Re: [PATCH 00/23] kbuild: significantly speed up kernel builds

[Lorenzo Stoakes (ARM)]

On Fri, Sep 11, 2026 at 11:44:37PM -0700, Nathan Chancellor wrote:
> On Fri, Sep 11, 2026 at 12:28:34PM +0100, Lorenzo Stoakes (ARM) wrote:
> > On Wed, Sep 09, 2026 at 02:58:59PM -0700, Florian Fainelli wrote:
> > > On 9/8/26 13:55, Lorenzo Stoakes (ARM) wrote:
> > > > A typical kernel build consists of a frustratingly large amount of time
> > > > spent stuck in single-threaded bottlenecks.
> > > >
> > > > It turns out that there's a lot we can do about this and doing so
> > > > significantly impacts kernel build times.
> > > >
> > > > This series makes allmodconfig builds up to 36% faster, incremental builds
> > > > up to ~70% faster, and noop builds up to ~90% faster.
> > > >
> > > > Builds are faster across the board on every device I tested.
> > > >
> > > > Machines used for perf testing:
> > > >
> > > > * Threadripper -   x86, AMD Threadripper 9980X, 64 cores, 128 threads
> > > > * EPYC         -   x86, 2 socket EPYC 9754, 256 cores, 512 threads
> > > > * M2           - arm64, 2022 M2 macbook pro, 8 cores, 8 threads
> > > >                          (4 perf, 4 efficiency)
> > >
> > > My AMD EPYC 9454P server shows an improvement in the order of 13% using the
> > > arm64's defconfig and make -j97. Thanks for doing this!
> >
> > Nice thanks! Good to confirm others are seeing the benefits :)
>
> I see similar gains on an 80-core Ampere Altra system
>
>   6h 21m 42s -> 5h 31m 15s (-13.22%)
>
> and a 32-core AMD system.
>
>   3h 38m 55s -> 3h 13m 18s (-11.7%)
>
> The build matrices were different between machines but it is good to see
> similar numbers across different environments.

Nice, yes for sure!

>
> --
> Cheers,
> Nathan

--
Cheers, Lorenzo