Blog Archives

Subjugation to the Sigmas

August 23, 2011
By
Subjugation to the Sigmas

No doubt you've heard about the tyranny of the 9s in reference to computer system availability. You're probably also familiar with the phrase six sigma, either in the context of manufacturing process quality control or the improvement of business processes. As we discovered in the recent Guerrilla Data Analysis Techniques class, the two concepts are related.

Read more »

GDAT 2011 in Review

August 13, 2011
By
GDAT 2011 in Review

As usual, the Guerrilla Data Analysis Techniques (GDAT) class was a total blast. Motivated students always guarantee that. It would really help our scheduling, however, if people didn't wait until the last nanosecond to register for the class. But give...

Read more »

Q-Q Plots for Multi-modal Performance Data

August 3, 2011
By
Q-Q Plots for Multi-modal Performance Data

I'm in the process of putting together some slides on how to apply Quantile-Quantile plots to performance data. Q-Q plots are a handy tool for visually inspecting how well your data matches a known probability distribution (prob dsn). If the match is g...

Read more »

A Winking Pink Elephant

June 27, 2011
By
A Winking Pink Elephant

The title of chapter 5 in my Guerrilla Capacity Planning book is, "Evaluating Scalability Parameters," and underneath it you'll see this quote:"With four parameters I can fit an elephant. With five I can make his trunk wiggle." —John von NeumannIn that vein, Guerrilla alumnus Stephen O'C. pointed me at a recent blog post and paper (PDF)...

Read more »

Go Guerrill-R on Your Data

May 31, 2011
By
Go Guerrill-R on Your Data

The Guerrilla Data Analysis Techniques training course (GDAT) will be held during the week of August 8-12 this year. As usual, the focus will be on applying R to your performance and capacity planning data, as well as how to use the PDQ-R modeling too...

Read more »

May 2011 Guerrilla Classes: Light Bulb Moments

May 23, 2011
By

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. The first was mine. Asa H. was having trouble...

Read more »

May 2011 Guerrilla Classes: Light Bulb Moments

May 23, 2011
By

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. The first was mine. Asa H. was having trouble...

Read more »

Applying PDQ in R to Load Testing

May 19, 2011
By
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...

Read more »

Applying PDQ in R to Load Testing

May 19, 2011
By
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...

Read more »

Reporting Standard Errors for USL Coefficients

November 13, 2010
By

In a recent Guerrilla CaP Group discussion, Baron S. wrote:....BS> Using gnuplot against the dataset I gave, I get BS>    sigma   0.0207163 +/- 0.001323 (6.385%) BS>    kappa   0.000861226 +/- 5.414e-05 (6.287%) The Gnuplot output includes the errors for each of the universal scalability law (USL) coefficients. A question about the magnitude of...

Read more »