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

[Nathan Chancellor]

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.

-- 
Cheers,
Nathan