linux-kernel - Re: [PATCH] tools/power/cpupower: Fix Pstate frequency reporting on AMD Family 1Ah CPUs

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Date: Tue, 30 Apr 2024 12:06:20 -0500
From: Mario Limonciello <mario.limonciello@....com>
To: Dhananjay Ugwekar <Dhananjay.Ugwekar@....com>, trenn@...e.com,
 shuah@...nel.org
Cc: ananth.narayan@....com, gautham.shenoy@....com, linux-pm@...r.kernel.org,
 linux-kernel@...r.kernel.org, rafael@...nel.org, Perry.Yuan@....com
Subject: Re: [PATCH] tools/power/cpupower: Fix Pstate frequency reporting on
 AMD Family 1Ah CPUs

On 4/30/2024 03:37, Dhananjay Ugwekar wrote:
> Update cpupower's P-State frequency calculation and reporting with AMD
> Family 1Ah+ processors, when using the acpi-cpufreq driver. This is due
> to a change in the PStateDef MSR layout in AMD Family 1Ah+.
> 
> [ dhananjay: commit log, tested on 4th and 5th Gen AMD EPYC system ]
> 
> Signed-off-by: Ananth Narayan <Ananth.Narayan@....com>
> Signed-off-by: Dhananjay Ugwekar <Dhananjay.Ugwekar@....com>
Reviewed-by: Mario Limonciello <mario.limonciello@....com>
> ---
>   tools/power/cpupower/utils/helpers/amd.c | 26 +++++++++++++++++++++---
>   1 file changed, 23 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/power/cpupower/utils/helpers/amd.c b/tools/power/cpupower/utils/helpers/amd.c
> index c519cc89c97f..0a56e22240fc 100644
> --- a/tools/power/cpupower/utils/helpers/amd.c
> +++ b/tools/power/cpupower/utils/helpers/amd.c
> @@ -41,6 +41,16 @@ union core_pstate {
>   		unsigned res1:31;
>   		unsigned en:1;
>   	} pstatedef;
> +	/* since fam 1Ah: */
> +	struct {
> +		unsigned fid:12;
> +		unsigned res1:2;
> +		unsigned vid:8;
> +		unsigned iddval:8;
> +		unsigned idddiv:2;
> +		unsigned res2:31;
> +		unsigned en:1;
> +	} pstatedef2;
>   	unsigned long long val;
>   };
>   
> @@ -48,6 +58,10 @@ static int get_did(union core_pstate pstate)
>   {
>   	int t;
>   
> +	/* Fam 1Ah onward do not use did */
> +	if (cpupower_cpu_info.family >= 0x1A)
> +		return 0;
> +
>   	if (cpupower_cpu_info.caps & CPUPOWER_CAP_AMD_PSTATEDEF)
>   		t = pstate.pstatedef.did;
>   	else if (cpupower_cpu_info.family == 0x12)
> @@ -61,12 +75,18 @@ static int get_did(union core_pstate pstate)
>   static int get_cof(union core_pstate pstate)
>   {
>   	int t;
> -	int fid, did, cof;
> +	int fid, did, cof = 0;
>   
>   	did = get_did(pstate);
>   	if (cpupower_cpu_info.caps & CPUPOWER_CAP_AMD_PSTATEDEF) {
> -		fid = pstate.pstatedef.fid;
> -		cof = 200 * fid / did;
> +		if (cpupower_cpu_info.family >= 0x1A) {
> +			fid = pstate.pstatedef2.fid;
> +			if (fid > 0x0f)
> +				cof = (fid * 5);
> +		} else {
> +			fid = pstate.pstatedef.fid;
> +			cof = 200 * fid / did;
> +		}
>   	} else {
>   		t = 0x10;
>   		fid = pstate.pstate.fid;