New Performance Papers from VMware

Two new performance whitepapers from VMware:

1. VMware vSphere 4: The CPU Scheduler in VMware ESX 4
   
2. Understanding Memory Resource Management in VMware ESX Server:
   

Both apply controlled measurements ("Experimental Environment"), as described in my latest Linux Technical Review article.

Performance und Virtualisierung

Autor: Neil J. Gunther
Erschienen: 15.09.2009
Umfang: 13 Seiten

Woran denkt man, wenn man den Begriff Virtualisierung hört? An einen Hypervisor wie Citrix XenServer oder den ESX-Server von VMware? Oder an virtualisierte Services wie beim Cloud Computing? Oder an Multicore-CPUs mit Hyperthreading, die virtuelle Prozessoren ermöglichen? Am besten betrachtet man all diese Erscheinungsformen von Virtualisierung nicht isoliert, sondern als Teile eines einzigen Performance-Management-Puzzles. Dieser Beitrag erklärt wieso und er unterstreicht, wie wichtig es ist, durch kontrollierte Performance-Messungen Daten zu sammeln.

"Virtualization in the Enterprise from the Performance Management Perspective"

When you see the word virtualization, what do you think of? Hypervisors like Citrix XenServer or VMware ESX? Perhaps you thought of virtualized services like cloud computing? What about hyperthreaded multicores that facilitate virtual processors? Rather than thinking of all these forms of virtualization as being completely different from one another, this article explains why it's better to think of them as being pieces of the same performance management puzzle.The importance of doing controlled performance measurements is also emphasized.

Linux Technical Review

Can Haz Guy: USA CIO Vivek Kundra

Columnist Chris O'Brien's interview with Vivek Kundra in the San Jose Mercury News, appears in "How new CIO has brought innovation to government" . . . "a quiet revolution in the way the federal bureaucracy works that may change our view of government for the better."

Anti Log Plots

A sure sign that somebody doesn't know what they're doing is, when they plot their data on logarithmic axes. Logarithmic plots are almost always the wrong thing to use. The motivation to use log axes often arises from misguided aesthetic considerations, rather than any attempt to enhance technical understanding, e.g., trying to "compress" a lot of data points into the available plot width on a page. The temptation to use log plots is also too easily facilitated by tools like Excel, where re-scaling the plot axes is just a button-click away.

This is Your Measurements on Models

When it comes to analyzing scalability data, I've stressed the importance of bringing measurements and models together. Some recent conversations with people who are just beginning to model their scalability data using the Universal Scalability Law (USL), have led me to realize that I have not made the steps behind the procedure as clear as I might have. So, let me address that here.

Seeing Molecules: Kekulé's Dream Writ Large

As a chemist in a former life, I can't help but comment on this watershed moment in science, even though it's probably been blogged to death. Nanotechnologists at IBM Zürich have imaged the naturally occurring organic molecule pentacene (essentially, 5 benzene ring-molecules bolted together in a row). Why is this a big deal?

Block The Emergency Exit for Faster Evacuations

NewScientist reports that Japanese physicists timed a crowd of 50 women(?) as they exited as fast as possible through a door. They then repeated the experiment with a 20 cm (10 inch) wide pillar placed 65 cm (2 feet) in front of the exit to the left-hand side. The obstacle increased the exit throughput by an extra seven people per minute.

"Usually, the exit becomes clogged by people competing for the small space, and the crowd is slowed. The pillar blocks pedestrians arriving at the exit from the left so effectively that the number of people attempting to occupy the space just in front of the exit is reduced, says Yanagisawa. With reduced crowding there are fewer conflicts and the outflow rate increases."

How does this apply to computer performance? Think polling systems, where there are multiple waiting lines or buffers but only one service facility, like a grocery store with the usual checkout lanes but only one cashier running between them! Would you want to shop in that store? In the physics experiment, the exit is the single server and the lines are the streams of people (women?) approaching the exit from all angles. The asymmetric placement of the pillar effectively reduces the number of exit streams that can form (I'm guessing).