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

[Heiko Carstens <hca@linux.ibm.com>]

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.