Re: [PATCH v4 00/11] s390: More this_cpu_*() changes

[Mete Durlu]

On 22/09/2026 20:22, Heiko Carstens wrote:
> On Tue, Sep 22, 2026 at 05:37:14PM +0200, Mete Durlu wrote:
> > On 21/09/2026 17:57, Heiko Carstens wrote:
> > [..snip..]
> > > The only non-trivial patch is the last one, which converts s390's
> > > this_cpu_*() operations to use a similar scheme like Mark Rutland
> > > provided it for arm64 [1]. This allows to simplify the irq entry and exit
> > > path, however at the cost of slightly worse code for this_cpu_*()
> > > operations.
> ...
> > Hi all,
> >
> > I did some benchmarking for this patch series.
> >
> > Used a shared LPAR with 24 CPUs (12 cores w SMT2).
> >
> > Base commit: f0100363d8c3 ("Merge tag 'xfs-fixes-7.3-rc5' of
> > gitolite.kernel.org:/pub/scm/fs/xfs/xfs-linux")
> >
> > Some of the benchmark runs show +-5% standard deviation which can
> > be attributed to s390 being a virtualized system. Each run has been
> > repeated five times to circumvent the effects of standard deviation.
> > (In the odd case where baseline has -5% and patched run has +5%
> > deviation, the comparison can show ~+10% improvements which is highly
> > misleading).
> >
> > Overall, the benchmarks do not show any real difference between baseline
> > and patched kernels;
>
> Mete, thanks a lot for running the benchmarks!
>
> This confirms that we can move forward including the last patch of this series.

I also gave it a spin on a zVM instance. Results are quite similar.
FWIW, here is my tested by;

Tested-by: Mete Durlu <meted@xxxxxxxxxxxxx>