Linux Benchmarking

[Walter Dnes]

On Tue, Aug 23, 2005 at 06:05:17AM -0400, Scott Allen wrote

> You have to watch Gentoo. Being a source based system that makes it
> easy to choose the optimisation flags, a "best-tweaked" system can
> also become unstable.

  That's *NOT* my definition of "best tweaked".

> It might win in the benchmark tests but break certain common app's.
> (Of course you can modify the optimisation on a per app' basis if you
> want to get your hands just a little dirty).
> 
> To be a useful test though, I would think that you would want to compare
> stock-Slackware with "best-tweaked but still likely to be stable"...

  I call *THAT* "best tweaked".

> Gentoo without individual app' tuning.

  What about...

  - /etc/portage/package.keywords (allows to bring packages from outside
    the stable branch).  Even Debian allows, and sometimes requires, it.

  - /etc/portage/package.mask (lists stuff that is not allowed to
    pollute my system).  I've got "sys-libs/pam" in there.

  - /etc/portage/package.use  There are *VERY* few packages that need to
    be built with the "static" flag.  However, if busybox is going to be
    a "rescue package" when libraries get accidentally deleted, it damn
    well better be compiled static, so it can run standalone.

  - Some apps also have app-specific flags, listed in
    /usr/portage/profiles/use.local.desc, which can be implemented by
    including them in /etc/portage/package.use.  E.g. mplayer has a
    "realplayer" flag that affects what happens when it runs across a
    RealPlayer URL (which it can't handle).  Rather than exiting with an
    error flag, it fires up Real Player to handle the URL.

  I'm working on putting together YAF (Yet Another FAQ) for Gentoo
newbies.  It's almost as much of a HOW_NOT_TO as it is a HOW_TO.  It
will mention stuff like...
  - *NOT* unrolling every last single loop or implementing every last
    single exotic generic compiler "optimization"
  - *NOT* exceeding -O2
  - *NOT* exceeding "MAKEOPTS=-j1"
  - *NOT* using fbsplash until you have Gentoo up and running first.
    For that matter, avoid framebuffer altogether if you can.  This may
    not be an option on non-X86 architectures.
  - *NOT* using PAM unless you are already familiar with it.  Gentoo has
    a steep learning curve.  PAM has a steep learning curve.  Learning
    *BOTH OF THEM AT THE SAME TIME* is more like climbing up the side of
    a cliff.

-- 
Walter Dnes <waltdnes-SLHPyeZ9y/tg9hUCZPvPmw at public.gmane.org>
My musings on technology and security at http://tech_sec.blog.ca
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