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

[Mete Durlu <meted@linux.ibm.com>]

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@linux.ibm.com>