linux-kernel - Re: [PATCH 3/4] perf/x86/intel: Support hybrid PMU with multiple atom uarchs

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Message-ID: <20240810215539.GG11646@noisy.programming.kicks-ass.net>
Date: Sat, 10 Aug 2024 23:55:39 +0200
From: Peter Zijlstra <peterz@...radead.org>
To: Dapeng Mi <dapeng1.mi@...ux.intel.com>
Cc: Ingo Molnar <mingo@...hat.com>,
	Arnaldo Carvalho de Melo <acme@...nel.org>,
	Namhyung Kim <namhyung@...nel.org>, Ian Rogers <irogers@...gle.com>,
	Adrian Hunter <adrian.hunter@...el.com>,
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	Kan Liang <kan.liang@...ux.intel.com>, linux-kernel@...r.kernel.org,
	Andi Kleen <ak@...ux.intel.com>,
	Zhenyu Wang <zhenyuw@...ux.intel.com>,
	Yongwei Ma <yongwei.ma@...el.com>,
	Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>,
	Dapeng Mi <dapeng1.mi@...el.com>
Subject: Re: [PATCH 3/4] perf/x86/intel: Support hybrid PMU with multiple
 atom uarchs

On Thu, Aug 08, 2024 at 02:02:09PM +0000, Dapeng Mi wrote:
>  arch/x86/events/intel/core.c | 24 +++++++++++++++++-------
>  arch/x86/events/perf_event.h | 18 +++++++++++++++++-
>  2 files changed, 34 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
> index 0c9c2706d4ec..b6429bc009c0 100644
> --- a/arch/x86/events/intel/core.c
> +++ b/arch/x86/events/intel/core.c

> @@ -6218,6 +6227,7 @@ static inline int intel_pmu_v6_addr_offset(int index, bool eventsel)
>  static const struct { enum hybrid_pmu_type id; char *name; } intel_hybrid_pmu_type_map[] __initconst = {
>  	{ hybrid_small, "cpu_atom" },
>  	{ hybrid_big, "cpu_core" },
> +	{ hybrid_small2, "cpu_atom2" },

This is awfully uninspired and quite terrible. How is one supposed to
know which is which? A possibly better naming might be: hybrid_tiny,
"cpu_lowpower" or whatever.

>  };
>  
>  static __always_inline int intel_pmu_init_hybrid(enum hybrid_pmu_type pmus)
> @@ -6250,7 +6260,7 @@ static __always_inline int intel_pmu_init_hybrid(enum hybrid_pmu_type pmus)
>  							0, x86_pmu_num_counters(&pmu->pmu), 0, 0);
>  
>  		pmu->intel_cap.capabilities = x86_pmu.intel_cap.capabilities;
> -		if (pmu->pmu_type & hybrid_small) {
> +		if (pmu->pmu_type & hybrid_small_all) {
>  			pmu->intel_cap.perf_metrics = 0;
>  			pmu->intel_cap.pebs_output_pt_available = 1;
>  			pmu->mid_ack = true;
> diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
> index 5d1677844e04..f7b55c909eff 100644
> --- a/arch/x86/events/perf_event.h
> +++ b/arch/x86/events/perf_event.h
> @@ -668,6 +668,13 @@ enum {
>  #define PERF_PEBS_DATA_SOURCE_GRT_MAX	0x10
>  #define PERF_PEBS_DATA_SOURCE_GRT_MASK	(PERF_PEBS_DATA_SOURCE_GRT_MAX - 1)
>  
> +
> +/*
> + * CPUID.1AH.EAX[31:0] uniquely identifies the microarchitecture
> + * of the core. Bits 31-24 indicates its core type (Core or Atom)
> + * and Bits [23:0] indicates the native model ID of the core.
> + * Core type and native model ID are defined in below enumerations.
> + */
>  enum hybrid_cpu_type {
>  	HYBRID_INTEL_NONE,
>  	HYBRID_INTEL_ATOM	= 0x20,
> @@ -676,12 +683,21 @@ enum hybrid_cpu_type {
>  
>  #define X86_HYBRID_PMU_ATOM_IDX		0
>  #define X86_HYBRID_PMU_CORE_IDX		1
> +#define X86_HYBRID_PMU_ATOM2_IDX	2
>  enum hybrid_pmu_type {
>  	not_hybrid,
>  	hybrid_small		= BIT(X86_HYBRID_PMU_ATOM_IDX),
>  	hybrid_big		= BIT(X86_HYBRID_PMU_CORE_IDX),
> +	hybrid_small2		= BIT(X86_HYBRID_PMU_ATOM2_IDX),
> +	/* The belows are only used for matching */
> +	hybrid_big_small	= hybrid_big | hybrid_small,
> +	hybrid_small_all	= hybrid_small | hybrid_small2,
> +	hybrid_big_small_arl_h	= hybrid_big | hybrid_small_all,

Same complaint, how about:

+	hybrid_tiny		= BIT(X86_HYBRID_PMU_TINY_IDX),
	hybrid_big_small	= hybrid_big | hybrid_small,
+	hybrid_small_tiny	= hybrid_small | hybrid_tiny,
+	hybrid_big_small_tiny	= hybrid_big_small | hybrid_tiny,


> +};
>  
> -	hybrid_big_small	= hybrid_big | hybrid_small, /* only used for matching */
> +enum atom_native_id {
> +	cmt_native_id           = 0x2,  /* Crestmont */
> +	skt_native_id           = 0x3,  /* Skymont */
>  };
>  
>  struct x86_hybrid_pmu {
> -- 
> 2.40.1
>