May 2011 Guerrilla Classes: Light Bulb Moments

It's impossible to know what will constitute a light bulb moment for someone else. In the recent Guerrilla classes (GBoot and GCaP), we seemed to be having many more than our usual quota of such moments. So much so, that I decided to keep a list.

Applying PDQ in R to Load Testing

PDQ is a library of functions that helps you to express and solve performance questions about computer systems using the abstraction of queues. The queueing paradigm is a natural choice because, whether big (a web site) or small (a laptop), all computer systems can be represented as a network or circuit of buffers and a buffer is a type of queue.

Streeeeeeetch!

The October 2007 Linux Magazine (no. 10, issue 83, p. 62) is carrying the English version of my original German article about converting load averages to stretch factors. Unfortunately, there is no direct URL (Sun Oct 28, 2007: As Metapost commented below, it is now available for viewing) but the cute visual hook has a picture of a stretch limo ... stretched across two pages.

I wish I'd thought of that.

Leistungsdiagnostik - Load Averages and Stretch Factors

My latest article for the German Linux-Magazin has just appeared in the August edition under the title "Leistungsdiagnostik". The abstract reads:

Shellkommandos wie »uptime« werfen stets drei Zahlen als Load Average aus. Allerdings wissen nur wenige, wie sie zustande kommen und was genau sie bedeuten. Dieser Beitrag klärt darüber auf und stellt zugleich mit dem Stretchfaktor eine Erweiterung vor.

The main theme is about how to extend absolute load averages to relative stretch factor values.

How Long Should My Queue Be?

A simple question; there should be a simple answer, right? Guerrilla alumus Sudarsan Kannan asked me if a rule-of-thumb could be constructed for quantitatively assessing the load average on both dual-core and multicore platforms. He had seen various remarks, from time to time, alluding to optimal load averages.