[U-Boot] [PATCH v3] Allow for parallel builds and saved output

[Albert ARIBAUD]

Hi Andy,

Le 25/04/2012 07:33, Andy Fleming a écrit :
> The MAKEALL script cleverly runs make with the appropriate options
> to use all of the cores on the system, but your average U-Boot build
> can't make much use of more than a few cores.  If you happen to have
> a many-core server, your builds will leave most of the system idle.
>
> In order to make full use of such a system, we need to build multiple
> targets in parallel, and this requires directing make output into
> multiple directories. We add a BUILD_NBUILDS variable, which allows
> users to specify how many builds to run in parallel.
> When BUILD_NBUILDS is set greater than 1, we redefine BUILD_DIR for
> each build to be ${BUILD_DIR}/${target}. Also, we make "./build" the
> default BUILD_DIR when BUILD_NBUILDS is greater than 1.
>
> MAKEALL now tracks which builds are still running, and when one
> finishes, it starts a new build.
>
> Once each build finishes, we run "make tidy" on its directory, to reduce
> the footprint.
>
> As a result, we are left with a build directory with all of the built
> targets still there for use, which means anyone who wanted to use
> MAKEALL as part of a test harness can now do so.
>
> Signed-off-by: Andy Fleming<afleming at freescale.com>
> ---
> v2:	- Update to keep BUILD_NBUILDS builds in flight, rather than batching
> 	- Clean up style things
> 	- Defer error output until build completion to make output *slightly*
> 	more readable
>
> v3:	- Add BUILD_MANY variable to clarify logic
> 	- Added comment for done/skip prefixes, and renamed for clarity
> 	- Changed CURRENT_COUNT to CURRENT_CNT to match TOTAL_CNT
> 	- Put build wait logic into its own manage_build function
> 	- Used wildcards to delete build management files
> 	- Fixed a bug where error-less builds printed an error

For ./MAKEALL arm, using cs2011-09, 7 builds 1 cpu on a 8 thread machine:

real	29m20.272s
user	95m59.708s
sys	10m17.383s

without the patch, and

real	20m26.480s
user	100m1.155s
sys	8m34.988s

with it, so there is definitely a benefit.

*However*, two boards build without and do not build clean with: scpu 
and pndb3.

Also, the final report is not displayed as the same with and without the 
patch -- with it, unclean boards are listed one per line, without it, 
they are listed in a single line.

Last: breaking during a parallel build then trying a git clean -xfd 
causes errors such as files missing.

Amicalement,
-- 
Albert.