[PATCH v2 0/6] kbuild: optimize output directory creation

[Masahiro Yamada]

I looked into the build scripts, focusing on "mkdir" optimization.

With this series, I succeeded in speeding up the incremental build
with O= option.

The following is the result of "time make O=foo",
where "foo" is the output directory that has already been built.

Before:

real    0m8.322s
user    0m4.324s
sys     0m1.220s

After:

real    0m6.989s
user    0m4.168s
sys     0m1.080s

4/6 gave the biggest impact.



Masahiro Yamada (6):
  kbuild: create directory for make cache only when necessary
  kbuild: remove redundant $(wildcard ...) for cmd_files calculation
  kbuild: filter-out PHONY targets from "targets"
  kbuild: create object directories simpler and faster
  kbuild: optimize object directory creation for incremental build
  kbuild: remove redundant mkdir from ./Kbuild

 Kbuild                       |  2 --
 Makefile                     |  3 +--
 arch/x86/entry/vdso/Makefile |  4 ----
 scripts/Kbuild.include       | 13 +++++++++----
 scripts/Makefile.build       | 25 +++++++++++++------------
 scripts/Makefile.headersinst |  3 +--
 scripts/Makefile.host        | 12 ------------
 scripts/Makefile.lib         |  5 -----
 scripts/Makefile.modpost     |  3 +--
 9 files changed, 25 insertions(+), 45 deletions(-)

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2.7.4