This website is dedicated to Linux performance, with a specific interest in Linux under VM. This is a commercial site used to communicate performance hints and tips, case studies, existing technologies, and product information. Velocity Software provides performance monitoring products for VM, including VM/XA, VM/ESA and z/VM. Performance monitoring includes network data collection, analysis and display, using our ESATCP, ESAMON and ESAMAP products. Display functions have been ported to use our web server ESAWEB.
The Scheduler is Always right, you just have to understand what it does. What you learn drinking beer with the engineer that supported the scheduler - it does what you tell it. But VERY few people understand that - and any time we hear "SET RELATIVE 10000", we wonder if anybody bothered to understand how it really works? See Rob's SET SHARE analysis and then revisit your shares and see if you are talking the right language.
Linux Steal Time - what is it? See Rob's paper on steal time.
Linux CPU reporting
under VM is WRONG! When running in a virtual environment
such as z/VM, ALL linux CPU accounting is wrong. This presentation
has been given many times at SHARE and IBM technical conferences,
but yet people want to depend on such
programs as "top" or "rmfpm" to provide their CPU Measurements.
For more explanation, see "top is bad" for details.
The standard presentation showing these numbers off by a factor of 10 can be found in the standard AFS Case Study presentation on the Velocity Software presentation page.
Velocity Software announces its Linux Performance Suite (ESALPS).For an overview, view a recent presentation given by the President of Velocity Software, Barton Robinson.
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