diff --git a/lib/TreeKill.js b/lib/TreeKill.js
index f3066d0e..6e429962 100644
--- a/lib/TreeKill.js
+++ b/lib/TreeKill.js
@@ -1,54 +1,31 @@
-/**!
- * treekill - index.js
- *
- * Copyright(c) fengmk2 and other contributors.
- * MIT Licensed
- *
- * Authors:
- *   fengmk2 <fengmk2@gmail.com> (http://fengmk2.github.com)
- *
- * Github:
- *   https://github.com/node-modules/treekill
- */
-
 /**
- * Module dependencies.
+ *
+ * Reference: https://github.com/pkrumins/node-tree-kill
+ * Author   : pkrumins
+ *
+ * Update   : PM2 team
+ *
  */
 
-var childProcess = require('child_process');
-var spawn = childProcess.spawn;
-var exec = childProcess.exec;
-var isWindows = process.platform === 'win32';
-var isDarwin = process.platform === 'darwin';
+var exec = require('child_process').exec,
+    isWin = process.platform === 'win32',
+    downgradePs = false;
 
-module.exports = treekill;
-
-function treekill(pid, signal, callback) {
-  if (typeof signal === 'function') {
-    callback = signal;
-    signal = null;
-  }
-
-  if (isWindows) {
+module.exports = function(pid, signal){
+  if (isWin) {
     exec('taskkill /pid ' + pid + ' /T /F');
   } else {
-    var tree = {};
-    tree[pid] = [];
-    var pidsToProcess = {};
-    pidsToProcess[pid] = 1;
-    buildProcessTree(pid, tree, pidsToProcess, function () {
+    var tree = {}, pidsToProcess = {};
+    buildProcessTree(pid, tree, pidsToProcess, function(){
       killAll(tree, signal);
-      if (typeof callback === 'function') {
-        callback();
-      }
     });
   }
 }
 
-function killAll(tree, signal) {
+function killAll(tree, signal){
   var killed = {};
-  Object.keys(tree).forEach(function (pid) {
-    tree[pid].forEach(function (pidpid) {
+  Object.keys(tree).forEach(function(pid){
+    tree[pid].forEach(function(pidpid){
       if (!killed[pidpid]) {
         killPid(pidpid, signal);
         killed[pidpid] = 1;
@@ -61,49 +38,73 @@ function killAll(tree, signal) {
   });
 }
 
-function killPid(pid, signal) {
+function killPid(pid, signal){
   try {
-    process.kill(parseInt(pid), signal);
-  } catch (err) {
-    if (err.code !== 'ESRCH') {
+    process.kill(pid, signal);
+  }
+  catch (err) {
+    if (err.code == 'EINVAL'){
+      throw new Error('The value of the sig argument is an invalid or unsupported signal number.');
+    }
+    if(err.code == 'EPERM'){
+      throw new Error('The process does not have permission to send the signal to any receiving process.');
+    }
+    if (err.code !== 'ESRCH'){
       throw err;
     }
   }
 }
 
-function buildProcessTree(ppid, tree, pidsToProcess, cb) {
-  var cmd = 'ps -e -o pid,ppid';
-  ppid = String(ppid);
-  exec(cmd, function (err, stdout, stderr) {
-    if (err) {
-      console.log(stderr);
-      throw err;
-    }
-    var lines = stdout.toString().split('\n');
-    lines = lines.map(function (line) {
-      return line.trim().split(/ +/).map(function (item) {
-        return item.trim();
-      });
-    });
+function buildProcessTree(ppid, tree, pidsToProcess, cb){
+  pidsToProcess[ppid] = 1;
+  tree[ppid] = [];
+
+  function isFinish(){
     delete pidsToProcess[ppid];
-
-    var pids = [];
-    for (var i = 0; i < lines.length; i++) {
-      var item = lines[i];
-      if (item[1] === ppid) {
-        pids.push(parseInt(item[0]));
-      }
-    }
-
-    if (pids.length === 0 && Object.keys(pidsToProcess).length === 0) {
+    if(Object.keys(pidsToProcess).length == 0){
       return cb();
     }
+  }
 
-    pids.forEach(function (pid) {
-      tree[ppid].push(pid);
-      tree[pid] = [];
-      pidsToProcess[pid] = 1;
-      buildProcessTree(pid, tree, pidsToProcess, cb);
+  var args = downgradePs ? '-eo pid,ppid | grep -w ' : '-o pid --no-headers --ppid ';
+  var ps = exec('ps ' + args + ppid, function(err, stdout, stderr){
+    if (err) {
+      // illegal option --, try to use basic `ps` instead of it.
+      if (/illegal/.test(err.message) && !downgradePs) {
+        downgradePs = true;
+        return buildProcessTree(ppid, tree, pidsToProcess, cb);
+      }
+
+      // Avoid pipe close error - dynamic self-closing process.
+      if(/Command failed/.test(err.message)) {
+        return isFinish();
+      }
+      throw err;
+    }
+
+    var pids = stdout.split('\n');
+
+    // remove parentPid if necessary.
+    downgradePs && pids.shift();
+
+    pids = pids.filter(function(pid){
+      return !!pid;
+    }).map(function(pid){
+      pid = pid.trim();
+      return parseInt(downgradePs ? pid.slice(0, pid.search(/\s/)) : pid, 10);
     });
+
+    if(pids.length > 0){
+      tree[ppid] = tree[ppid].concat(pids);
+      pids.forEach(function(pid){
+        if(!tree[pid]) {
+          buildProcessTree(pid, tree, pidsToProcess, cb);
+        }else{
+          delete pidsToProcess[pid];
+        }
+      });
+    }
+
+    isFinish();
   });
 }