Re: [PATCH] kbuild: switch to thin archives

[Pavel Machek]

On Mon 2017-06-19 17:45:21, Nicholas Piggin wrote:
> On Sun, 18 Jun 2017 12:04:26 +0200
> Pavel Machek <pavel@xxxxxx> wrote:
> 
> > On Fri 2017-06-02 22:54:54, Nicholas Piggin wrote:
> > > Switch from incremental build to thin archives for packaging built-in.o.
> > > binutils version must be bumped to 2.20. Proposed patch for 4.13.
> > > 
> > > Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx>  
> > 
> > You should explain any advantage this is supposed to have.
> 
> Hi Pavel,
> 
> You're right, sorry for this, I was spamming the list with a quick
> hack to try to get 0day to pick up the patch.
> 
> Most of the discussion has been going on in other patch series (check
> linux-kbuild).
> 
> There are 3 main categories of advantages.
> 
> First is reduced size of intermediate artifacts in the build output
> tree.
> 
> Second is that incremental linking constrains the linker because it
> has to assemble each section in the output as a sequence of those
> section from the inputs. So the more incremental linking, the more
> you constrain the linker, and this can end up resulting in link fail
> with large kernels on some architectures.
> 
> Third is that some link-time optimizations are not compatible or
> not very optimal with incremental linking, whereas thin archives
> is much more amenable to such things.

Thanks for explanation. I checked, and binutils version bumb will not
affect me, but...
									Pavel

-- 
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(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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