Publications by Neil Gunther
Guerrilla Data Analysis Class – Seats Still Available
Most operating systems are capable of collecting hundreds of system and performance metrics every second. Even if you only record them once an hour, after a week you will have more than 50,000 samples; after a month you will be staring at almost a quarter of a million samples! But data are just data. How do you extract performance inf...
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How to Recover the Missing X(1) for the USL Scalability Model
When it comes to assessing application scalability, controlled measurements of the type that can be obtained with tools like Grinder or LoadRunner, are very useful because they provide a direct measurement of the throughput, X(N), as a function of the vuser/generator load, N. These data can be input easily into my universal scalabili...
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Review of R in NYT and GDAT
GDAT instructor, Jim Holtman, pointed me at this review of R in yesterday’s New York Times. It definitely puts SAS on the defensive.Update: Another piece in the tech section of NYT.If you want to know how to apply R to performance data, sign up for the Guerrilla Data Analysis Techniques class scheduled for August 2009 and learn from Jim person...
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PDQ-R Lives!
After some fiddling to get things linked correctly to the R binaries on my new Macbook, the first PDQ-R test model has run successfully! Here ‘tiz …This is an important step for PDQ development and is due entirely to the efforts of Phil Feller. Naturally, this capability will be included in the next PDQ release from SourceForge, w...
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Plotting PDQ Output with R
One the nice things about PDQ-R (coming in release 5.0) is the ability to plot PDQ output directly in R. Here’s a PDQ-R script, together with the corresponding graphical output, that I knocked up to show the effect on the throughput curve of adding more queueing delay stages (K), with everything else held constant. With just a sing...
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i-Screen, u-Screen, Vee All Screen for Which Screen?
When I first came to the USA, it quickly became apparent that there was no such thing as, ice cream. You had to specify what flavor, what combination of flavors, what kind of cone, what you wanted on top of it, and so on. This is all enshrined in the song I scream, You scream, We all scream for Ice Cream. Coming from England, I was no...
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Streaming Hadoop Data Into R Scripts
Along the lines of Mongo Measurement Requires Mongo Management, the HadoopStreaming package on CRAN provides utilities for applying R scripts to Hadoop streaming. Hadoop is used on Amazon’s EC2. Related To leave a comment for the author, please follow the link and comment on their blog: Taking the Pith Out of Performance. R-blog...
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Modern Microprocessor MIPS
The question of how modern microprocessors compare with mainframe processors of yore, arises from time to time. The vernacular rate metric that has persisted for a long time (long in the history of computers, that is) is MIPS. Whether you approve of MIPS as a valid performance metric or not is a different (philosophical) question. Si...
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PDQ 5.0 is on the Launch Pad
PDQ (Pretty Damn Quick) major release 5.0 is on the launch pad at Cape SourceForge. Because of a potential collision with the North Korean ICBM/satellite launch, we won’t be filling the main liquid-hydrogen tank until next week (we don’t want PDQ blamed for starting WW3). Of course, if you hijack the capsule ahead of time, we can...
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Barry3-Apdex Also Lives in R
As a by-product of my presentation on the Apdex Index at the NorCal CMG meeting, back in February, Guerrilla graduate, Stephen O’Connell, went off and did an implementation in R. You can read about it in this month’s CMG MeasureIT and download his R-script. Free access, but requires sign-up if you’re not already a member. Rela...
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