01/11: size: Optimize dependency size computation.

[guix-commits]

civodul pushed a commit to branch master
in repository guix.

commit 1199da08aa76f7bba57692b4b8e9272fd305e9f2
Author: Ludovic Courtès <address@hidden>
Date:   Sat Apr 6 14:52:56 2019 +0200

    size: Optimize dependency size computation.
    
    This reduces 'guix size' run time by ~4% here:
    
      items="$(guix build icecat inkscape emacs libreoffice)"
      guix size $items
    
    * guix/scripts/size.scm (store-profile): Define 'size-table' and use it
    to lookup the size of ITEM in 'dependency-size'.
---
 guix/scripts/size.scm | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/guix/scripts/size.scm b/guix/scripts/size.scm
index 25218a2..f549ce0 100644
--- a/guix/scripts/size.scm
+++ b/guix/scripts/size.scm
@@ -1,5 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2015, 2016, 2017, 2018 Ludovic Courtès <address@hidden>
+;;; Copyright © 2015, 2016, 2017, 2018, 2019 Ludovic Courtès <address@hidden>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -34,6 +34,7 @@
   #:use-module (srfi srfi-37)
   #:use-module (ice-9 match)
   #:use-module (ice-9 format)
+  #:use-module (ice-9 vlist)
   #:export (profile?
             profile-file
             profile-self-size
@@ -142,11 +143,20 @@ profile of ITEMS and their requisites."
                                            (lambda (size)
                                              (return (cons item size)))))
                                     refs)))
+    (define size-table
+      (fold (lambda (pair result)
+              (match pair
+                ((item . size)
+                 (vhash-cons item size result))))
+            vlist-null sizes))
+
     (define (dependency-size item)
       (mlet %store-monad ((deps (requisites* (list item))))
         (foldm %store-monad
                (lambda (item total)
-                 (return (+ (assoc-ref sizes item) total)))
+                 (return (+ (match (vhash-assoc item size-table)
+                              ((_ . size) size))
+                            total)))
                0
                (delete-duplicates (cons item deps)))))