Re: [PATCH] intel_idle: Fix C6S and C10 latency values for Pantherlake

[Artem Bityutskiy <dedekind1@gmail.com>]

Hi,

The current value are based on what I measured using wult/pbe tool.

I think it will be better to explain the problem and how this patch
fixes it, give some details about workload. And ideally, also provided
turbostat output when it runs in parallel with the workload before and
after this patch. Then we have can see CPU frequency and idle profile
of your workload with and without this patch.

Thanks!

On Tue, 2026-08-11 at 13:47 +0530, Kaushlendra Kumar wrote:
> Correct the values using BIOS ACPI _CST characterization data read from
> a Pantherlake device via
> /sys/devices/system/cpu/cpu0/cpuidle/stateN/{latency,residency}:
> 
>   C6S: exit_latency 300->127, target_residency 300->381
>   C10: exit_latency 370->1048, target_residency 2500->3144
> 
> Signed-off-by: Kaushlendra Kumar <kaushlendra.kumar@intel.com>
> ---
>  drivers/idle/intel_idle.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c
> index 651408df9c24..0b5c94c7cd3a 100644
> --- a/drivers/idle/intel_idle.c
> +++ b/drivers/idle/intel_idle.c
> @@ -1010,16 +1010,16 @@ static struct cpuidle_state ptl_cstates[] __initdata = {
>  		.name = "C6S",
>  		.desc = "MWAIT 0x21",
>  		.flags = MWAIT2flg(0x21) | CPUIDLE_FLAG_TLB_FLUSHED,
> -		.exit_latency = 300,
> -		.target_residency = 300,
> +		.exit_latency = 127,
> +		.target_residency = 381,
>  		.enter = &intel_idle,
>  		.enter_s2idle = intel_idle_s2idle, },
>  	{
>  		.name = "C10",
>  		.desc = "MWAIT 0x60",
>  		.flags = MWAIT2flg(0x60) | CPUIDLE_FLAG_TLB_FLUSHED,
> -		.exit_latency = 370,
> -		.target_residency = 2500,
> +		.exit_latency = 1048,
> +		.target_residency = 3144,
>  		.enter = &intel_idle,
>  		.enter_s2idle = intel_idle_s2idle, },
>  	{