Re: [PATCH 0/3] Optimize code generation during context

Xie Yuanbin
2025-10-30T15:04:45Z

On Wed, 29 Oct 2025 11:26:39 +0100, David Hildenbrand wrote:
>> I did some testing using my devices,
>> and the testing logic is as follows:
>> ```
>> - return finish_task_switch(prev);
>> + start_time = rdtsc();
>> + barrier();
>> + rq = finish_task_switch(prev);
>> + barrier();
>> + end_time = rdtsc;
>> + return rq;
>> ```
>>
>> The test data is as follows:
>> 1. mitigations Off, without patches: 13.5 - 13.7
>> 2. mitigations Off, with patches: 13.5 - 13.7
>> 3. mitigations On, without patches: 23.3 - 23.6
>> 4. mitigations On, with patches: 16.6 - 16.8
>
> Such numbers absolutely have to be part of the relevant patches / cover
> letter to show that the compiler is not actually smart enough to make a
> good decision.

This was indeed my oversight; I did not read the submitting-patches
documentation carefully, thank you for your pointing it out, and I deeply
apologize for this.

Do I need to send the V2 version patches to supplement the relevant data?

By the way, the above data was tested in WSL. I did a more detailed test
on a physical machine. If possible, this data may be more appropriate:
Link: https://lore.kernel.org/20251027152100.62906-1-qq570070308@gmail.com

> Cheers
>
> David / dhildenb

Thanks very much.

Xie Yuanbin