Re: [report] Performance regressions introduced via "cpuidle: menu: Remove iowait influence" on 6.12.y

[ALOK TIWARI]

Hi Christian,


On 12/3/2025 11:01 PM, ALOK TIWARI wrote:
> Hi,
>
> I’m reporting a performance regression of up to 6% sequential I/O
> vdbench regression observed on 6.12.y kernel.
> While running performance benchmarks on v6.12.60 kernel the sequential 
> I/O vdbench metrics are showing a 5-6% performance regression when 
> compared to v6.12.48
>
> Bisect root cause commit
> ========================
> - commit b39b62075ab4 ("cpuidle: menu: Remove iowait influence")
>
> Things work fine again when the previously removed performance- 
> multiplier code is added back.
>
> Test details
> ============
> The system is connected to a number of disks in disk array using 
> multipathing and directio configuration in the vdbench profile.
>
> wd=wd1,sd=sd*,rdpct=0,seekpct=sequential,xfersize=128k
> rd=128k64T,wd=wd1,iorate=max,elapsed=600,interval=1,warmup=300,threads=64
>
>
> Thanks,
> Alok

Just a gentle ping in case this was missed.
Please let us know if we are missing anything or if there are additional 
things to consider.

Thanks,
Alok