Mark H Weaver <m...@netris.org> skribis: > When hydra evaluates a jobset, 'package-transitive-supported-systems' is > called for every package+system combination. Each of these calls > traverses the tree of inputs, but without eliminating duplicate > transitive-inputs. In other words, the amount of time spent is > proportional not to the number of transitive-inputs, but the number of > _paths_ to all transitive-inputs.
Oops! Though it’s not clear to me that it explains the problems we’re seeing on Hydra currently, because running build-aux/hydra/gnu-system.scm on my laptop takes ~1mn. > This patch memoizes 'package-transitive-supported-systems', so that the > total time to apply it to all packages is O(N). Much better. > From 90541f6c7e2a9e2f8a7b412532b4b5a56a10e481 Mon Sep 17 00:00:00 2001 > From: Mark H Weaver <m...@netris.org> > Date: Sun, 21 Dec 2014 16:21:02 -0500 > Subject: [PATCH] Optimize package-transitive-supported-systems. > > * guix/packages.scm (first-value): Remove. > (define-memoized/v): New macro. > (package-transitive-supported-systems): Rewrite. LGTM, thank you! Ludo’.
