usage - npm Package Compare versions

Comparing version 0.2.2 to 0.2.3

examples/test.js

@@ -1,13 +0,10 @@
-var usage = require('./');
+var usage = require('../');
+usage.setKeepHistory(true);
 
-checkUsage();
-setInterval(checkUsage, 1000);
+setInterval(function() {
 
-function checkUsage() {
+	usage.lookup(parseInt(process.argv[2]), function(err, stat) {
 
-	usage.lookup(process.pid, prt);
-}
-
-function prt () {
-	console.log(arguments);
-}
+		console.log(err, stat);
+	});
+}, 2000);

lib/usage.js

 var sysinfo = require('bindings')('sysinfo');
 var fs		= require('fs');
 
-console.log(sysinfo);
-
 var UPTIME_FILE = '/proc/uptime';
@@ -15,4 +13,9 @@ var STAT_FILE 	= '/proc/$pid/stat';
 
-function usageLookup(pid, callback) {
+var keepHistory = false;
+var historyCpuUsage = {};
 
+function usageLookup(pid, callback, useHistory) {
+
+	useHistory = useHistory || true;
+
 	if(!sysinfo.IS_SUPPORTED) {
@@ -39,6 +42,20 @@ return callback(new Error('NOT_SUPPORTED_ON_THIS_PLATFORM'));
 			var usageData = {
-				cpu: calculateCpuUsage(uptime, stat),
 				memory: calculateMemoryUsage(stat)
 			};
 
+			if(historyCpuUsage[pid] && useHistory) {
+				usageData['cpu'] = calculateCpuUsageFromHistory(uptime, stat, historyCpuUsage[pid]);
+			} else {
+				usageData['cpu'] = calculateCpuUsage(uptime, stat);
+			}
+
+			if(keepHistory) {
+				//save totalTime in history
+				historyCpuUsage[pid] = {
+					timestamp: Date.now(),
+					stat: stat,
+					uptime: uptime
+				};
+			}
+
 			callback(null, usageData);
@@ -57,2 +74,14 @@ }
 
+function calculateCpuUsageFromHistory(uptime, stat, lastUsage) {
+
+	var totalTime = (stat.stime + stat.utime) / sysinfo.HERTZ;
+	var lastTotalTime = (lastUsage.stat.stime + lastUsage.stat.utime) / sysinfo.HERTZ;
+
+	var usedTimeSinceLast = totalTime - lastTotalTime;
+	var timeSpent = uptime - lastUsage.uptime;
+
+	var pcpu = (usedTimeSinceLast / timeSpent) * 100;
+	return pcpu;
+}
+
 function calculateMemoryUsage(stat) {
@@ -101,4 +130,20 @@
 
+function setKeepHistory (value) {
+	
+	keepHistory = value;
+}
+
+function clearHistory (pid) {
+	
+	if(pid) {
+		historyCpuUsage[pid] = null;
+	} else {
+		historyCpuUsage = {};
+	}
+}
+
 exports.lookup = usageLookup;
+exports.setKeepHistory = setKeepHistory;
+exports.clearHistory = clearHistory;
 exports._getUptime= getUptime;
 exports._getStat = getStat;

package.json

 {
     "name": "usage",
-    "version": "0.2.2",
+    "version": "0.2.3",
     "description": "simple way to lookup linux process usage",
@@ -5,0 +5,0 @@ "keywords": [

README.md

@@ -29,2 +29,20 @@ [![Build Status](https://travis-ci.org/arunoda/node-usage.png?branch=master)](https://travis-ci.org/arunoda/node-usage)
 
+## Average CPU usage vs Current CPU usage
+
+By default CPU Percentage provided is a average from the starting time of the process. It does not correctly reflect the current CPU usage. (this is also a problem with linux `ps` utility)
+
+But If you call `usage.lookup()` continuously for a given pid, you can turn on **keepHistory** flag and you'll get the CPU usage since last time you track the usage. This reflects the current CPU usage. 
+
+see following example to enable keepHistory flag
+
+~~~js
+usage.setKeepHistory(true);
+~~~
+
+you can clear history cached too
+~~~js
+usage.clearHistory(pid); //clear history for the given pid
+usage.clearHistory(); //clean history for all pids
+~~~
+
 ## Motivation
@@ -31,0 +49,0 @@

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Found 1 instance in 1 package

Fixed alerts

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Improved metrics

Total package byte prevSize

8261

increased by23.76%

Lines of code

152

increased by21.6%

Number of lines in readme file

52

increased by52.94%

Worsened metrics

Number of package files

12

decreased by-7.69%

No dependency changes