[Patch v2 13/24] perf/x86/intel: Update dyn_constranit base on PEBS event precise level

From: Dapeng Mi
Date: Tue Feb 18 2025 - 03:19:36 EST


arch-PEBS provides CPUIDs to enumerate which counters support PEBS
sampling and precise distribution PEBS sampling. Thus PEBS constraints
should be dynamically configured base on these counter and precise
distribution bitmap instead of defining them statically.

Update event dyn_constraint base on PEBS event precise level.

Signed-off-by: Dapeng Mi <dapeng1.mi@xxxxxxxxxxxxxxx>
---
arch/x86/events/intel/core.c | 6 ++++++
arch/x86/events/intel/ds.c | 1 +
2 files changed, 7 insertions(+)

diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index 472366c3db22..c777e0531d40 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -4033,6 +4033,8 @@ static int intel_pmu_hw_config(struct perf_event *event)
return ret;

if (event->attr.precise_ip) {
+ struct arch_pebs_cap pebs_cap = hybrid(event->pmu, arch_pebs_cap);
+
if ((event->attr.config & INTEL_ARCH_EVENT_MASK) == INTEL_FIXED_VLBR_EVENT)
return -EINVAL;

@@ -4046,6 +4048,10 @@ static int intel_pmu_hw_config(struct perf_event *event)
}
if (x86_pmu.pebs_aliases)
x86_pmu.pebs_aliases(event);
+
+ if (x86_pmu.arch_pebs)
+ event->hw.dyn_constraint = event->attr.precise_ip >= 3 ?
+ pebs_cap.pdists : pebs_cap.counters;
}

if (needs_branch_stack(event)) {
diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
index 519767fc9180..615aefb4e52e 100644
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -2948,6 +2948,7 @@ static void __init intel_arch_pebs_init(void)
x86_pmu.pebs_buffer_size = PEBS_BUFFER_SIZE;
x86_pmu.drain_pebs = intel_pmu_drain_arch_pebs;
x86_pmu.pebs_capable = ~0ULL;
+ x86_pmu.flags |= PMU_FL_PEBS_ALL;

x86_pmu.pebs_enable = __intel_pmu_pebs_enable;
x86_pmu.pebs_disable = __intel_pmu_pebs_disable;
--
2.40.1