Abstract: Unjam CSS is a technique for removing render-blocking CSS from pages over which we have only partial control, such as CMS or portals. The problem: a portal generates HTML pages based on a template. Custom HTML can be inserted at specific place holders, but we can't modify the rest of the page HTML. The … Continue reading Unjam CSS
Category: performance
Tomcat starts slowly in docker container
Just a little reminder to self: when running Tomcat with Java 8 in an Ubuntu Docker container, Tomcat will take a very long time (minutes!) to start with even the simplest web application. The issue is actually documented (not entirely Docker-related). The solution is to modify JAVA_OPTS to use a different random device: JAVA_OPTS=-Djava.security.egd=file:/dev/urandom
Solving the 8 Queens puzzle with bit operations
The 8 queens puzzle is a classic (and quite fun to solve) toy problem: place eight queens on a chess board in such a way that all queens could fully move without being obstructed by any other queen. While without practical applications, it illustrates a number of aspects of designing algorithms and implementing programmes: - … Continue reading Solving the 8 Queens puzzle with bit operations
The "exe" process on slow Ubuntu bootchart
Ubuntu 11.10 does already a good job at starting faster, but if you've read one of my previous posts on Ubuntu startup time [1] then you know that there is always something to be tweaked for better or for worse. Part of the process is to defer services that are not needed immediately (i.e. printing) … Continue reading The "exe" process on slow Ubuntu bootchart
Speeding up Ubuntu 11.04 boot time
Just because I have nothing else to do on a lazy, rainy Sunday morning I thought it would be fun to see how much I can slash off the startup time for Ubuntu 11.04 64Bit on my HP Probook 4720s. The OS boots from a class 6 SD card (16 Mbyte/sec read) and 6 GB … Continue reading Speeding up Ubuntu 11.04 boot time
Varnish, session_linger and dropped connections
Recently I conducted a load test on my beloved low end Ubuntu 8.04 VPS. The setup consists of a mysql 5.1 DB, a Tomcat 6 webapp, openjdk 6 and Varnish 2.1.2. The load generator was issuing HTTP GET requests through a DSL connection which were supposed to create a decent load on Tomcat. To … Continue reading Varnish, session_linger and dropped connections
When IE does not load images
Recently the need for a custom photo gallery surfaced in one of my GWT pet projects. While such an endeavour seems endless from an artistic point of view, the mechanics behind it - at least for my humble needs - were rather simple:the gallery widget will be given a list of image IDsfor each ID … Continue reading When IE does not load images
