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Yann E. MORIN df8d52fb02 package-infra: limit the number of // jobs
The current code spawns as many jobs as up to twice the number of CPUs.

On small-class machines like laptops, with a limitted amount of memory,
but still a few CPUs (real or hyperthreads), the HDD becomes a bottleneck,
and it becomes almost impossible to do anythiong else while there is a
build in progress.

Limit the number of jobs to the number of CPUs plus one.

Even on fast machines with fast HDDs, this settings keeps the machine
fully busy (for those packages that can build in parallel, of course).

For example, building qemu or the linux kernel kept my hyperthreaded
hexa Core i7 with 18GiB of RAM, busy at 99% (I never ever managed to
get 100% even with more jobs, not even 200); while on my hyperthreaded
dual Core i5 with only 4GiB and a slow HDD, I still topped at 100% CPU,
while still able to do some work involving the HDD.

If the number of processors is not available, assume one.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Nathan Lynch <ntl@pobox.com>
Reviewed-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Reviewed-by: Nathan Lynch <ntl@pobox.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2013-05-11 22:49:59 +02:00
arch arch: toolchain: Introduce binary format FLAT types. 2013-05-05 22:54:37 +02:00
board configs: add defconfig for Atmel AT91SAM9260-EK Nand Flash Boot 2013-05-11 22:34:32 +02:00
boot uboot: add custom version option 2013-05-07 09:26:04 +02:00
configs configs: add defconfig for Atmel AT91SAM9260-EK Nand Flash Boot 2013-05-11 22:34:32 +02:00
docs Update for 2013.05-rc1 2013-05-08 15:51:45 +02:00
fs packages: add ability for packages to create users 2013-04-25 22:56:42 +02:00
linux linux: bump 3.9.x stable version 2013-05-08 12:47:46 +02:00
package package-infra: limit the number of // jobs 2013-05-11 22:49:59 +02:00
support arc: Add arc, arcbe to gnuconfig 2013-05-04 23:23:26 +02:00
system system: remove trailing tabs in Config.in file 2013-04-29 22:56:57 +02:00
toolchain toolchain-external: fix bug #5054 2013-05-11 21:52:22 +02:00
.defconfig buildroot: get rid of s390 support 2009-01-12 14:36:14 +00:00
.gitignore update gitignore 2013-05-04 12:41:55 +02:00
CHANGES toolchain-external: fix bug #5054 2013-05-11 21:52:22 +02:00
Config.in rework patch model 2013-03-19 23:10:49 +01:00
Config.in.legacy arch: toolchain: Introduce binary formats BINFMT_*. 2013-05-05 22:46:37 +02:00
COPYING clarify license and fix website license link 2009-05-08 09:29:41 +02:00
Makefile Update for 2013.05-rc1 2013-05-08 15:51:45 +02:00
Makefile.legacy legacy: add error target for host-pkg-config 2012-11-30 12:07:09 -08:00

To build and use the buildroot stuff, do the following:

1) run 'make menuconfig'
2) select the packages you wish to compile
3) run 'make'
4) wait while it compiles
5) Use your shiny new root filesystem. Depending on which sort of
    root filesystem you selected, you may want to loop mount it,
    chroot into it, nfs mount it on your target device, burn it
    to flash, or whatever is appropriate for your target system.

You do not need to be root to build or run buildroot.  Have fun!

Offline build:
==============

In order to do an offline-build (not connected to the net), fetch all
selected source by issuing a
$ make source

before you disconnect.
If your build-host is never connected, then you have to copy buildroot
and your toplevel .config to a machine that has an internet-connection
and issue "make source" there, then copy the content of your dl/ dir to
the build-host.

Building out-of-tree:
=====================

Buildroot supports building out of tree with a syntax similar
to the Linux kernel. To use it, add O=<directory> to the
make command line, E.G.:

$ make O=/tmp/build

And all the output files (including .config) will be located under /tmp/build.

More finegrained configuration:
===============================

You can specify a config-file for uClibc:
$ make UCLIBC_CONFIG_FILE=/my/uClibc.config

And you can specify a config-file for busybox:
$ make BUSYBOX_CONFIG_FILE=/my/busybox.config

To use a non-standard host-compiler (if you do not have 'gcc'),
make sure that the compiler is in your PATH and that the library paths are
setup properly, if your compiler is built dynamically:
$ make HOSTCC=gcc-4.3.orig HOSTCXX=gcc-4.3-mine

Depending on your configuration, there are some targets you can use to
use menuconfig of certain packages. This includes:
$ make HOSTCC=gcc-4.3 linux-menuconfig
$ make HOSTCC=gcc-4.3 uclibc-menuconfig
$ make HOSTCC=gcc-4.3 busybox-menuconfig

Please feed suggestions, bug reports, insults, and bribes back to the
buildroot mailing list: buildroot@uclibc.org