Re: Estimating build time

[Efraim Flashner <efraim@flashner.co.il>]

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On Sat, Oct 13, 2018 at 01:13:17AM +0200, Clément Lassieur wrote:
> Ludovic Courtès <ludo@gnu.org> writes:
> 
> > In a similar vein, the attached module provides code to estimate package
> > build time based on locally-available build logs.  It can be used to
> > show hints like this:
> 
> [...]
> 
> > The obvious downside is that it works by first retrieving the names of
> > the files under /var/log/guix/drvs, and then opening, decompressing, and
> > parsing the candidate log files.  That typically takes a few seconds on
> > a recent SSD laptop, but clearly we don’t want to do that every time.
> > We could maintain a cache, but even then, it might still be too
> > expensive.
> >
> > Perhaps we should keep build times in the database somehow; the daemon
> > can keep it up-to-date.
> >
> > Thoughts?
> >
> > There’s the obvious downside that both approaches rely on having
> > previously built the package, but I think that’s a necessary limitation,
> > unless we are to resort to external services (which could hardly provide
> > estimates that make sense for the user’s machine anyway.)
> 
> I think it's an excellent idea!  I agree that the downside is necessary,
> and yes, keeping the build times in the database sounds good!
> 

One option would be, if it were a daemon-handled thing, to have it
configurable with a flag.

Off the top of my head, the linux from scratch documentation lists the
build times in units of binutils build time.

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Efraim Flashner   <efraim@flashner.co.il>   אפרים פלשנר
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