Re: [RFC v2 PATCH 0/16] Optimize this_cpu_*() ops for non-x86 (ARM64 for this series)~

[Mete Durlu]

On 22/07/2026 01:20, Yang Shi wrote:
> S390 implemented restart sequence. Heiko didn't share too much benchmark 
> data, just confirmed there is no regression and I had a lengthy 
> discussion with him (https://lore.kernel.org/ 
> lkml/20260520092243.264847-1-hca@xxxxxxxxxxxxx/).

Hi,

regarding performance numbers from s390 and Heiko's implementation.
It is safe to say we see noticeable improvements on micro benchmarks
but nothing really pops out on regular workloads.

on 24 Cores - 48 CPUs

1. Kernel Build
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time make -j $(nproc)
~0-2% improvement - within noise ratio

2. stress-ng vm ops
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stress-ng --vm $(nproc) --vm-bytes 128M --vm-ops 100000000
~16% improvement on bogo/ops

3. stress-ng vm ops + fork
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stress-ng -M --mmapfork $(nproc) --mmapfork-bytes 128M --mmapfork-ops 10000
~6% improvement on bogo/ops

4. fork test
---------------------------------------------------------------------
stress-ng -M --fork $(nproc) --fork-ops 10000000
~13% improvement on bogo/ops

Basecommit: a2b94afeb516 ("s390/zcrypt: Replace get_zeroed_page() with 
kzalloc()")

Thanks,
-Mete Durlu