JAX: Java performance myths # This talk was one of the famous talks on Java performance myths by Arno Haase. His main point - supported with dozens of illustrative examples was for software developers to stop trusting in word of mouth, cargo cult like myths that are abundant among engineers. Again the goal should be to write readable code above all - for one the Java compiler and JIT are great at optimising. ...
JAX: Does parallel equal performant? # In general there is a tendency to set parallel implementations to being equal to performant implementations. Except in the really naive case there is always going to be some overhead due to scheduling work, managing memory sharing and network communication overhead. Essentially that knowledge is reflected in Amdahl’s law (the amount of serial work limits the benefit from running parts of your implementation in parallel, http://en. ...
JAX: Pigs, snakes and deaths by 1k cuts # In his talk on performance problems Rainer Schuppe gave a great introduction to which kinds of performance problems can be observed in production and how to best root-cause them. Simply put performance issues usually arise due to a difference in either data volumn, concurrency levels or resource usage between the dev, qa and production environments. The tooling to uncover and explain them is pretty well known: ...
JAX: Java HPC by Norman Maurer # For slides see also: Speakerdeck: High performance networking on the JVM Norman started his talk clarifying what he means by high scale: Anything above 1000 concurrent connections in his talk are considered high scale, anything below 100 concurrent connections is fine to be handled with threads and blocking IO. Before tuning anything, make sure to measure if you have any problem at ...
JAX: Hadoop overview by Bernd Fondermann # After breakfast was over the first day started with a talk by Bernd on the Hadoop ecosystem. He did a good job selecting the most important and interesting projects related to storing data in HDFS and processing it with Map Reduce. After the usual "what is Hadoop", "what does the general architecture look like", "what will change with YARN" Bernd gave a nice overview of which ...
BigDataCon # Together with Uwe Schindler I had published a series of articles on Apache Lucene at Software and Support Media's Java Mag several years ago. Earlier this year S&S kindly invited my to their BigDataCon - co-located with JAX to give a talk of my choosing that at least touches upon Lucene. Thinking back and forth about what topic to cover what came to my mind was to ...
Hadoop Summit Amsterdam # About a month ago I attended the first European Hadoop Summit, organised by Hortonworks in Amsterdam. The two day conference brought together both vendors and users of Apache Hadoop for talks, exhibition and after conference beer drinking. Russel Jurney kindly asked me to chair the Hadoop applied track during Apache Con EU. As a result I had a good excuse to attend the event. Overall ...
ApacheConNA: Misc # In his talk on Spdy Mathew Steele explained how he implemented the spdy protocol as an Apache httpd module - working around most of the safety measures and design decisions in the current httpd version. Essentially to get httpd to support the protocol all you need now is mod_spdy plus a modified version of mod_ssl. The keynote on the last day was given by the Puppet founder. ...
ApacheConNA: Hadoop metrics # Have you ever measured the general behaviour of your Hadoop jobs? Have you sized your cluster accordingly? Do you know whether your work load really is IO bound or CPU bound? Legend has it noone expecpt Allen Wittenauer over at Linked.In, formerly Y! ever did this analysis for his clusters. Steve Watt gave a pitch for actually going out into your datacenter measuring what is going on there and adjusting the deployment accordingly: In small ...
ApacheConNA: Monitoring httpd and Tomcat # Monitoring - a task generally neglected - or over done - during development. But still vital enough to wake up people from well earned sleep at night when done wrong. Rainer Jung provided some valuable insights on how to monitor Apache httpd and Tomcat. Of course failure detection, alarms and notifications are all part of good monitoring. However so is avoidance of false positives and metric collection, ...