Re: comparing commit-relation using Scheme+libgit2 vs shellout plumbing Git

["Ludovic Courtès" <ludo@gnu.org>]

Simon Tournier <zimon.toutoune@gmail.com> skribis:

> On my machine, I get something less spectacular for a history with 1000
> commits in between.
>
> scheme@(guix-user)> ,time (commit-relation* 1000th newest)
> $1 = ancestor
> ;; 0.128948s real time, 0.082921s run time.  0.046578s spent in GC.
> scheme@(guix-user)> ,time (commit-relation 1000th newest)
> $2 = ancestor
> ;; 4.588075s real time, 5.521358s run time.  1.404764s spent in GC.
>
> I did something very similar as wolf is proposing and named it
> ’commit-relation*’.

That’s an order of magnitude.  Probably it could be a bit less if we put
some effort in it (‘commit-relation’ is implemented in a fairly naive
way.)

That said, ‘commit-relation’ is just one example.  I’d encourage
interested people to look at (guix git-authenticate) to get a feel of
what we need.  Most of it is quite pedestrian, like
‘load-keyring-from-reference’ or ‘commit-signing-key’, but I don’t think
we can get a decent throughput if we shell out for all these things
(assuming ‘git’ can even give us raw data).

Ludo’.