01/01: packages: Enable threaded compression of source tarballs.

[Leo Famulari]

lfam pushed a commit to branch core-updates
in repository guix.

commit c8a3dea847bb9f87fa1876d0c6c3356d6226f121
Author: Leo Famulari <address@hidden>
Date:   Thu Mar 30 03:10:48 2017 -0400

    packages: Enable threaded compression of source tarballs.
    
    This provides a ~2x speedup when using 4 threads.
    
    * guix/packages.scm (patch-and-repack)[build]: Invoke xz with
    '--threads=0' when re-packing tarballs.
---
 guix/packages.scm | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/guix/packages.scm b/guix/packages.scm
index 61171b8..29351ac 100644
--- a/guix/packages.scm
+++ b/guix/packages.scm
@@ -576,7 +576,12 @@ specifies modules in scope when evaluating SNIPPET."
                                                     #:fail-on-error? #t)))))
                         (zero? (apply system*
                                       (string-append #+tar "/bin/tar")
-                                      "cvfa" #$output
+                                      "cvf" #$output
+                                      ;; The bootstrap xz does not support
+                                      ;; threaded compression (introduced in
+                                      ;; 5.2.0), but it ignores the extra flag.
+                                      (string-append "--use-compress-program="
+                                                     #+xz "/bin/xz 
--threads=0")
                                       ;; avoid non-determinism in the archive
                                       "address@hidden"
                                       "--owner=root:0"