Lightnews — Scholar-powered news

Dr. Neil Gunther @drqz.bsky.social · 3d

Productivity: If you want to be more productive, go to sleep.
www.perfdynamics.com/Manifesto/gc...

Dr. Neil Gunther @drqz.bsky.social · 11d

Some performance consequences often overlooked in redundancy plans
perfdynamics.blogspot.com/2014/03/perf...

Performance of N+1 Redundancy

How can you determine the performance impact on SLAs after an N+1 redundant hosting configuration fails over ? This question came up in the...

perfdynamics.blogspot.com

Dr. Neil Gunther @drqz.bsky.social · 28d

Out of The Queue Comes ... Amdahl’s Law!
www.perfdynamics.com/Papers/amdsy...

1 1

Dr. Neil Gunther @drqz.bsky.social · Aug 8

RIP James Lovell, commander of Apollo 13 (played by Tom Hanks in the movie of the same name), has died at age 97.

Dr. Neil Gunther @drqz.bsky.social · Aug 7

B. All measurements (data) are wrong ... by definition.
The only question is, can you tolerate the wrongness?
If you're not informed how wrong data is, how can you decide?

Dr. Neil Gunther @drqz.bsky.social · Aug 7

A. Displaying metrics, errors, etc., is not the same thing as displaying metric errors.
1. How it is (old school top)
CPU usage: 5.79 %usr, 4.51 %sys, 89.68 %idl
2. How it could be (nay, SHOULD be)
CPU usage: 5.79 ± 0.29 %usr, 4.51 ± 0.23 %sys, 89.68 ± 4.48 %idl

1

Dr. Neil Gunther @drqz.bsky.social · Aug 6

Online classroom buzz www.perfdynamics.com/Classes/comm...
What Guerrilla Grads are saying about why you should become an alumnus.
Enroll here www.perfdynamics.com/Classes/sche... 🎓

#performance #engineering #capacity #management #marketplace #trends #GCAP #GDAT #PDQW

3

Dr. Neil Gunther @drqz.bsky.social · Aug 5

BTW: the Editor-in-Chief is looking for assistant editors and reviewers. Email him at <[email protected]>

Dr. Neil Gunther @drqz.bsky.social · Aug 5

PSA: New open access Journal of Systems Scalability launching.
Editor-in-Chief: Carlos Juiz
www.icck.org/jss
#systems #architecture #performance #scalability

1

Dr. Neil Gunther @drqz.bsky.social · Aug 1

GCAP Day 10. What you missed:
❥ Avalanche vs. Paxos coordination scalability
❥ Memcache scalability analysis with USL
❥ Queueing models of Kubernetes control and data planes
❥ Class dismissed 📚 🎓🍻

Dr. Neil Gunther @drqz.bsky.social · Jul 31

Never let reality get in the way of a good performance model.

Dr. Neil Gunther @drqz.bsky.social · Jul 31

GCAP Day 9. What you missed:
❥ Rate limiting services via Guerrilla queueing models
❥ Performance visualization tools
❥ Zookeeper scalability analysis with the USL
www.perfdynamics.com/Manifesto/US...

Dr. Neil Gunther @drqz.bsky.social · Jul 30

GCAP Day 8. What you missed:
❥ Linear vs Dynamic programming
❥ Benchmarking/load testing prats and pitfalls
❥ Prelim discussion about Kefka, Kubernetes
❥ What kind of scheduler is in the K8s control plane?

Dr. Neil Gunther @drqz.bsky.social · Jul 29

GCAP Day 7. What you missed:
❥ Python least_squares() seems to be a bloated implementation of codes in the "Numerical Recipes" book.
❥ To apply the USL, use curve_fit() instead.
❥ Multivariate regression: How to reattach (noisy) fingers to amputated daily "numero uno" data

Dr. Neil Gunther @drqz.bsky.social · Jul 28

GCAP Day 6. What you missed:
❥ USL scalability analysis
lnkd.in/gxaaAiww
❥ Student gets PDQ 7.0 running on Python 3.12 👏🎉
lnkd.in/gPzzHiez
❥ Homework Q-5 solved (a) analytically (b) cf. with corresponding PyDQ model
- Discussed why analytic calculation was wrong

Dr. Neil Gunther @drqz.bsky.social · Jul 27

Ditto for the performance analysis & capacity planning of computer systems in general:
- Assume failure
- Plan for resilience
- Monitor everything
- Analyze and predict performance and capacity
- Have an exceptional performance team of skilled experts

lnkd.in/g8eGRnYq

1

Dr. Neil Gunther @drqz.bsky.social · Jul 25

RIP Chuck Mangione
www.youtube.com/watch?v=c4el...

Chuck Mangione - Feels So Good (The Old Grey Whistle Test, January 16th, 1979)

YouTube video by Chuck Mangione

www.youtube.com

Reposted by Dr. Neil Gunther

Dr. Neil Gunther @drqz.bsky.social · Jun 24

Guerrilla Capacity Planning (GCAP) Online
— EU Edition — registration is now OPEN
Dates: July 21 through August 1, 2025
Times: 1500 - 1900 CET
www.perfdynamics.com/Classes/sche...

Click on the DETAILS box (at the RHS) to register
www.eventbrite.com/e/guerrilla-...

1

Dr. Neil Gunther @drqz.bsky.social · Jul 3

#TIL Product Solutions Physicist 😳

Dr. Neil Gunther @drqz.bsky.social · Jul 1

I recently discovered the original 1992 paper where I first introduced the concept of barycentric coordinates for visualizing multiprocessor/multicore performance. www.perfdynamics.com/papers.pdf

More modern renditions (animations) can be viewed here www.perfdynamics.com/Tools/tools....

1

Dr. Neil Gunther @drqz.bsky.social · Jul 1

Yep.

Dr. Neil Gunther @drqz.bsky.social · Jun 27

Guerrilla training classes (GCAP) online are brutal.
Despite the rumors, there are no long lunches.
Only performance zealots should apply.
Next class starts July 21, 2025.

www.perfdynamics.com/Classes/sche...

#Performance #Training

Dr. Neil Gunther @drqz.bsky.social · Jun 24

Guerrilla Capacity Planning (GCAP) Online
— EU Edition — registration is now OPEN
Dates: July 21 through August 1, 2025
Times: 1500 - 1900 CET
www.perfdynamics.com/Classes/sche...

Click on the DETAILS box (at the RHS) to register
www.eventbrite.com/e/guerrilla-...

1

Dr. Neil Gunther @drqz.bsky.social · Jun 20

Even worse, without access to another phone or computer, you're really screwed. The longer it takes to contact Lyft, the lower the likelihood of ever seeing your phone again.

Thank God it wasn't BART.

Dr. Neil Gunther @drqz.bsky.social · Jun 20

Postscript: That sinking feeling when you realize 90% of your life is funneled through a 6"x3" piece of metal & silicon that has decided to escape from you, without permission.

1