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From: Fabio Porcedda <fabio.porcedda@gmail.com>
To: buildroot@busybox.net
Subject: [Buildroot] [PATCH v12 6/7] Makefile: update comment about top-level parallel Makefile
Date: Wed, 12 Feb 2014 10:19:10 +0100	[thread overview]
Message-ID: <1392196751-23485-7-git-send-email-fabio.porcedda@gmail.com> (raw)
In-Reply-To: <1392196751-23485-1-git-send-email-fabio.porcedda@gmail.com>

After the latest patches top-level parallel Makefile is working but
there is still an issue when a package has an unspecified optional
dependency so change the comment to explain that.

Signed-off-by: Fabio Porcedda <fabio.porcedda@gmail.com>
---
 Makefile | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index c89107a..ddb1f6a 100644
--- a/Makefile
+++ b/Makefile
@@ -42,7 +42,20 @@ export HOSTARCH := $(shell uname -m | \
 	    -e s/macppc/powerpc/\
 	    -e s/sh.*/sh/)
 
-# This top-level Makefile can *not* be executed in parallel
+# Parallel execution of this Makefile is disabled because it changes
+# the packages building order, that can be a problem for two reasons:
+# - If a package has an unspecified optional dependency and that
+#   dependency is present when the package is built, it is used,
+#   otherwise it isn't (but compilation happily proceeds) so the end
+#   result will differ if the order is swapped due to parallel
+#   building.
+# - Also changing the building order can be a problem if two packages
+#   manipulate the same file in the target directory.
+#
+# Taking into account the above considerations, if you still want to execute
+# this top-level Makefile in parallel comment the ".NOTPARALLEL" line and
+# build using the following command:
+#	make BR2_JLEVEL= -j$((`getconf _NPROCESSORS_ONLN`+1))
 .NOTPARALLEL:
 
 # absolute path
-- 
1.8.5.4

  parent reply	other threads:[~2014-02-12  9:19 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-02-12  9:19 [Buildroot] [PATCH v12 0/7] Add support for top-level parallel make Fabio Porcedda
2014-02-12  9:19 ` [Buildroot] [PATCH v12 1/7] package: add base dependency to every package Fabio Porcedda
2014-02-12  9:19 ` [Buildroot] [PATCH v12 2/7] package: add toolchain dependency to every target package Fabio Porcedda
2014-02-12  9:19 ` [Buildroot] [PATCH v12 3/7] package: add support for top-level parallel make Fabio Porcedda
2014-02-13  6:58   ` Arnout Vandecappelle
2014-02-13  9:13     ` Fabio Porcedda
2014-02-12  9:19 ` [Buildroot] [PATCH v12 4/7] Makefile: " Fabio Porcedda
2014-02-12  9:19 ` [Buildroot] [PATCH v12 5/7] package: enable jobserver for recursive make Fabio Porcedda
2014-02-12  9:19 ` Fabio Porcedda [this message]
2014-02-12  9:19 ` [Buildroot] [PATCH v12 7/7] sdl: add support for top-level parallel make Fabio Porcedda
2014-02-13 14:52   ` Thomas Petazzoni
2014-02-14  8:58     ` Fabio Porcedda

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