Possibly pithy insights into computer performance analysis and capacity planning based on the Guerrilla series of books and training classes provided by Performance Dynamics Company .
How to Quantify Scalability: Synopsis of The Universal Scalability Law (USL) , has just been posted in PDF format for improved readability. I did this post haste so, reporting any typos, broken links, etc., is always appreciated.
Just updated my " Performance Ponderings " page. It covers my performance analysis papers published over the past 35 yrs. 😳 You may be thinking: Who cares about performance analysis cases that is that dated? Amazingly, performance analysis (done right) is often not technology-dependent, per se. The right abstraction can remain invariant into perpetuity. For example, my 2025 analysis of the GPT…
Functional equation question seen on Twitter : This is my general solution, computed in Mathematica: a functional programming language. Scroll through the PDF for details.
This talk will be presented at the APS Global Physics Summit on Thursday, March 20, 2025 at 03:15 PM.
This talk will be presented at the APS Global Physics Summit on Monday, March 17, 2025 at 11:30 AM.
Upcoming online presentation . This topic goes back to my M.Sc. thesis, when my supervisor, Prof. Christie Eliezer (2nd from left in the photo), who was one of Dirac's very few research students, told me about the Dirac-Sommerfeld paradox. He thought it might be pertinent to my thesis. Being a physics "genius", I didn't pursue it because I assumed it had been resolved by more modern developments…
I learnt about this interesting blog post entitled, "Discovering Hard Disk Physical Geometry through Microbenchmarking" by Henry Wong (2019) via TanelPoder on Twitter. As the title suggests, it is about applying so-called disk drive microbenchmarking to reveal information about the internal mechanical configuration and data layout that is not typically available with other HDD microbenchmark…
PDQ (Pretty Damn Quick) is a free, open source, performance analyzer available from the Performance Dynamics web site . All modern computer systems, no matter how complex, can be thought of as a directed graph of individual buffers that hold requests until to be serviced at a shared computational resource, e.g., a CPU or disk. Since a buffer is just a queue, any computer infrastructure, from your…
Giving Thanks for the release of PDQ 7.0 , after a 5-year drought, and just in time for the PDQW workshop next week. New Featues The introduction of the STREAMING solution method for OPEN queueing networks. (cf. CANON, which can still be used). The CreateMultiNode() function is now defined for CLOSED queueing networks and distinguished via the MSC device type (cf. MSO for OPEN networks). The…
PDQ (Pretty Damn Quick) is a queueing graph performance analyzer that comes as: free open source software package with an online user manual As shown in the above diagram, any modern computer system can be thought of as a directed graph of individual buffers where requests wait to be serviced at some kind of shared computational resource, e.g., a CPU or disk. Since a buffer is just a queue, any…
This is really more of a note-to-self but it may also be useful for other readers. Converting between various time zones, including UTC time, is both a pain and error-prone. A better solution is to use absolute time. Thankfully, Unix provides such a time: the so-called Epoch time , which is the integer count of the number of seconds since January 1, 1970. Timestamps are both very important and…
Writing a technical book is a difficult undertaking. As a technical author myself, I know that writing well is both arduous and tedious. There are no shortcuts. Over the last 40 years or so, computer-based tools have been developed to help authors write printed textbooks, monographs and technical articles. LaTeX (pronounced lar-tek ) reigns supreme in that realm because it's not just word…
" Applying The Universal Scalability Law to Distributed Systems " DSConf'19 - Distributed Systems Conference (scroll down) Pune, India 11am IST February 16 I'm very much looking forward to this event and I thank @ShrivedAgashe for the invitation.
All Guerrilla training classes are now open for registration . GCAP: Guerrilla Capacity and Performance — From Counters to Containers and Clouds GDAT: Guerrilla Data Analytics — Everything from Linear Regression to Machine Learning PDQW: Pretty Damn Quick Workshop — Personal tuition for performance and capacity mgmt The following highlights indicate the kind of thing you'll learn. Most especially,…
If you were unable to attend the live presentation on cost-effective defenses against chargeback in the cloud , or simply can't get enough performance and capacity analysis for the AWS cloud (which is completely understandable), here's a direct link to the video recording on CMG's YouTube channel. The details concerning how you can do this kind of cost-benefit analysis for your cloud applications…
NOTE: Annoyingly, the remote mathjax server often takes it's sweet time rendering LaTex equations (like, maybe a minute!!!). I don't know if this is deliberate on the part of Google or a bug. It used to be faster. If anyone knows, I'd be interested to hear; especially if there is a way to speed it up. And no, I'm not planning to move to WordPress. Update of Oct 2018: Wow! MathJax performance is…
... AKA hyperbolae . Here's a mnemonic tabulation based on dishes and bowls : Hopefully this makes amends for the more complicated explanation I wrote for CMG back in 2009 entitled: "Mind Your Knees and Queues: Responding to Hyperbole with Hyperbolæ" , which I'm pretty sure almost nobody understood.
Our abstract has been accepted for presentation at the FREE cloudXchange online event to be held by CMG on June 19th at 10am Pacific (5pm UTC). [ Extended slides ] Exposing the Cost of Performance Hidden in the Cloud Neil Gunther Performance Dynamics, Castro Valley, California Mohit Chawla Independent Systems Engineer, Hamburg, Germany 10am Pacific Time on June 19, 2018 Whilst offering…
A conversation with performance and capacity management veteran Boris Zibitsker, on his BEZnext channel , about how to save multiple millions of dollars with a one-line performance model (at 21:50 minutes into the video) that has less than 5% error. I wish my PDQ models were that good. :/ The strength of the model turns out to be its explanatory power, rather than prediction, per se. However, with…
This post seems like it ought to be too trite to write but, I see the following performance gotcha cropping up over and over again. Under pressure to consolidate resources, usually driven by management and especially regarding processor capacity, there is often an urge to "use up" any idle processor cycles. Idle processor capacity tends to be viewed like it's whitespace on a written…
This year offers a new 3-day class on applying PDQ in your workplace. The classic Guerrilla classes, GCAP and GDAT , are also being presented. Who should attend? architects application developers performance engineers sys admins test engineers mainframe sysops database admins webops anyone interested in getting beyond ad hoc performance analysis and capacity planning skills Some course highlights:…
The following abstract has been accepted for presentation at the 21st Conference of the International Federation of Operational Research Societies — IFORS 2017, Quebec City, Canada . Update July 31, 2017: Here are my IFORS slides Update June 08, 2018: In response to an audience question at my IFORS 2017 session, I have now demonstrated that there is an upper bound for the error in the…
Update of Thursday, August 17, 2017: It's looks like we can chalk up another one for the scale-free model (described below) as Github apparently surpasses 20 million users. Outgoing CEO Wanstrath mentioned this number in an emailed statement to Business Insider . "As GitHub approaches 700 employees, with more than $200M in ARR, accelerating growth, and more than 20 million registered users, I'm…
Our paper entitled, How to Emulate Web Traffic Using Standard Load Testing Tools (PDF) is now available online and will be presented at the upcoming CMG conference in November . Presenter : James Brady (co-author: Neil Gunther) Session Number : 436 Subject Area : APM Session Date : Wed, November 9, 2016 Session Time : 1:00 PM - 2:00 PM Session Room : PortofinoB The motivation for this work harks…
During the Guerrilla Data Analysis class last week, alumnus Jeff P. came up with this novel mnemonic device for remembering all three forms of Little's law that relate various queueing metrics to the mean arrival rate $\lambda$. The right-hand side of each equation representing a version of Little's law is written vertically in the order $R, W, S$, which matches the expression $R=W+S$ for the mean…