Comments on: openSUSE@ARM/GSoC: Cross-compilation & speedup https://lizards.opensuse.org/2009/06/16/opensusearmgsoc-cross-compilation-speedup/ Blogs and Ramblings of the openSUSE Members Fri, 06 Mar 2020 17:50:09 +0000 hourly 1 https://wordpress.org/?v=4.7.5 By: Matt Sealey, Genesi USA https://lizards.opensuse.org/2009/06/16/opensusearmgsoc-cross-compilation-speedup/#comment-1197 Sun, 23 Aug 2009 19:52:11 +0000 http://lizards.opensuse.org/?p=1282#comment-1197 The simple reason for the speedup is that for your average 8-core or 16-core x86 build box, building an x86 package – even a very large one – can take only a few minutes. I can build a kernel for ARM using cross-compilation in less than 2 minutes, using -j10 parallel makes (it goes faster if I just use -j but I really do not like the way it impacts everyone else’s sessions 🙂

When you run a package build through QEMU you get a single emulated ARM processor running on a SINGLE PHYSICAL CPU core. The other 7-15 processors are sitting idle while this emulated box struggles to translate to x86 instructions and compile ARM code.

This is where the speedup comes from. Most of the problems with cross-compile builds are actually CAUSED by tools which are meant to take the problem away – GNU autoconf is a horrible mistake in design which allows developers to make cross-compilable packages but nobody is talented enough to script it correctly to make it work.

]]> By: martin.mohring@opensuse.org https://lizards.opensuse.org/2009/06/16/opensusearmgsoc-cross-compilation-speedup/#comment-1034 Tue, 16 Jun 2009 16:55:17 +0000 http://lizards.opensuse.org/?p=1282#comment-1034 The felt performance of qemu was quite slow – but it did not feel *that slow* acutally. Factor x15 for a package that takes already quite a while to build is much too slow.

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