! task:4 processid:0 currentProcessid:32270 parentProcessid:32224 phpProcessid:32270 sleep:1 begin! task:3 processid:0 currentProcessid:32229 parentProcessid:32224 phpProcessid:32229 sleep:2 end! wait chl end!extid:32229 status:0 task:6 processid:32271 currentProcessid:32224 parentProcessid:15053 phpProcessid:32224 wait chl start! task:5 processid:0 currentProcessid:32271 parentProcessid:32224 phpProcessid:32271 sleep:4 begin! task:4 processid:0 currentProcessid:32270 parentProcessid:32224 phpProcessid:32270 sleep:1 end! wait chl end!extid:32270 status:0 task:7 processid:32273 currentProcessid:32224 parentProcessid:15053 phpProcessid:32224 wait chl start! task:6 processid:0 currentProcessid:32273 parentProcessid:32224 phpProcessid:32273 sleep:1 begin! task:6 processid:0 currentProcessid:32273 parentProcessid:32224 phpProcessid:32273 sleep:1 end! wait chl end!extid:32273 status:0 task:8 processid:32274 currentProcessid:32224 parentProcessid:15053 phpProcessid:32224 wait chl start! task:7 processid:0 currentProcessid:32274 parentProcessid:32224 phpProcessid:32274 sleep:2 begin! task:5 processid:0 currentProcessid:32271 parentProcessid:32224 phpProcessid:32271 sleep:4 end! task:7 processid:0 currentProcessid:32274 parentProcessid:32224 phpProcessid:32274 sleep:2 end! wait chl end!extid:32274 status:0 task:9 processid:32277 currentProcessid:32224 parentProcessid:15053 phpProcessid:32224 wait chl start! wait chl end!extid:32271 status:0 task:8 processid:0 currentProcessid:32277 parentProcessid:32224 phpProcessid:32277 sleep:2 begin! task:10 processid:32278 currentProcessid:32224 parentProcessid:15053 phpProcessid:32224 wait chl start! task:9 processid:0 currentProcessid:32278 parentProcessid:32224 phpProcessid:32278 sleep:2 begin! task:8 processid:0 currentProcessid:32277 parentProcessid:32224 phpProcessid:32277 sleep:2 end! task:9 processid:0 currentProcessid:32278 parentProcessid:32224 phpProcessid:32278 sleep:2 end! wait chl end!extid:32277 status:0 taskNum enough
在pcntl_fork出建立子行程後,子程序執行功能代碼,父程序繼續遞增任務id,創建下一個任務進程;
#透過pcntl_wait等待有子程序執行完畢退出後,再新創建進程,實現總進程數的控制;
在主程序完成創建後,透過break退出循環。此時可能有子程序繼續執行。
在目前行程目前位置產生分支(子行程)。成功時,在父行程執行緒內傳回產生的子程序的PID,在子程序執行緒內回傳0。失敗時,在 父進程上下文傳回-1,不會建立子進程,並且會引發一個PHP錯誤。
等待或傳回fork的子程序狀態。 wait函數刮起目前程序的執行直到一個子程序退出或接收到一個訊號要求中斷目前程序或呼叫一個訊號處理函數。如果一個子程序在呼叫此函數時已經退出(俗稱殭屍進程),此函數立刻回傳。子進程使用的所有系統資源將 被釋放。
1.殭屍行程及孤兒行程的問題
部分殭屍行程被pcntl_wait取得狀態並釋放資源,未接管的行程在主行程退出後成為孤兒進程。孤兒進程被init進程收養,完成wait的狀態取得和資源釋放。
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