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* [PATCH] x86/events/intel/cstate: Add Pantherlake support
@ 2025-11-12  9:00 Kaushlendra Kumar
  2025-11-12 20:07 ` Dave Hansen
  2025-11-13  6:50 ` Mi, Dapeng
  0 siblings, 2 replies; 6+ messages in thread
From: Kaushlendra Kumar @ 2025-11-12  9:00 UTC (permalink / raw)
  To: mingo, acme, namhyung, jolsa, adrian.hunter, bp, dave.hansen, x86
  Cc: linux-perf-users, linux-kernel, Kaushlendra Kumar

It supports the same C-state residency counters as Lunarlake.This
enables monitoring of C1, C6, C7 core states and C2,C3,C6,C10
package states residency counters on Pantherlake platforms.

Signed-off-by: Kaushlendra Kumar <kaushlendra.kumar@intel.com>
---
 arch/x86/events/intel/cstate.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/arch/x86/events/intel/cstate.c b/arch/x86/events/intel/cstate.c
index ec753e39b007..b3582eeb6c4b 100644
--- a/arch/x86/events/intel/cstate.c
+++ b/arch/x86/events/intel/cstate.c
@@ -41,7 +41,7 @@
  *	MSR_CORE_C1_RES: CORE C1 Residency Counter
  *			 perf code: 0x00
  *			 Available model: SLM,AMT,GLM,CNL,ICX,TNT,ADL,RPL
- *					  MTL,SRF,GRR,ARL,LNL
+ *					  MTL,SRF,GRR,ARL,LNL,PTL
  *			 Scope: Core (each processor core has a MSR)
  *	MSR_CORE_C3_RESIDENCY: CORE C3 Residency Counter
  *			       perf code: 0x01
@@ -53,31 +53,32 @@
  *			       Available model: SLM,AMT,NHM,WSM,SNB,IVB,HSW,BDW,
  *						SKL,KNL,GLM,CNL,KBL,CML,ICL,ICX,
  *						TGL,TNT,RKL,ADL,RPL,SPR,MTL,SRF,
- *						GRR,ARL,LNL
+ *						GRR,ARL,LNL,PTL
  *			       Scope: Core
  *	MSR_CORE_C7_RESIDENCY: CORE C7 Residency Counter
  *			       perf code: 0x03
  *			       Available model: SNB,IVB,HSW,BDW,SKL,CNL,KBL,CML,
- *						ICL,TGL,RKL,ADL,RPL,MTL,ARL,LNL
+ *						ICL,TGL,RKL,ADL,RPL,MTL,ARL,LNL,
+ *						PTL
  *			       Scope: Core
  *	MSR_PKG_C2_RESIDENCY:  Package C2 Residency Counter.
  *			       perf code: 0x00
  *			       Available model: SNB,IVB,HSW,BDW,SKL,KNL,GLM,CNL,
  *						KBL,CML,ICL,ICX,TGL,TNT,RKL,ADL,
- *						RPL,SPR,MTL,ARL,LNL,SRF
+ *						RPL,SPR,MTL,ARL,LNL,SRF,PTL
  *			       Scope: Package (physical package)
  *	MSR_PKG_C3_RESIDENCY:  Package C3 Residency Counter.
  *			       perf code: 0x01
  *			       Available model: NHM,WSM,SNB,IVB,HSW,BDW,SKL,KNL,
  *						GLM,CNL,KBL,CML,ICL,TGL,TNT,RKL,
- *						ADL,RPL,MTL,ARL,LNL
+ *						ADL,RPL,MTL,ARL,LNL,PTL
  *			       Scope: Package (physical package)
  *	MSR_PKG_C6_RESIDENCY:  Package C6 Residency Counter.
  *			       perf code: 0x02
  *			       Available model: SLM,AMT,NHM,WSM,SNB,IVB,HSW,BDW,
  *						SKL,KNL,GLM,CNL,KBL,CML,ICL,ICX,
  *						TGL,TNT,RKL,ADL,RPL,SPR,MTL,SRF,
- *						ARL,LNL
+ *						ARL,LNL,PTL
  *			       Scope: Package (physical package)
  *	MSR_PKG_C7_RESIDENCY:  Package C7 Residency Counter.
  *			       perf code: 0x03
@@ -96,7 +97,7 @@
  *	MSR_PKG_C10_RESIDENCY: Package C10 Residency Counter.
  *			       perf code: 0x06
  *			       Available model: HSW ULT,KBL,GLM,CNL,CML,ICL,TGL,
- *						TNT,RKL,ADL,RPL,MTL,ARL,LNL
+ *						TNT,RKL,ADL,RPL,MTL,ARL,LNL,PTL
  *			       Scope: Package (physical package)
  *	MSR_MODULE_C6_RES_MS:  Module C6 Residency Counter.
  *			       perf code: 0x00
@@ -652,6 +653,7 @@ static const struct x86_cpu_id intel_cstates_match[] __initconst = {
 	X86_MATCH_VFM(INTEL_ARROWLAKE_H,	&adl_cstates),
 	X86_MATCH_VFM(INTEL_ARROWLAKE_U,	&adl_cstates),
 	X86_MATCH_VFM(INTEL_LUNARLAKE_M,	&lnl_cstates),
+	X86_MATCH_VFM(INTEL_PANTHERLAKE_L,	&lnl_cstates),
 	{ },
 };
 MODULE_DEVICE_TABLE(x86cpu, intel_cstates_match);
-- 
2.34.1


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* Re: [PATCH] x86/events/intel/cstate: Add Pantherlake support
  2025-11-12  9:00 [PATCH] x86/events/intel/cstate: Add Pantherlake support Kaushlendra Kumar
@ 2025-11-12 20:07 ` Dave Hansen
  2025-11-13  4:05   ` Kumar, Kaushlendra
  2025-11-13  6:50 ` Mi, Dapeng
  1 sibling, 1 reply; 6+ messages in thread
From: Dave Hansen @ 2025-11-12 20:07 UTC (permalink / raw)
  To: Kaushlendra Kumar, mingo, acme, namhyung, jolsa, adrian.hunter,
	bp, dave.hansen, x86
  Cc: linux-perf-users, linux-kernel

On 11/12/25 01:00, Kaushlendra Kumar wrote:
> It supports the same C-state residency counters as Lunarlake.This
> enables monitoring of C1, C6, C7 core states and C2,C3,C6,C10
> package states residency counters on Pantherlake platforms.

Is this actually documented? Or is there just a smoke-filled room at
Intel somewhere where this is decided?

> diff --git a/arch/x86/events/intel/cstate.c b/arch/x86/events/intel/cstate.c
> index ec753e39b007..b3582eeb6c4b 100644
> --- a/arch/x86/events/intel/cstate.c
> +++ b/arch/x86/events/intel/cstate.c
> @@ -41,7 +41,7 @@
>   *	MSR_CORE_C1_RES: CORE C1 Residency Counter
>   *			 perf code: 0x00
>   *			 Available model: SLM,AMT,GLM,CNL,ICX,TNT,ADL,RPL
> - *					  MTL,SRF,GRR,ARL,LNL
> + *					  MTL,SRF,GRR,ARL,LNL,PTL

Could we get rid of these, please?

Folks can 100% figure this out from the data structures themselves.
Unless there's a compelling reason, this is pure churn.

> @@ -652,6 +653,7 @@ static const struct x86_cpu_id intel_cstates_match[] __initconst = {
>  	X86_MATCH_VFM(INTEL_ARROWLAKE_H,	&adl_cstates),
>  	X86_MATCH_VFM(INTEL_ARROWLAKE_U,	&adl_cstates),
>  	X86_MATCH_VFM(INTEL_LUNARLAKE_M,	&lnl_cstates),
> +	X86_MATCH_VFM(INTEL_PANTHERLAKE_L,	&lnl_cstates),
>  	{ },
>  };
>  MODULE_DEVICE_TABLE(x86cpu, intel_cstates_match);
Also, why *can't* this just be enumerated?

^ permalink raw reply	[flat|nested] 6+ messages in thread

* RE: [PATCH] x86/events/intel/cstate: Add Pantherlake support
  2025-11-12 20:07 ` Dave Hansen
@ 2025-11-13  4:05   ` Kumar, Kaushlendra
  2025-11-13 18:20     ` Dave Hansen
  0 siblings, 1 reply; 6+ messages in thread
From: Kumar, Kaushlendra @ 2025-11-13  4:05 UTC (permalink / raw)
  To: Hansen, Dave, mingo@redhat.com, acme@kernel.org,
	namhyung@kernel.org, jolsa@kernel.org, Hunter, Adrian,
	bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org
  Cc: linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org

On 11/12/25, [Reviewer Name] wrote:
> On 11/12/25 01:00, Kaushlendra Kumar wrote:
> > It supports the same C-state residency counters as Lunarlake.This 
> > enables monitoring of C1, C6, C7 core states and C2,C3,C6,C10 package 
> > states residency counters on Pantherlake platforms.
> 
> Is this actually documented? Or is there just a smoke-filled room at 
> Intel somewhere where this is decided?

Good point. Baseline for Pantherlake is Lunarlake with respect to C states. It is documented in internal documents. This approach is consistent with similar implementations 
throughout the kernel codebase for related CPU families.

> > @@ -41,7 +41,7 @@
> >   *	MSR_CORE_C1_RES: CORE C1 Residency Counter
> >   *			 perf code: 0x00
> >   *			 Available model: SLM,AMT,GLM,CNL,ICX,TNT,ADL,RPL
> > - *					  MTL,SRF,GRR,ARL,LNL
> > + *					  MTL,SRF,GRR,ARL,LNL,PTL
> 
> Could we get rid of these, please?
> 
> Folks can 100% figure this out from the data structures themselves.
> Unless there's a compelling reason, this is pure churn.

Agreed. These comments are indeed redundant. 
If we all agree, I'll remove those.

> > @@ -652,6 +653,7 @@ static const struct x86_cpu_id intel_cstates_match[] __initconst = {
> >  	X86_MATCH_VFM(INTEL_ARROWLAKE_H,	&adl_cstates),
> >  	X86_MATCH_VFM(INTEL_ARROWLAKE_U,	&adl_cstates),
> >  	X86_MATCH_VFM(INTEL_LUNARLAKE_M,	&lnl_cstates),
> > +	X86_MATCH_VFM(INTEL_PANTHERLAKE_L,	&lnl_cstates),
> >  	{ },
> >  };
> >  MODULE_DEVICE_TABLE(x86cpu, intel_cstates_match);
> 
> Also, why *can't* this just be enumerated?

Could you clarify what you mean by "enumerated"? Are you suggesting:
1. Runtime detection instead of static matching?
2. A different approach to CPU model matching?
3. Something else?

The current approach follows the established pattern for other Intel 
CPU models in this driver. If there's a preferred alternative approach, 
I'm happy to implement it.

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] x86/events/intel/cstate: Add Pantherlake support
  2025-11-12  9:00 [PATCH] x86/events/intel/cstate: Add Pantherlake support Kaushlendra Kumar
  2025-11-12 20:07 ` Dave Hansen
@ 2025-11-13  6:50 ` Mi, Dapeng
  2025-11-13  6:59   ` Mi, Dapeng
  1 sibling, 1 reply; 6+ messages in thread
From: Mi, Dapeng @ 2025-11-13  6:50 UTC (permalink / raw)
  To: Kaushlendra Kumar, mingo, acme, namhyung, jolsa, adrian.hunter,
	bp, dave.hansen, x86
  Cc: linux-perf-users, linux-kernel

Hi Kaushlendra,

The PTL cstate enabling patch had been merged into tip perf/core branch. :)

Thanks,

- Dapeng

On 11/12/2025 5:00 PM, Kaushlendra Kumar wrote:
> It supports the same C-state residency counters as Lunarlake.This
> enables monitoring of C1, C6, C7 core states and C2,C3,C6,C10
> package states residency counters on Pantherlake platforms.
>
> Signed-off-by: Kaushlendra Kumar <kaushlendra.kumar@intel.com>
> ---
>  arch/x86/events/intel/cstate.c | 16 +++++++++-------
>  1 file changed, 9 insertions(+), 7 deletions(-)
>
> diff --git a/arch/x86/events/intel/cstate.c b/arch/x86/events/intel/cstate.c
> index ec753e39b007..b3582eeb6c4b 100644
> --- a/arch/x86/events/intel/cstate.c
> +++ b/arch/x86/events/intel/cstate.c
> @@ -41,7 +41,7 @@
>   *	MSR_CORE_C1_RES: CORE C1 Residency Counter
>   *			 perf code: 0x00
>   *			 Available model: SLM,AMT,GLM,CNL,ICX,TNT,ADL,RPL
> - *					  MTL,SRF,GRR,ARL,LNL
> + *					  MTL,SRF,GRR,ARL,LNL,PTL
>   *			 Scope: Core (each processor core has a MSR)
>   *	MSR_CORE_C3_RESIDENCY: CORE C3 Residency Counter
>   *			       perf code: 0x01
> @@ -53,31 +53,32 @@
>   *			       Available model: SLM,AMT,NHM,WSM,SNB,IVB,HSW,BDW,
>   *						SKL,KNL,GLM,CNL,KBL,CML,ICL,ICX,
>   *						TGL,TNT,RKL,ADL,RPL,SPR,MTL,SRF,
> - *						GRR,ARL,LNL
> + *						GRR,ARL,LNL,PTL
>   *			       Scope: Core
>   *	MSR_CORE_C7_RESIDENCY: CORE C7 Residency Counter
>   *			       perf code: 0x03
>   *			       Available model: SNB,IVB,HSW,BDW,SKL,CNL,KBL,CML,
> - *						ICL,TGL,RKL,ADL,RPL,MTL,ARL,LNL
> + *						ICL,TGL,RKL,ADL,RPL,MTL,ARL,LNL,
> + *						PTL
>   *			       Scope: Core
>   *	MSR_PKG_C2_RESIDENCY:  Package C2 Residency Counter.
>   *			       perf code: 0x00
>   *			       Available model: SNB,IVB,HSW,BDW,SKL,KNL,GLM,CNL,
>   *						KBL,CML,ICL,ICX,TGL,TNT,RKL,ADL,
> - *						RPL,SPR,MTL,ARL,LNL,SRF
> + *						RPL,SPR,MTL,ARL,LNL,SRF,PTL
>   *			       Scope: Package (physical package)
>   *	MSR_PKG_C3_RESIDENCY:  Package C3 Residency Counter.
>   *			       perf code: 0x01
>   *			       Available model: NHM,WSM,SNB,IVB,HSW,BDW,SKL,KNL,
>   *						GLM,CNL,KBL,CML,ICL,TGL,TNT,RKL,
> - *						ADL,RPL,MTL,ARL,LNL
> + *						ADL,RPL,MTL,ARL,LNL,PTL
>   *			       Scope: Package (physical package)
>   *	MSR_PKG_C6_RESIDENCY:  Package C6 Residency Counter.
>   *			       perf code: 0x02
>   *			       Available model: SLM,AMT,NHM,WSM,SNB,IVB,HSW,BDW,
>   *						SKL,KNL,GLM,CNL,KBL,CML,ICL,ICX,
>   *						TGL,TNT,RKL,ADL,RPL,SPR,MTL,SRF,
> - *						ARL,LNL
> + *						ARL,LNL,PTL
>   *			       Scope: Package (physical package)
>   *	MSR_PKG_C7_RESIDENCY:  Package C7 Residency Counter.
>   *			       perf code: 0x03
> @@ -96,7 +97,7 @@
>   *	MSR_PKG_C10_RESIDENCY: Package C10 Residency Counter.
>   *			       perf code: 0x06
>   *			       Available model: HSW ULT,KBL,GLM,CNL,CML,ICL,TGL,
> - *						TNT,RKL,ADL,RPL,MTL,ARL,LNL
> + *						TNT,RKL,ADL,RPL,MTL,ARL,LNL,PTL
>   *			       Scope: Package (physical package)
>   *	MSR_MODULE_C6_RES_MS:  Module C6 Residency Counter.
>   *			       perf code: 0x00
> @@ -652,6 +653,7 @@ static const struct x86_cpu_id intel_cstates_match[] __initconst = {
>  	X86_MATCH_VFM(INTEL_ARROWLAKE_H,	&adl_cstates),
>  	X86_MATCH_VFM(INTEL_ARROWLAKE_U,	&adl_cstates),
>  	X86_MATCH_VFM(INTEL_LUNARLAKE_M,	&lnl_cstates),
> +	X86_MATCH_VFM(INTEL_PANTHERLAKE_L,	&lnl_cstates),
>  	{ },
>  };
>  MODULE_DEVICE_TABLE(x86cpu, intel_cstates_match);

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] x86/events/intel/cstate: Add Pantherlake support
  2025-11-13  6:50 ` Mi, Dapeng
@ 2025-11-13  6:59   ` Mi, Dapeng
  0 siblings, 0 replies; 6+ messages in thread
From: Mi, Dapeng @ 2025-11-13  6:59 UTC (permalink / raw)
  To: Kaushlendra Kumar, mingo, acme, namhyung, jolsa, adrian.hunter,
	bp, dave.hansen, x86
  Cc: linux-perf-users, linux-kernel


On 11/13/2025 2:50 PM, Mi, Dapeng wrote:
> Hi Kaushlendra,
>
> The PTL cstate enabling patch had been merged into tip perf/core branch. :)

Sorry, forgot to paste the link.
https://lore.kernel.org/all/20251023223754.1743928-4-zide.chen@intel.com/


>
> Thanks,
>
> - Dapeng
>
> On 11/12/2025 5:00 PM, Kaushlendra Kumar wrote:
>> It supports the same C-state residency counters as Lunarlake.This
>> enables monitoring of C1, C6, C7 core states and C2,C3,C6,C10
>> package states residency counters on Pantherlake platforms.
>>
>> Signed-off-by: Kaushlendra Kumar <kaushlendra.kumar@intel.com>
>> ---
>>  arch/x86/events/intel/cstate.c | 16 +++++++++-------
>>  1 file changed, 9 insertions(+), 7 deletions(-)
>>
>> diff --git a/arch/x86/events/intel/cstate.c b/arch/x86/events/intel/cstate.c
>> index ec753e39b007..b3582eeb6c4b 100644
>> --- a/arch/x86/events/intel/cstate.c
>> +++ b/arch/x86/events/intel/cstate.c
>> @@ -41,7 +41,7 @@
>>   *	MSR_CORE_C1_RES: CORE C1 Residency Counter
>>   *			 perf code: 0x00
>>   *			 Available model: SLM,AMT,GLM,CNL,ICX,TNT,ADL,RPL
>> - *					  MTL,SRF,GRR,ARL,LNL
>> + *					  MTL,SRF,GRR,ARL,LNL,PTL
>>   *			 Scope: Core (each processor core has a MSR)
>>   *	MSR_CORE_C3_RESIDENCY: CORE C3 Residency Counter
>>   *			       perf code: 0x01
>> @@ -53,31 +53,32 @@
>>   *			       Available model: SLM,AMT,NHM,WSM,SNB,IVB,HSW,BDW,
>>   *						SKL,KNL,GLM,CNL,KBL,CML,ICL,ICX,
>>   *						TGL,TNT,RKL,ADL,RPL,SPR,MTL,SRF,
>> - *						GRR,ARL,LNL
>> + *						GRR,ARL,LNL,PTL
>>   *			       Scope: Core
>>   *	MSR_CORE_C7_RESIDENCY: CORE C7 Residency Counter
>>   *			       perf code: 0x03
>>   *			       Available model: SNB,IVB,HSW,BDW,SKL,CNL,KBL,CML,
>> - *						ICL,TGL,RKL,ADL,RPL,MTL,ARL,LNL
>> + *						ICL,TGL,RKL,ADL,RPL,MTL,ARL,LNL,
>> + *						PTL
>>   *			       Scope: Core
>>   *	MSR_PKG_C2_RESIDENCY:  Package C2 Residency Counter.
>>   *			       perf code: 0x00
>>   *			       Available model: SNB,IVB,HSW,BDW,SKL,KNL,GLM,CNL,
>>   *						KBL,CML,ICL,ICX,TGL,TNT,RKL,ADL,
>> - *						RPL,SPR,MTL,ARL,LNL,SRF
>> + *						RPL,SPR,MTL,ARL,LNL,SRF,PTL
>>   *			       Scope: Package (physical package)
>>   *	MSR_PKG_C3_RESIDENCY:  Package C3 Residency Counter.
>>   *			       perf code: 0x01
>>   *			       Available model: NHM,WSM,SNB,IVB,HSW,BDW,SKL,KNL,
>>   *						GLM,CNL,KBL,CML,ICL,TGL,TNT,RKL,
>> - *						ADL,RPL,MTL,ARL,LNL
>> + *						ADL,RPL,MTL,ARL,LNL,PTL
>>   *			       Scope: Package (physical package)
>>   *	MSR_PKG_C6_RESIDENCY:  Package C6 Residency Counter.
>>   *			       perf code: 0x02
>>   *			       Available model: SLM,AMT,NHM,WSM,SNB,IVB,HSW,BDW,
>>   *						SKL,KNL,GLM,CNL,KBL,CML,ICL,ICX,
>>   *						TGL,TNT,RKL,ADL,RPL,SPR,MTL,SRF,
>> - *						ARL,LNL
>> + *						ARL,LNL,PTL
>>   *			       Scope: Package (physical package)
>>   *	MSR_PKG_C7_RESIDENCY:  Package C7 Residency Counter.
>>   *			       perf code: 0x03
>> @@ -96,7 +97,7 @@
>>   *	MSR_PKG_C10_RESIDENCY: Package C10 Residency Counter.
>>   *			       perf code: 0x06
>>   *			       Available model: HSW ULT,KBL,GLM,CNL,CML,ICL,TGL,
>> - *						TNT,RKL,ADL,RPL,MTL,ARL,LNL
>> + *						TNT,RKL,ADL,RPL,MTL,ARL,LNL,PTL
>>   *			       Scope: Package (physical package)
>>   *	MSR_MODULE_C6_RES_MS:  Module C6 Residency Counter.
>>   *			       perf code: 0x00
>> @@ -652,6 +653,7 @@ static const struct x86_cpu_id intel_cstates_match[] __initconst = {
>>  	X86_MATCH_VFM(INTEL_ARROWLAKE_H,	&adl_cstates),
>>  	X86_MATCH_VFM(INTEL_ARROWLAKE_U,	&adl_cstates),
>>  	X86_MATCH_VFM(INTEL_LUNARLAKE_M,	&lnl_cstates),
>> +	X86_MATCH_VFM(INTEL_PANTHERLAKE_L,	&lnl_cstates),
>>  	{ },
>>  };
>>  MODULE_DEVICE_TABLE(x86cpu, intel_cstates_match);

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] x86/events/intel/cstate: Add Pantherlake support
  2025-11-13  4:05   ` Kumar, Kaushlendra
@ 2025-11-13 18:20     ` Dave Hansen
  0 siblings, 0 replies; 6+ messages in thread
From: Dave Hansen @ 2025-11-13 18:20 UTC (permalink / raw)
  To: Kumar, Kaushlendra, mingo@redhat.com, acme@kernel.org,
	namhyung@kernel.org, jolsa@kernel.org, Hunter, Adrian,
	bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org
  Cc: linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org

On 11/12/25 20:05, Kumar, Kaushlendra wrote:
> On 11/12/25, [Reviewer Name] wrote:
>> On 11/12/25 01:00, Kaushlendra Kumar wrote:
>>> It supports the same C-state residency counters as
>>> Lunarlake.This enables monitoring of C1, C6, C7 core states and
>>> C2,C3,C6,C10 package states residency counters on Pantherlake
>>> platforms.
>> 
>> Is this actually documented? Or is there just a smoke-filled room
>> at Intel somewhere where this is decided?
> 
> Good point. Baseline for Pantherlake is Lunarlake with respect to C
> states. It is documented in internal documents. This approach is
> consistent with similar implementations throughout the kernel
> codebase for related CPU families.

It needs to be publicly documented somewhere. It doesn't have to be
fancy: a web page or white paper would be fine.

I know it's been allowed to slide up until now. But, according to[1]:

	We (Intel) continuously improve, enabling us to be more curious,
	bold and innovative.

So, can we try to improve this, please?

...>> Also, why *can't* this just be enumerated?
> 
> Could you clarify what you mean by "enumerated"? Are you suggesting:
> 1. Runtime detection instead of static matching?
> 2. A different approach to CPU model matching?
> 3. Something else?
> 
> The current approach follows the established pattern for other Intel 
> CPU models in this driver. If there's a preferred alternative approach, 
> I'm happy to implement it.
Your patch effectively says:

	PTL supports C10 package states residency counters

(among others of course). Why can't there be a bit in CPUID or an MSR
somewhere that, when set, means the same thing? That way, we don't have
to keep patching the kernel every time there's a new CPU model.

I guess in general PMU things haven't been architectural. But this seems
like something that wouldn't be too hard for the CPU itself to enumerate
to software.

1.
https://www.intel.com/content/www/us/en/corporate-responsibility/our-values.html

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2025-11-13 18:20 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2025-11-12  9:00 [PATCH] x86/events/intel/cstate: Add Pantherlake support Kaushlendra Kumar
2025-11-12 20:07 ` Dave Hansen
2025-11-13  4:05   ` Kumar, Kaushlendra
2025-11-13 18:20     ` Dave Hansen
2025-11-13  6:50 ` Mi, Dapeng
2025-11-13  6:59   ` Mi, Dapeng

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