[OE-core] [PATCH] kernel: Use hardlinks during do_install for speed

[Andrea Adami]

On Fri, Nov 8, 2013 at 5:53 PM, Richard Purdie
<richard.purdie at linuxfoundation.org> wrote:
> On Fri, 2013-11-08 at 16:48 +0000, Hart, Darren wrote:
>> On Fri, 2013-11-08 at 15:17 +0000, Richard Purdie wrote:
>> > Whilst the comment says we can't do this, its incorrect, install operates
>> > on WORKDIR and its hard for different parts of WORKDIR to be on different
>>
>> Is it hard? Or is it not possible / not supported?
>
> Not really possible unless you try very hard. Its not supported. We
> don't even support WORKDIR and sysroot on different disks really.
>
>> My understanding was it was possible and therefor we couldn't hardlink.
>> I'm thrilled at the prospect of being wrong there though!
>
> I'm happy enough to decide we don't support it (and we never have).
>
>> > filesystems. Hardlinking instead of copying is therefore a nice performance
>> > gain.
>> >
>> > Also, completely skip the Documentation directory (adding a dummy Makefile
>> > to keep make happy) and tweak the other cp commands to link since if we
>> > don't we'd get "this is the same file" type errors from cp for some kernel
>> > versions.
>> >
>> > For do_install on linux-yocto, this takes it from 227s -> 84s.
>>
>> This, and the others, are fantastic improvements, thanks RP!
>
> I'm rather happy to find something we can easily fix :)
>
> Cheers,
>
> Richard
>
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On my old quad core:

Before: 131.01 seconds
After: 102.29 seconds

Thanks

Andrea