Re: powerpc allyesconfig / allmodconfig linux-next next-20160729 - next-20160729 build failures

Nicholas Piggin
2016-08-11T13:12:52Z

On Thu, 11 Aug 2016 15:04:00 +0200
Arnd Bergmann <arnd@arndb.de> wrote:

> On Thursday, August 11, 2016 10:43:20 PM CEST Nicholas Piggin wrote:
> > On Wed, 03 Aug 2016 22:13:28 +0200

> > Final ld time
> > inclink
> > real 0m0.378s
> > user 0m0.304s
> > sys 0m0.076s
> >
> > thinarc
> > real 0m0.894s
> > user 0m0.684s
> > sys 0m0.200s
>
> This also still seems fine.
>
> > For both cases final link gets slower with thin archives. I guess there is some
> > per-file overhead but I thought with --whole-archive it should not be that much
> > slower. Still, overall time for main ar/ld phases comes out about the same in
> > the end so I don't think it's too much problem. Unless ARM blows up significantly
> > worse with a bigger config.
>
> Unfortunately I think it does. I haven't tried your latest series yet,
> but I think the total time for removing built-in.o and relinking went
> up from around 4 minutes (already way too much) to 18 minutes for me.
>
> > Linking with thin archives takes significantly more time in bfd hash lookup code.
> > I haven't dug much further yet.
>
> Can you try the ARM allyesconfig with thin archives? I'll follow up with two
> patches: one to get ARM to link without thin archives, and one that I used
> to get --gc-sections to work.

Okay send them over, I'll try digging into it. There is not much kbuild
code to maintain so we don't have to switch every arch. It would be nice
to though.

Thanks,
Nick