lkml.org 
[lkml]   [2014]   [Apr]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [GIT] kbuild/lto changes for 3.15-rc1
On 2014.04.15 at 13:19 +0200, Sam Ravnborg wrote:
> >
> > And while the code size reduction is less for MIPS than what others have
> > reported for their platforms (I'm still investigating) is still is enough
> > that embedded developers would commit murder for.
>
> I have experimented a little with a patch that links all of vmlinux in one step.
> I compared the text size of vmlinux without and with -ffunction-sections.
>
> With a defconfig build on x86 (32 bit) I got following results:
>
> size difference
> singlelink 10266506
> function-sections 9487369 779137 7,5%
>
> So this is a reduction of ~800 kb by enabling -ffunction-sections which
> allows the linker to throw away unused sections.
>
> I have not boot tested the kernel so chances are that too much was thrown out by the linker.
> But this is an option that has much smaller cost to use than lto.
> And seems to benefit nicely in size.
>
> I have not tried this wihtout my singlelink patch - but I assume similar results.

No, it wouldn't work, because you cannot mix -r and --gc-sections (or
gold's --icf (identical code folding)).

--
Markus


\
 
 \ /
  Last update: 2014-04-15 14:21    [W:0.074 / U:3.672 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site