Alex Zhitnitsky tkfx

Product Marketing @ OverOps

tkfx / tls.asm

Created July 21, 2016 14:37

	0x00007fd71508b1ec: mov 0x1b0(%r15),%r10 ;*invokestatic currentThread
	; - java.lang.ThreadLocal::get@0 (line 143)
	; - Opt::handleRequest@3 (line 70)
	0x00007fd71508b1f3: mov 0x50(%r10),%r11d ;*getfield threadLocals
	; - java.lang.ThreadLocal::getMap@1 (line 213)
	; - java.lang.ThreadLocal::get@6 (line 144)
	; - Opt::handleRequest@3 (line 70)

tkfx / tls.java

Last active July 24, 2016 09:58

	private static final ThreadLocal<Integer> counter = new ThreadLocal<Integer>();

	private static void handleRequest() {
	if (counter.get() == null) {
	counter.set(0);
	}

	counter.set(counter.get() + 1);

tkfx / calcLine2.Java

Last active July 21, 2016 15:45

	private static void calcLine(int a, int b, int from, int to) {
	Line l = new Line(a, b);
	for (int x = from; x <= to; x++) {
	int y = (l.a * x + l.b);
	System.err.println("(" + x + ", " + y + ")");
	}
	}

tkfx / calcLine1.java

Last active July 21, 2016 15:39

	private static void calcLine(int a, int b, int from, int to) {
	Line l = new Line(a, b);
	for (int x = from; x <= to; x++) {
	int y = l.getY(x);
	System.err.println("(" + x + ", " + y + ")");
	}
	}

	static class Line {
	public final int a;

tkfx / rolledLoop.java

Last active July 21, 2016 15:36

	private static double[] loopUnrolling(double[][] matrix1, double[] vector1) {
	double[] result = new double[vector1.length];

	for (int i = 0; i < matrix1.length; i++) {
	for (int j = 0; j < vector1.length; j++) {
	result[i] += matrix1[i][j] * vector1[j];
	}
	}

	return result;

tkfx / unrolledLoop.java

Last active July 21, 2016 15:37

	private static double[] loopUnrolling2(double[][] matrix1, double[] vector1) {
	double[] result = new double[vector1.length];

	for (int i = 0; i < matrix1.length; i++) {
	result[i] += matrix1[i][0] * vector1[0];
	result[i] += matrix1[i][1] * vector1[1];
	result[i] += matrix1[i][2] * vector1[2];
	// and maybe it will expand even further - e.g. 4 iterations, thus
	// adding code to fix the indexing
	// which we would waste more time doing correctly and efficiently

tkfx / unrolledLoop.asm

Last active July 21, 2016 15:37

	....
	0x00007fd715060743: vmovsd 0x10(%r8,%rcx,8),%xmm0 ;*daload
	; - Opt::loopUnrolling@26 (line 179)
	0x00007fd71506074a: vmovsd 0x10(%rbp),%xmm1 ;*daload
	; - Opt::loopUnrolling@36 (line 179)
	0x00007fd71506074f: vmulsd 0x10(%r12,%r9,8),%xmm1,%xmm1
	0x00007fd715060756: vaddsd %xmm0,%xmm1,%xmm0 ;*dadd
	; - Opt::loopUnrolling@38 (line 179)
	0x00007fd71506075a: vmovsd %xmm0,0x10(%r8,%rcx,8) ;*dastore
	; - Opt::loopUnrolling@39 (line 179)

tkfx / jge.asm

Last active July 21, 2016 15:36

tkfx / isOpt2.java

Last active July 21, 2016 15:14

	private static int isOpt(int x, int y) {
	int veryHardCalculation = 0;

	if (x < y) {
	// this would not require a jump
	veryHardCalculation = y * 1000 + x;
	return veryHardCalculation;
	} else {
	veryHardCalculation = x * 1000 + y;
	return veryHardCalculation;

tkfx / isOpt1.java

Last active July 21, 2016 15:14

	private static int isOpt(int x, int y) {
	int veryHardCalculation = 0;

	if (x >= y) {
	veryHardCalculation = x * 1000 + y;
	} else {
	veryHardCalculation = y * 1000 + x;
	}
	return veryHardCalculation;
	}