Using the pressure stall information interface in kernel 4.20

Fedora 29 now has kernel 4.20 available and it has lots of new features. One of the more interesting and easy to use features is the pressure stall information interface. Load average We’re all familiar with the load average measurement on Linux machines, even if the numbers do seem a bit cryptic: $ w 10:55:46 up 11 min, 1 user, load average: 0.42, 0.39, 0.26 The numbers denote how many processes were active over the last one, five and 15 minutes.
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Performance benchmarks: KVM vs. Xen

After having some interesting discussions last week around KVM and Xen performance improvements over the past years, I decided to do a little research on my own. The last complete set of benchmarks I could find were from the Phoronix Haswell tests in 2013. There were some other benchmarks from 2011 but those were hotly debated due to the Xen patches headed into kernel 3.0. The 2011 tests had a good list of benchmarks and I’ve done my best to replicate that list here three years later.
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Helpful Linux I/O stack diagram

During one of my regular trips to reddit, I stumbled upon an amazingly helpful Linux I/O stack diagram: It’s quite comprehensive and it can really help if you’re digging through a bottleneck and you’re not quite sure where to look. The original diagram is available in multiple formats from Thomas Krenn’s website. If you combine that with this slide from Brendan Gregg’s Linux Performance Analysis and Tools presentation from Scale 11x, you can attack performance problems with precision:
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Moving from OS X to Linux: Day One

The thought of using Linux as a manager in a highly Windows- and Mac-centric corporate environment isn’t something to be taken lightly. Integrating with Active Directory, wrangling email with Microsoft Exchange, and taming quirky Microsoft office documents can be a challenge even with a well-equipped Mac. I decided to make a change after using a Mac at Rackspace for six years. Let’s get one thing straight: I’m not a Windows or Mac basher.
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Red Hat Summit 2012: Thursday

Thursday has felt like the busiest, most jam-packed day of the week. The morning started off with three keynotes from HP, Intel, and Red Hat’s CTO, Brian Stevens. HP’s message centered around converged cloud and that customers don’t need an all or nothing solution. They can pull the best pieces from every type of hosting to do what’s best for their business. The presentation from Intel was extremely heavy on the marketing side and didn’t have much to do with Red Hat.
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