Re: Benchmark (Phoronix): FreeBSD 9.0-RC2 vs. Oracle Linux 6.1 Server

From: Igor Mozolevsky <igor_at_hybrid-lab.co.uk>
Date: Thu, 22 Dec 2011 10:50:49 +0000
On 22 December 2011 10:12, Daniel Kalchev <daniel_at_digsys.bg> wrote:

> As for how fast to get from point A to point B. If you observe speed limits,
> that will depend only on the pilot, no? :)
> Both cars are sufficiently faster than the imposed speed limits.

You are ignoring acceleration, handling, and other factors... Besides,
you're missing the point: *given same conditions* a benchmark allows
one to show how A performs compared to B, which is why I said it is
important to keep everything else constant! At the end of the day,
what users, sysadmins, &c want to know is given hardware configuration
H and requirement R will software X outperform software Y or Z. The
components and the bells and whistles of X, Y or Z are, quite often,
irrelevant (unless one has some silly idealogical reason, for
example).


> On very specific hardware, such as systems with many CPUs and lots of
> memory, you may see one better than the other -- this in most cases will be
> relevant to tuning, but also to overall system architecture.

Are you saying that careful tuning will give you _orders of magnitude_
performance increase? Got numbers to back that up? ;-)


> You may make an very "scientific", well documented and repeatable benchmark,
> such as this one:
>
> time dd if=/dev/zero of=/dev/null
>
> .. then optimize your particular OS to run it at the highest possible
> rate... and so what? Do you know what this benchmark measures? :)

Yes, do you? I hope you are not being deliberately obtuse here...
Besides, I would criticise your test in this example: have you tried
running that with, say, bs=1g count=1000? Is there a difference how
fast FreeBSD completes that vs how fast a Linux box does the same? The
point of documenting a repeatable benchmark is to enable the person
interpreting the results to see what was done (and verify) to achieve
the result and treat that result accordingly.

Cheers,

--
Igor
Received on Thu Dec 22 2011 - 09:51:30 UTC

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