FileDocCategorySizeDatePackage
ParsePauses.javaAPI DocphoneME MR2 API (J2ME)6771Wed May 02 17:59:48 BST 2007None

ParsePauses

public class ParsePauses extends Object
This program parses the event.log generated by the VM and calculates the extend "pause" that can be noticed by the user. The algorithm moves a "sliding window" across the execution history of a program. If the amount of "stop-the-world" activities in a sliding window exceeds the threshold, we discover a pause. For example, if window_size is 30 and pause_thresh is 10, and the first 30 ms of the execution time contains 7 msec of GC and 5 msec of compilation for a total of 12 ms of stop-the-world activities, we declare that the first sliding window contains a pause.

Fields Summary
static int
window_size
The size of the sliding window, in milliseconds.
static int
pause_thresh
How much stop-the-world activities can happen in a sliding window before we declare that the sliding window contains a pause.
static boolean
verbose
Constructors Summary
Methods Summary
static booleanadd_pauses(java.util.Vector v, int startIdx, double begin)

        double end = begin + window_size;

        for (int pass = 0; pass < 2; pass++) {
            Node lastNode = null;
            double total_paused = 0.0;

            if (pass == 1 && verbose) {
                System.out.println("========================================");
                System.out.println("START" + begin);
            }
            for (int i=startIdx; i<v.size(); i++) {
                Node n = (Node)v.elementAt(i);

                if (pass == 1 && verbose) {
                    System.out.print("    " + n);
                }
                if (lastNode != null && lastNode.is_paused) {
                    double a = lastNode.msec;
                    double b = n.msec;
                    if (a < begin) {
                        a = begin;
                    }
                    if (b > end) {
                        b = end;
                    }
                    total_paused += (b - a);
                    if (pass == 1 && verbose) {
                        String s = new PrintfFormat("%7.3f").sprintf(b-a);
                        System.out.print(" += " + s);
                    }
                }
                if (pass == 1 && verbose) {
                    System.out.println();
                }
                lastNode = n;
                if (n.msec >= end) {
                    break;
                }
            }

            if (total_paused > pause_thresh) {
                if (pass == 1) {
                    String s = new PrintfFormat("%.3f").sprintf(total_paused);
                    if (verbose) {
                        System.out.println();
                    }
                    System.out.println("Pause at " + begin + " ms" + " = " + 
                                       s + " ms");
                    return true;
                }
            } else {
                return false;
            }
        }
        return true;
static intfindStartIdx(java.util.Vector v, int startIdx, double msec)

        boolean found = false;
        for (int i=startIdx; i<v.size(); i++) {
            Node n = (Node)v.elementAt(i);
            if (n.msec > msec) {
                if (!found) {
                    return startIdx;
                } else {
                    break;
                }
            }
            if (n.msec <= msec) {
                startIdx = i;
                found = true;
            }
        }
        if (!found) {
            return -1;
        } else {
            return startIdx;
        }
public static voidmain(java.lang.String[] args)

        try {
            int n = 0;
            if (args[0].equals("-v")) {
                n++;
                verbose = true;
            }
            window_size = Integer.parseInt(args[n+0]);
            pause_thresh = Integer.parseInt(args[n+1]);
        } catch (Throwable t) {;}

        FileInputStream in = new FileInputStream("event.log");
        BufferedReader reader = new BufferedReader(new InputStreamReader(in));
        String s;
        Vector v = new Vector();
        double last_msec = 0.0;
        int nestLevel = 0;
        while ((s = reader.readLine()) != null) {
            try {
                s = s.trim();
                String num = s.substring(0, s.indexOf(' "));
                double d = Double.parseDouble(num);
                Node n = new Node();
                n.msec = d;
                if (s.endsWith("END")) {
                    nestLevel --;
                } else {
                    nestLevel ++;
                }
                n.is_paused = (nestLevel) > 0;
                n.type = s.substring(s.lastIndexOf(' ")).intern();
                v.addElement(n);
                last_msec = d;
            } catch (Throwable t) {;}
        }

        int total_pauses = 0;
        int total_msecs = 0;
        int startIdx = 0;
        for (double msec = 0; msec < last_msec; msec += 1.0) {
            if ((startIdx = findStartIdx(v, startIdx, msec)) < 0) {
                break;
            }
            if (add_pauses(v, startIdx, msec)) {
                total_pauses ++;
            }
            total_msecs ++;
        }

        System.out.println("pauses = " + total_pauses + "/" +  total_msecs);