Posts on Daniel Mitterdorfer

part 1: Microbenchmarking in Java with JMH: An Introduction

In the previous post, I have introduced JMH with a Hello World benchmark. Now, let’s dig a bit deeper to find out more about the capabilities of JMH.

Cheap Read-Write Lock Explained

Tue, 29 Jul 2014 00:00:00 +0000

I have recently stumbled across a nice idiom called the cheap read-write lock. It is intended for very frequent concurrent reads of a field where synchronization would lead to too much contention. I think that the idiom is a bit odd and begs for an explanation.

Usage Scenario

For the sake of demonstration consider the following situation: Our system has a globally available calendar that holds the current day within the year. Every part of the system may read the current day. Once a day, a background thread will update it. Note that this scenario might not justify using the idiom in practice, but the example is sufficient for illustrating it.

Microbenchmarking in Java with JMH: Hello JMH

Tue, 17 Jun 2014 00:00:00 +0000

This is the fourth post in a series about microbenchmarking on the JVM with the Java Microbenchmarking Harness (JMH).

part 1: Microbenchmarking in Java with JMH: An Introduction

In the previous post I have shown different problems that we might miss when writing microbenchmarks from scratch. In this blog post I’ll introduce JMH and show how it helps us to avoid these problems.

Microbenchmarking in Java with JMH: Common Flaws of Handwritten Benchmarks

Tue, 20 May 2014 00:00:00 +0000

Image by Sarah; license: CC

This is the third post in a series about microbenchmarking on the JVM with the Java Microbenchmarking Harness (JMH).

part 1: Microbenchmarking in Java with JMH: An Introduction

In the previous post I have shown typical issues that have to be considered when executing microbenchmarks, such as the behavior of the JIT compiler or background system load. In this blog post we’ll discover different problems that you’ll encounter when writing microbenchmarks on the JVM.

Microbenchmarking in Java with JMH: Microbenchmarks and their environment

Mon, 14 Apr 2014 00:00:00 +0000

Image by Eduardo Diez Viñuela; license: CC

This is the second post in a series about microbenchmarking on the JVM with the Java Microbenchmarking Harness (JMH).

In the previous post I have introduced microbenchmarking. In this blog post we’ll discover different problems and precautions that should be taken when writing microbenchmarks on the JVM.

False Sharing

Fri, 28 Mar 2014 00:00:00 +0000

Normally, Java programmers are not too concerned about the hardware on which their beautiful software runs as long as provides loads of memory. Most of the time this is a good thing as software should solve a business problem rather than satisfying a machine. The JVM does a decent job hiding the underlying platform but as we know, abstractions are leaky. Sometimes we have to peek under hood, especially when we’re concerned about performance. One such topic is false sharing, were a very performance-critical component might not perform as well as we’d expect.

Microbenchmarking in Java with JMH: An Introduction

Tue, 18 Mar 2014 00:00:00 +0000

Image by Zach Dischner; license: CC

This is the first post in a series about microbenchmarking on the JVM with the Java Microbenchmarking Harness (JMH).