Hi all,
I have done some investigation on LTO usage and current status, summarize as below:
1. LTO is still only an experimental feature and not accepted by upstream yet; 2. to enable LTO, we need apply 20+ patches from Andi Kleen's github repo; 3. we need at least 4GB(8GB+ may be better) RAM for LTO kernel building, and using gcc 4.9+(maybe gcc rebuild needed); 4. kernel building may take much longer time, A few kernel features are currently incompatible with LTO.
So my conclusion on this is: LTO is still on experimental stage, we can try use it for specific customer project but not the goal of upstream yet; BTW, LTO is a kernel general feature, there is no help for upstream ALSA specific tinification to try on it.
References: https://github.com/andikleen/linux-misc/blob/lto-4.0/Documentation/lto-build http://www.halobates.de/kernel-lto.pdf
thanks, ~Keyon
-----Original Message----- From: Jie, Yang Sent: Tuesday, October 13, 2015 9:34 AM To: Jaroslav Kysela; alsa-devel@alsa-project.org Subject: RE: [alsa-devel] Audio Mini Summit 2015, 8th October, Dublin
Thanks for pointing out this, Takashi, Lars, and Jaroslav.
I will try this LTO firstly and see what will happen.
Thanks, ~Keyon
-----Original Message----- From: alsa-devel-bounces@alsa-project.org [mailto:alsa-devel- bounces@alsa-project.org] On Behalf Of Jaroslav Kysela Sent: Tuesday, October 13, 2015 12:21 AM To: alsa-devel@alsa-project.org Subject: Re: [alsa-devel] Audio Mini Summit 2015, 8th October, Dublin
Dne 12.10.2015 v 17:54 Lars-Peter Clausen napsal(a):
E.g. I'd consider parameter refining a vital part of ALSA and the core functionality of it is rather compact. But it provides a lot of helper functions of which only some are going to be used if you built a reduced kernel. So rather then completely disabling parameter refining use LTO to remove the unused helper functions.
I agree. It sounds like perfect solution for optimized kernel builds.
Jaroslav-- Jaroslav Kysela perex@perex.cz Linux Sound Maintainer; ALSA Project; Red Hat, Inc. _______________________________________________ Alsa-devel mailing list Alsa-devel@alsa-project.org http://mailman.alsa-project.org/mailman/listinfo/alsa-devel