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

David Hildenbrand (Arm) david at kernel.org
Tue Aug 4 23:12:18 PDT 2026


On 8/5/26 00:01, Christoph Lameter (Ampere) wrote:
> On Tue, 4 Aug 2026, David Hildenbrand (Arm) wrote:
> 
>>>
>>> You cannot accept that one instruction is faster than the same
>>> instruction prefixed with another and something else at its tail?
>>
>> I am pretty sure that you got exactly what I meant, you likely just don't have
>> the data to back it up.
>>
>> Proof me wrong!
> 
> Well you seem to have alrady seen the benchmarks that we ran and are
> running. So I had doubts on your sincerety with this comment. Seemes to be
> be just there for effect.

Let me repeat a third time:

So to be clear: claiming that the additional instructions are unacceptable I'd
expect something minimal like: "removing these 3 instructions speeds up
micro-benchmark (a, b, c) by X% and macro-benchmarks (d, e, f) by Y% compared to
Mark's approach". [1]

[1] https://lore.kernel.org/r/ea268481-d584-4744-99d6-0b05aade7d5d@kernel.org

-- 
Cheers,

David



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