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Date: Wed, 9 Jun 2021 17:20:53 +0300 From: Adrian Hunter <adrian.hunter@...el.com> To: Peter Zijlstra <peterz@...radead.org> Cc: Ingo Molnar <mingo@...hat.com>, Arnaldo Carvalho de Melo <acme@...nel.org>, Mark Rutland <mark.rutland@....com>, Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...hat.com>, Leo Yan <leo.yan@...aro.org>, Kan Liang <kan.liang@...ux.intel.com>, x86@...nel.org, linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org Subject: [PATCH 1/3] perf/x86: Add new event for AUX output counter index PEBS-via-PT records contain a mask of applicable counters. To identify which event belongs to which counter, a side-band event is needed. Until now, there has been no side-band event, and consequently users were limited to using a single event. Add such a side-band event. Note the event is optimised to output only when the counter index changes for an event. That works only so long as all PEBS-via-PT events are scheduled together, which they are for a recording session because they are in a single group. Also no attribute bit is used to select the new event, so a new kernel is not compatible with older perf tools. The assumption being that PEBS-via-PT is sufficiently esoteric that users will not be troubled by this. Signed-off-by: Adrian Hunter <adrian.hunter@...el.com> Reviewed-by: Alexander Shishkin <alexander.shishkin@...ux.intel.com> Reviewed-by: Andi Kleen <ak@...ux.intel.com> --- arch/x86/events/core.c | 1 + arch/x86/events/intel/ds.c | 16 ++++++++++++++++ include/linux/perf_event.h | 2 ++ include/uapi/linux/perf_event.h | 15 +++++++++++++++ kernel/events/core.c | 30 ++++++++++++++++++++++++++++++ 5 files changed, 64 insertions(+) diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index 8f71dd72ef95..30d0d18eb4b6 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -660,6 +660,7 @@ static int __x86_pmu_event_init(struct perf_event *event) event->destroy = hw_perf_event_destroy; event->hw.idx = -1; + event->hw.idx_reported = -1; event->hw.last_cpu = -1; event->hw.last_tag = ~0ULL; diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c index 1ec8fd311f38..d4c149b6e82b 100644 --- a/arch/x86/events/intel/ds.c +++ b/arch/x86/events/intel/ds.c @@ -1182,6 +1182,20 @@ static void intel_pmu_pebs_via_pt_disable(struct perf_event *event) cpuc->pebs_enabled &= ~PEBS_VIA_PT_MASK; } +static void intel_pmu_report_aux_output_id(struct perf_event *event) +{ + struct hw_perf_event *hwc = &event->hw; + + /* + * So long as all PEBS-via-PT events for a recording session are + * scheduled together, then only changes to hwc->idx need be reported. + */ + if (hwc->idx != hwc->idx_reported) { + hwc->idx_reported = hwc->idx; + perf_report_aux_output_id(event, hwc->idx); + } +} + static void intel_pmu_pebs_via_pt_enable(struct perf_event *event) { struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events); @@ -1191,6 +1205,8 @@ static void intel_pmu_pebs_via_pt_enable(struct perf_event *event) if (!is_pebs_pt(event)) return; + intel_pmu_report_aux_output_id(event); + if (!(event->hw.flags & PERF_X86_EVENT_LARGE_PEBS)) cpuc->pebs_enabled |= PEBS_PMI_AFTER_EACH_RECORD; diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index f5a6a2f069ed..18bfa05537ab 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -141,6 +141,7 @@ struct hw_perf_event { unsigned long event_base; int event_base_rdpmc; int idx; + int idx_reported; int last_cpu; int flags; @@ -1397,6 +1398,7 @@ perf_event_addr_filters(struct perf_event *event) } extern void perf_event_addr_filters_sync(struct perf_event *event); +extern void perf_report_aux_output_id(struct perf_event *event, u64 hw_id); extern int perf_output_begin(struct perf_output_handle *handle, struct perf_sample_data *data, diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h index f92880a15645..c89535de1ec8 100644 --- a/include/uapi/linux/perf_event.h +++ b/include/uapi/linux/perf_event.h @@ -1141,6 +1141,21 @@ enum perf_event_type { */ PERF_RECORD_TEXT_POKE = 20, + /* + * Data written to the AUX area by hardware due to aux_output, may need + * to be matched to the event by an architecture-specific hardware ID. + * This records the hardware ID, but requires sample_id to provide the + * event ID. e.g. Intel PT uses this record to disambiguate PEBS-via-PT + * records from multiple events. + * + * struct { + * struct perf_event_header header; + * u64 hw_id; + * struct sample_id sample_id; + * }; + */ + PERF_RECORD_AUX_OUTPUT_HW_ID = 21, + PERF_RECORD_MAX, /* non-ABI */ }; diff --git a/kernel/events/core.c b/kernel/events/core.c index 6fee4a7e88d7..bf98c8932ae2 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -9055,6 +9055,36 @@ static void perf_log_itrace_start(struct perf_event *event) perf_output_end(&handle); } +void perf_report_aux_output_id(struct perf_event *event, u64 hw_id) +{ + struct perf_output_handle handle; + struct perf_sample_data sample; + struct perf_aux_event { + struct perf_event_header header; + u64 hw_id; + } rec; + int ret; + + if (event->parent) + event = event->parent; + + rec.header.type = PERF_RECORD_AUX_OUTPUT_HW_ID; + rec.header.misc = 0; + rec.header.size = sizeof(rec); + rec.hw_id = hw_id; + + perf_event_header__init_id(&rec.header, &sample, event); + ret = perf_output_begin(&handle, &sample, event, rec.header.size); + + if (ret) + return; + + perf_output_put(&handle, rec); + perf_event__output_id_sample(event, &handle, &sample); + + perf_output_end(&handle); +} + static int __perf_event_account_interrupt(struct perf_event *event, int throttle) { -- 2.17.1
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