classes/image: Use xargs to set file timestamps

Instead of having find directly invoke touch for each file in the root
file system, pass a list to xargs for batching. This significantly
reduces the number of times the touch program is invoked and speeds up
the do_image task time:

    PKG           TASK      ABSDIFF  RELDIFF  CPUTIME1 -> CPUTIME2
    my-image      do_image   -45.3s   -94.2%     48.1s -> 2.8s

    Cumulative cputime:
      -44.3s    -92.3%    00:48.1 (48.1s) -> 00:03.7 (3.7s)

Signed-off-by: Joshua Watt <JPEWhacker@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit 15c65f90a3aa1e98c2beab2539403157df1fca08)
Signed-off-by: Steve Sakoman <steve@sakoman.com>

diff --git a/meta/classes/image.bbclass b/meta/classes/image.bbclass
index 79c487ea18d250fe0de6569b6972b0445c8157ec..98513ddf084219f984023b0133713c4e3a7281ae 100644 (file)
--- a/meta/classes/image.bbclass
+++ b/meta/classes/image.bbclass
@@ -662,7 +662,7 @@ reproducible_final_image_task () {
         fi
         # Set mtime of all files to a reproducible value
         bbnote "reproducible_final_image_task: mtime set to $REPRODUCIBLE_TIMESTAMP_ROOTFS"
-        find  ${IMAGE_ROOTFS} -exec touch -h  --date=@$REPRODUCIBLE_TIMESTAMP_ROOTFS {} \;
+        find  ${IMAGE_ROOTFS} -print0 | xargs -0 touch -h  --date=@$REPRODUCIBLE_TIMESTAMP_ROOTFS
     fi
 }