float[][].
* Elements of the matrix A are initiated with random numbers,
* so that optimizing compiler could not eliminate any essential portion
* of calculations.
* *
That product A.A is calculated twice: in * a single thread, and in N separate threads, where NxN * is the size of square matrix A. When executing in N threads, * each thread calculate distinct row of the resulting matrix. The test checks * if the resulting product A.A is the same when * calculated in single thread and in N threads. *
*
By the way, the test checks JVM performance. The test is treated failed * due to poor performance, if single-thread calculation is essentially * slower than N-threads calculation (surely, the number of CPUs * installed on the platform executing the test is taken into account for * performance testing). Note, that HotSpot may fail to adjust itself for * better performance in single-thread calculation. *
*
See the bug-report:
*
* Command-line parameters are:
*
* Here:
*
* 4242172 (P3/S5) 2.0: poor performance in matrix calculations
*/
public class numeric002 {
private static final Random RNG = Utils.getRandomInstance();
/**
* When testing performance, single thread calculation is allowed to
* be 10% slower than multi-threads calculation (TOLERANCE
* is assigned to 10 now).
*/
public static final double TOLERANCE = 100; // 10;
/**
* Re-assign this value to true for better
* diagnostics.
*/
private static boolean verbose = false;
private static PrintStream out = null;
/**
* Print error-message to the out.
*/
private static void complain(Object x) {
out.println("# " + x);
}
private static void print(Object x) {
if (verbose)
out.print(x);
}
private static void println(Object x) {
print(x + "\n");
}
/**
* Re-invoke run(args,out) in order to simulate
* JCK-like test interface.
*/
public static void main(String args[]) {
int exitCode = run(args, System.out);
System.exit(exitCode + 95);
// JCK-like exit status
}
/**
* Parse command-line parameters stored in args[] and run
* the test.
*
* java numeric002 [-verbose] [-performance] [-CPU:number]
* matrixSize [threads]
*
-verbose -
* keyword, which alows to print execution trace
*
-performance -
* keyword, which alows performance testing
*
number -
* number of CPU installed on the computer just executing the test
*
matrixSize -
* number of rows (and columns) in square matrix to be tested
*
threads -
* for multi-thread calculation
* (default: matrixSize)
*
* @param args strings array containing command-line parameters
* @param out the test log, usually System.out
*/
public static int run(String args[], PrintStream out) {
numeric002.out = out;
boolean testPerformance = false;
int numberOfCPU = 1;
int argsShift = 0;
for (; argsShift < args.length; argsShift++) {
String argument = args[argsShift];
if (!argument.startsWith("-"))
break;
if (argument.equals("-performance")) {
testPerformance = true;
continue;
}
if (argument.equals("-verbose")) {
verbose = true;
continue;
}
if (argument.startsWith("-CPU:")) {
String value =
argument.substring("-CPU:".length(), argument.length());
numberOfCPU = Integer.parseInt(value);
if (numberOfCPU < 1) {
complain("Illegal number of CPU: " + argument);
return 2; // failure
}
continue;
}
complain("Cannot recognize argument: args[" + argsShift + "]: " + argument);
return 2; // failure
}
if ((args.length < argsShift + 1) || (args.length > argsShift + 2)) {
complain("Illegal argument(s). Execute:");
complain(
" java numeric002 [-verbose] [-performance] [-CPU:number] " +
"matrixSize [threads]");
return 2; // failure
}
int size = Integer.parseInt(args[argsShift]);
if ((size < 100) || (size > 10000)) {
complain("Matrix size should be 100 to 1000 lines & columns.");
return 2; // failure
}
int threads = size;
if (args.length >= argsShift + 2)
threads = Integer.parseInt(args[argsShift + 1]);
if ((threads < 1) || (threads > size)) {
complain("Threads number should be 1 to matrix size.");
return 2; // failure
}
if ((size % threads) != 0) {
complain("Threads number should evenly divide matrix size.");
return 2; // failure
}
print("Preparing A[" + size + "," + size + "]:");
SquareMatrix A = new SquareMatrix(size);
SquareMatrix A1 = new SquareMatrix(size);
SquareMatrix Am = new SquareMatrix(size);
println(" done.");
double singleThread = elapsedTime(out, A, A1, size, 1);
double multiThreads = elapsedTime(out, A, Am, size, threads);
if (!A1.isConsistent) {
complain("Failed to execute 1-thread calculation.");
return 2; // test FAILED
}
if (!Am.isConsistent) {
complain("Failed to execute " + threads + "-threads calculation.");
if (testPerformance) {
complain("I.e.: VM failed to execute " + threads + " threads,");
complain("and this looks like a performance bug.");
return 2; // test FAILED
} else {
complain("This looks strange, but this is not a bug.");
complain("The test is thought passed.");
return 0; // test PASSED
}
}
print("Checking accuracy:");
for (int line = 0; line < size; line++)
for (int column = 0; column < size; column++)
if (A1.value[line][column] != Am.value[line][column]) {
println("");
complain("Test failed:");
complain("Different results by single- and multi-threads:");
complain(" line=" + line + ", column=" + column);
complain("A1.value[line][column]=" + A1.value[line][column]);
complain("Am.value[line][column]=" + Am.value[line][column]);
return 2; // FAILED
}
println(" done.");
if (testPerformance) {
print("Checking performance: ");
double elapsed1 = singleThread;
double elapsedM = multiThreads * numberOfCPU;
if (elapsed1 > elapsedM * (1 + TOLERANCE / 100)) {
println("");
complain("Test failed:");
complain("Single-thread calculation is essentially slower:");
complain("Calculation time elapsed (seconds):");
complain(" single thread: " + singleThread);
complain(" multi-threads: " + multiThreads);
complain(" number of CPU: " + numberOfCPU);
complain(" tolerance: " + TOLERANCE + "%");
return 2; // FAILED
}
println("done.");
}
println("Test passed.");
return 0; // PASSED
}
private static double elapsedTime(PrintStream out,
SquareMatrix A, SquareMatrix AA, int size, int threads) {
print("Computing A*A with " + threads + " thread(s):");
long mark1 = System.currentTimeMillis();
AA.setSquareOf(A, threads);
long mark2 = System.currentTimeMillis();
println(" done.");
double sec = (mark2 - mark1) / 1000.0;
double perf = size * size * (size + size) / sec;
println("Elapsed time: " + sec + " seconds");
println("Performance: " + perf / 1e6 + " MFLOPS");
return sec;
}
/**
* This class computes A*A for square matrix A.
*/
private static class SquareMatrix {
volatile float value[][];
boolean isConsistent = false;
/**
* New square matrix with random elements.
*/
public SquareMatrix(int size) {
value = new float[size][size];
for (int line = 0; line < size; line++)
for (int column = 0; column < size; column++)
value[line][column] = (float) (RNG.nextDouble() * size);
isConsistent = true;
}
/**
* Update value[][] of this matrix.
*
* @param threads Split computation into the given number of threads.
*/
public void setSquareOf(SquareMatrix A, int threads) {
if (this.value.length != A.value.length)
throw new IllegalArgumentException(
"this.value.length != A.value.length");
int size = value.length;
if ((size % threads) != 0)
throw new IllegalArgumentException("size%threads != 0");
int bunch = size / threads;
Thread task[] = new Thread[threads];
for (int t = 0; t < threads; t++) {
int line0 = bunch * t;
MatrixComputer computer =
new MatrixComputer(value, A.value, line0, bunch);
task[t] = computer;
}
for (int t = 0; t < threads; t++)
task[t].start();
isConsistent = true;
for (int t = 0; t < threads; t++) {
if (task[t].isAlive())
try {
task[t].join();
} catch (InterruptedException exception) {
throw new RuntimeException(exception.toString());
}
if (!((MatrixComputer) (task[t])).threadExecuted) {
complain("Thread #" + t + " was not actually executed.");
isConsistent = false;
}
}
}
/**
* Thread to compute a bunch of lines of matrix square.
*/
private static class MatrixComputer extends Thread {
private float result[][];
private float source[][];
private int line0;
private int bunch;
/**
* Register a task for matrix multiplication.
*/
public MatrixComputer(
float result[][], float source[][], int line0, int bunch) {
this.result = result; // reference to resulting matrix value
this.source = source; // reference to matrix to be squared
this.line0 = line0; // compute lines from line0 to ...
this.bunch = bunch; // number of resulting lines to compute
}
/**
* Do execute the task just registered for this thread.
*/
public void run() {
int line1 = line0 + bunch;
int size = result.length;
for (int line = line0; line < line1; line++)
for (int column = 0; column < size; column++) {
float sum = 0;
for (int i = 0; i < size; i++)
sum += source[line][i] * source[i][column];
result[line][column] = sum;
}
threadExecuted = true;
}
/**
* Method run() sets this flag on is actually
* finishes to execute.
*/
boolean threadExecuted = false;
}
}
}