Re: [PATCH 2/3] perf/x86/intel: Add a distinct name for Granite Rapids

On 2024-07-09 5:56 a.m., Peter Zijlstra wrote:

On Mon, Jul 08, 2024 at 12:33:35PM -0700, kan.liang@linux.intel.com wrote:

...

From: Kan Liang kan.liang@linux.intel.com

Currently, the Sapphire Rapids and Granite Rapids share the same PMU name, sapphire_rapids. Because from the kernel’s perspective, GNR is similar to SPR. The only key difference is that they support different extra MSRs. The code path and the PMU name are shared.

However, from end users' perspective, they are quite different. Besides the extra MSRs, GNR has a newer PEBS format, supports Retire Latency, supports new CPUID enumeration architecture, doesn't required the load-latency AUX event, has additional TMA Level 1 Architectural Events, etc. The differences can be enumerated by CPUID or the PERF_CAPABILITIES MSR. They weren't reflected in the model-specific kernel setup. But it is worth to have a distinct PMU name for GNR.

Fixes: a6742cb90b56 ("perf/x86/intel: Fix the FRONTEND encoding on GNR and MTL") Suggested-by: Ahmad Yasin ahmad.yasin@intel.com Signed-off-by: Kan Liang kan.liang@linux.intel.com Cc: stable@vger.kernel.org

---

arch/x86/events/intel/core.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c index b61367991a16..7a9f931a1f48 100644 --- a/arch/x86/events/intel/core.c +++ b/arch/x86/events/intel/core.c @@ -6943,12 +6943,17 @@ __init int intel_pmu_init(void) case INTEL_EMERALDRAPIDS_X: x86_pmu.flags |= PMU_FL_MEM_LOADS_AUX; x86_pmu.extra_regs = intel_glc_extra_regs;

• pr_cont("Sapphire Rapids events, ");
  

• name = "sapphire_rapids";
  

  fallthrough; case INTEL_GRANITERAPIDS_X: case INTEL_GRANITERAPIDS_D: intel_pmu_init_glc(NULL);

• if (!x86_pmu.extra_regs)
  

• if (!x86_pmu.extra_regs) {
  x86_pmu.extra_regs = intel_rwc_extra_regs;
  

• 	pr_cont("Granite Rapids events, ");
  

• 	name = "granite_rapids";
  

• }
  

  x86_pmu.pebs_ept = 1; x86_pmu.hw_config = hsw_hw_config; x86_pmu.get_event_constraints = glc_get_event_constraints;

@@ -6959,8 +6964,6 @@ __init int intel_pmu_init(void) td_attr = glc_td_events_attrs; tsx_attr = glc_tsx_events_attrs; intel_pmu_pebs_data_source_skl(true);

• pr_cont("Sapphire Rapids events, ");
  

• name = "sapphire_rapids";
  

  break;

For some reason this didn't want to apply cleanly (something trivial), but since I had to edit it, my fingers slipped and I ended up with the below. That ok?

Yes, the patch looks good. Thanks!

Thanks, Kan

---

Subject: perf/x86/intel: Add a distinct name for Granite Rapids From: Kan Liang kan.liang@linux.intel.com Date: Mon, 8 Jul 2024 12:33:35 -0700

From: Kan Liang kan.liang@linux.intel.com

Currently, the Sapphire Rapids and Granite Rapids share the same PMU name, sapphire_rapids. Because from the kernel’s perspective, GNR is similar to SPR. The only key difference is that they support different extra MSRs. The code path and the PMU name are shared.

However, from end users' perspective, they are quite different. Besides the extra MSRs, GNR has a newer PEBS format, supports Retire Latency, supports new CPUID enumeration architecture, doesn't required the load-latency AUX event, has additional TMA Level 1 Architectural Events, etc. The differences can be enumerated by CPUID or the PERF_CAPABILITIES MSR. They weren't reflected in the model-specific kernel setup. But it is worth to have a distinct PMU name for GNR.

Fixes: a6742cb90b56 ("perf/x86/intel: Fix the FRONTEND encoding on GNR and MTL") Suggested-by: Ahmad Yasin ahmad.yasin@intel.com Signed-off-by: Kan Liang kan.liang@linux.intel.com Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20240708193336.1192217-3-kan.liang@linux.intel.com

---

arch/x86/events/intel/core.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-)

--- a/arch/x86/events/intel/core.c +++ b/arch/x86/events/intel/core.c @@ -6788,12 +6788,18 @@ __init int intel_pmu_init(void) case INTEL_FAM6_EMERALDRAPIDS_X: x86_pmu.flags |= PMU_FL_MEM_LOADS_AUX; x86_pmu.extra_regs = intel_glc_extra_regs;

• fallthrough;
  

• pr_cont("Sapphire Rapids events, ");
  

• name = "sapphire_rapids";
  

• goto glc_common;
  

• case INTEL_FAM6_GRANITERAPIDS_X: case INTEL_FAM6_GRANITERAPIDS_D:

• x86_pmu.extra_regs = intel_rwc_extra_regs;
  

• pr_cont("Granite Rapids events, ");
  

• name = "granite_rapids";
  

• glc_common: intel_pmu_init_glc(NULL);

• if (!x86_pmu.extra_regs)
  

• 	x86_pmu.extra_regs = intel_rwc_extra_regs;
  

  x86_pmu.pebs_ept = 1; x86_pmu.hw_config = hsw_hw_config; x86_pmu.get_event_constraints = glc_get_event_constraints;

@@ -6804,8 +6810,6 @@ __init int intel_pmu_init(void) td_attr = glc_td_events_attrs; tsx_attr = glc_tsx_events_attrs; intel_pmu_pebs_data_source_skl(true);

• pr_cont("Sapphire Rapids events, ");
  

• name = "sapphire_rapids";
  

  break;

case INTEL_FAM6_ALDERLAKE: