[www] r176209 - Add LNT statistics project

[Renato Golin]

On 1 March 2013 14:31, David Tweed <david.tweed at arm.com> wrote:

> (noise can make you slower, it can't make you faster)
>

I disagree.

Noise that makes you slower is context-switch, I/O stalls, device drivers,
hypervisors. But there's also noise that makes you much faster, like
accidentally well placed cache lines, OS cache for lookups, memory maps,
etc.

What you're calling "program speed" is the fastest the program can go,
assuming there is no OS, but when the OS interferes, you can go much faster
(open a browser, close and open again) or much slower (as we all know).

Bare metal noise's standard deviation up (slow) is definitely higher than
down (faster), but when OSs are in play, especially with out-of-order CPUs
like the A9, I wouldn't jump to conclusions.


> But to be honest I'm sure someone must have figured out the pros and cons
of various stats for benchmarking

Benchmarking is art, not science. Each with its own school(s), ideas,
beliefs. We could devote our entire lifetimes discussing this and we'd
still be arguing. ;)


cheers,
--renato
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