Re: Recent slowdown in single object builds

[Masahiro Yamada]

On Sat, Nov 16, 2019 at 8:10 AM Jens Axboe <axboe@xxxxxxxxx> wrote:
>
> Hi,
>
> I've noticed that current -git is a lot slower at doing single object
> builds than earlier kernels. Here's an example, building the exact same
> file on 5.2 and -git:
>
> $ time make fs/io_uring.o
> real    0m5.953s
> user    0m5.402s
> sys     0m0.649s
>
> vs 5.2 based (with all the backports, identical file):
>
> $ time make fs/io_uring.o
> real    0m3.218s
> user    0m2.968s
> sys     0m0.520s
>
> Any idea what's going on here? It's almost twice as slow, which is
> problematic...



This is necessary cost
to do single builds
(394053f4a4b3e3eeeaa67b67fc886a9a75bd9e4d)
but, it is much better in linux-next.



-- 
Best Regards
Masahiro Yamada