Contents 1 Background and pointers 1.1 Background 1.2 Pointers on the cross build 1.3 Some figures

Background and pointers

Background

Different types of crossbuilding: http://en.opensuse.org/Build_Service/Concepts/CrossDevelopment#Types_of_Crossbuild

A bit terminology:

• pure native - builds on real hardware

• cross-compilation - as in traditional

• transparent emulation - qemu-arm is used for executing arm binaries on x86

• "native" + emulation - emulated execution without the use of cross-compiler or speedup

• "cross" + emulation - emulated execution with the use of cross-compiler and speedup

The default package list for a build environment is defined in the prjconf (see http://en.opensuse.org/Build_Service/prjconf) :

  Preinstall  +  Required + Support  +  Packages from dependency resolution

For the "native"+emulation cross-build (as in: without cross-compilers), we use qemu-arm. The callenge is now to keep the environment but add speed through cross-compilers (="cross"+emulation).

Pointers on the cross build

• http://en.opensuse.org/Build_Service/Concepts/CrossDevelopment

• http://lizards.opensuse.org/2009/01/27/build-maemo-apps-with-opensuse-buildservice-it-works/

• http://lizards.opensuse.org/2009/05/04/gsoc-introduction-opensusearm/

• http://wiki.maemo.org/Mer/Build/Cross_Build

Some figures

With all changes in place, we reach really good speed. E.g. for:

• package rpm

• package glibc w/o locales

Build time in minutes

	x86 native	armv5tel native	armv5tel cross		factor x86->arm native	factor x86->arm cross
rpm	8	107	17		13,38	2,13
glibc	33	505	63		15,3	1,91