Re: [gentoo-dev] Re: emerge suggestions

[Chris Gianelloni]

On Wed, 2004-09-08 at 19:46, Heiko Wundram wrote:
> Am Mittwoch, 8. September 2004 18:43 schrieb Chris White:
> > How are you going to effectively measure the times?
>
> IIRC, there once was a proposal to do this using bash-units. Each product in
> the tree gets assigned a bash unit, which is a floating point number >0 which
> measures how long compilation takes relative to compiling some certain
> version of bash.

Let's assume we'll just use bash-2.05 (or 3.0, doesn't matter).

> Now, all that needs to be done is to measure package compilation and merging
> time, divide by the number of bash units this package has, and you get an
> estimate on the time for a bash unit on this computer. The more packages you
> merge, the finer this number will become by simply averaging it out. Of
> course, this does not take into account changing the LDFLAGS (which should
> make up for the biggest part of different merge times), or CFLAGS (which
> might also change timing by varying optimization levels and swap
> requirement). But, anyway, these numbers don't change anything about the
> underlying unit, which should be to a large extent platform and machine
> independent.

That's pretty much accurate.  Another thing that could be done is there
could be a way to "calibrate" the system... essentially, performing a
bash build using the current {C,CXX,LD}FLAGS to get an accurate time. 
This measurement could then be used by portage in giving time estimates.

> I don't know when this proposal came up, I read about it on some forum, some
> time ago.

I know that I mentioned it a while back, but it had been said before
that, so I'm not taking credit (or blame ;p) for it.

-- 
Chris Gianelloni
Release Engineering - Operations/QA Manager
Games - Developer
Gentoo Linux

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