[kwlug-disc] benchmark: performance on six cores = 1 on one core = 6

[Khalid Baheyeldin]

On Wed, Jun 2, 2010 at 7:08 PM, Richard Weait <richard at weait.com> wrote:

> Benchmarking a server application finks that performance is six times
> better when restricted to a single core
>
>
> http://mailinator.blogspot.com/2010/02/how-i-sped-up-my-server-by-factor-of-6.html
>

For long running processes, invalidating the CPU cache when a task switches
from one core (or socket) exacts a high toll, and this seems to be a case of
exactly that. Another case would be a long running compile.

For other workloads, which are short tasks, quick in, quick out (e.g.
serving
a web page), the penalty is not as high as that, since even web server
processes do not stick around for a long time on a server (to avoid leaks
and such).
-- 
Khalid M. Baheyeldin
2bits.com, Inc.
http://2bits.com
Drupal optimization, development, customization and consulting.
Simplicity is prerequisite for reliability. --  Edsger W.Dijkstra
Simplicity is the ultimate sophistication. --   Leonardo da Vinci
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