Greg Smith <[EMAIL PROTECTED]> writes:
> On Wed, 25 Jul 2007, Tom Lane wrote:
>> Gentoo always leaves me wondering exactly what I'm running today,
>> and I think reproducibility is an important attribute for a benchmarking
>> machine.

> At this point, there's enough performance variations even between 
> individual Linux kernel releases that I'm not sure how much 
> reproducibility you're ever going to get here.  Are the differences 
> between Gentoo and RHEL any bigger than those, say, between RHEL and SuSE?

The problem I've got with Gentoo is that it encourages homegrown builds
with randomly-chosen options and compiler switches.  That may help
squeeze out a bit more speed but it does nothing for stability, nor
reproduceability of results on other platforms which is what we really
care about here.

Another fairly big issue is that we need to know whether measurements we
take in August are comparable to measurements we take in October, so a
fairly stable platform is important.  As you say, a fast-changing kernel
would make it difficult to have any confidence about comparability over
time.  That would tend to make me vote for RHEL/Centos, where long-term
stability is an explicit development goal.  Debian stable might do too,
though I'm not as clear about their update criteria as I am about Red Hat's.

> The idea of setting this up with a long-term stable distribution runs 
> counter to one of the things that I think is important to explore here, 
> which is testing how more recent Linux kernels have improved their 
> scalability.

Dunno if Gavin wants to manage multiple systems, but for most of what
I'd like to do a bleeding-edge kernel is exactly what I do not want.

                        regards, tom lane

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