Messages in this thread Patch in this message | | | From | kan.liang@linux ... | Subject | [PATCH V3 1/6] perf: Add branch stack extra | Date | Wed, 16 Aug 2023 07:36:23 -0700 |
| |
From: Kan Liang <kan.liang@linux.intel.com>
Currently, the additional information of a branch entry is stored in a u64 space. With more and more information added, the space is running out. For example, the information of occurrences of events will be added for each branch.
Add a new branch sample type, PERF_SAMPLE_BRANCH_EXTRA, to indicate whether to support an extra space.
Two places were suggested to append the extra space. https://lore.kernel.org/lkml/20230802215814.GH231007@hirez.programming.kicks-ass.net/ One place is right after the flags of each branch entry. It changes the existing struct perf_branch_entry. In the later Intel-specific implementation, two separate spaces have to be created in the struct cpu_hw_events to store different branch entry structures. That duplicates space. The other place is right after the entire struct perf_branch_stack. Only adding the new extra space in the struct cpu_hw_event is necessary. The disadvantage is that the pointer of the extra space has to be recorded. The common interface perf_sample_save_brstack() has to be updated as well.
The latter requires less space and is much straight forward. It is implemented in the patch.
Also, add a new branch sample type, PERF_SAMPLE_BRANCH_EVT_CNTRS, to indicate whether include occurrences of events in branch info. The information will be stored in the extra space.
Add two helper functions for the new branch sample types.
Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Kan Liang <kan.liang@linux.intel.com> Cc: Sandipan Das <sandipan.das@amd.com> Cc: Ravi Bangoria <ravi.bangoria@amd.com> Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com> ---
Changes since V2: - Drop the new bit in struct perf_branch_entry - Introduce a new sample type PERF_SAMPLE_BRANCH_EXTRA
arch/powerpc/perf/core-book3s.c | 2 +- arch/x86/events/amd/core.c | 2 +- arch/x86/events/core.c | 2 +- arch/x86/events/intel/core.c | 2 +- arch/x86/events/intel/ds.c | 4 ++-- include/linux/perf_event.h | 22 +++++++++++++++++++++- include/uapi/linux/perf_event.h | 9 +++++++++ kernel/events/core.c | 8 ++++++++ 8 files changed, 44 insertions(+), 7 deletions(-)
diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c index 8c1f7def596e..3c14596bbfaf 100644 --- a/arch/powerpc/perf/core-book3s.c +++ b/arch/powerpc/perf/core-book3s.c @@ -2313,7 +2313,7 @@ static void record_and_restart(struct perf_event *event, unsigned long val, struct cpu_hw_events *cpuhw; cpuhw = this_cpu_ptr(&cpu_hw_events); power_pmu_bhrb_read(event, cpuhw); - perf_sample_save_brstack(&data, event, &cpuhw->bhrb_stack); + perf_sample_save_brstack(&data, event, &cpuhw->bhrb_stack, NULL); } if (event->attr.sample_type & PERF_SAMPLE_DATA_SRC && diff --git a/arch/x86/events/amd/core.c b/arch/x86/events/amd/core.c index abadd5f23425..01c0619d12d5 100644 --- a/arch/x86/events/amd/core.c +++ b/arch/x86/events/amd/core.c @@ -930,7 +930,7 @@ static int amd_pmu_v2_handle_irq(struct pt_regs *regs) continue; if (has_branch_stack(event)) - perf_sample_save_brstack(&data, event, &cpuc->lbr_stack); + perf_sample_save_brstack(&data, event, &cpuc->lbr_stack, NULL); if (perf_event_overflow(event, &data, regs)) x86_pmu_stop(event, 0); diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index 185f902e5f28..2919bb5a53a0 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -1702,7 +1702,7 @@ int x86_pmu_handle_irq(struct pt_regs *regs) perf_sample_data_init(&data, 0, event->hw.last_period); if (has_branch_stack(event)) - perf_sample_save_brstack(&data, event, &cpuc->lbr_stack); + perf_sample_save_brstack(&data, event, &cpuc->lbr_stack, NULL); if (perf_event_overflow(event, &data, regs)) x86_pmu_stop(event, 0); diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c index 64a3533997e1..0f4ce79de4f8 100644 --- a/arch/x86/events/intel/core.c +++ b/arch/x86/events/intel/core.c @@ -3058,7 +3058,7 @@ static int handle_pmi_common(struct pt_regs *regs, u64 status) perf_sample_data_init(&data, 0, event->hw.last_period); if (has_branch_stack(event)) - perf_sample_save_brstack(&data, event, &cpuc->lbr_stack); + perf_sample_save_brstack(&data, event, &cpuc->lbr_stack, NULL); if (perf_event_overflow(event, &data, regs)) x86_pmu_stop(event, 0); diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c index eb8dd8b8a1e8..7566190389f0 100644 --- a/arch/x86/events/intel/ds.c +++ b/arch/x86/events/intel/ds.c @@ -1755,7 +1755,7 @@ static void setup_pebs_fixed_sample_data(struct perf_event *event, setup_pebs_time(event, data, pebs->tsc); if (has_branch_stack(event)) - perf_sample_save_brstack(data, event, &cpuc->lbr_stack); + perf_sample_save_brstack(data, event, &cpuc->lbr_stack, NULL); } static void adaptive_pebs_save_regs(struct pt_regs *regs, @@ -1912,7 +1912,7 @@ static void setup_pebs_adaptive_sample_data(struct perf_event *event, if (has_branch_stack(event)) { intel_pmu_store_pebs_lbrs(lbr); - perf_sample_save_brstack(data, event, &cpuc->lbr_stack); + perf_sample_save_brstack(data, event, &cpuc->lbr_stack, NULL); } } diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index e83f13ce4a9f..c4877924d43c 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -1137,6 +1137,15 @@ static inline bool branch_sample_priv(const struct perf_event *event) return event->attr.branch_sample_type & PERF_SAMPLE_BRANCH_PRIV_SAVE; } +static inline bool branch_sample_extra(const struct perf_event *event) +{ + return event->attr.branch_sample_type & PERF_SAMPLE_BRANCH_EXTRA; +} + +static inline bool branch_sample_evt_cntrs(const struct perf_event *event) +{ + return event->attr.branch_sample_type & PERF_SAMPLE_BRANCH_EVT_CNTRS; +} struct perf_sample_data { /* @@ -1171,6 +1180,7 @@ struct perf_sample_data { struct perf_callchain_entry *callchain; struct perf_raw_record *raw; struct perf_branch_stack *br_stack; + u64 *br_stack_ext; union perf_sample_weight weight; union perf_mem_data_src data_src; u64 txn; @@ -1248,7 +1258,8 @@ static inline void perf_sample_save_raw_data(struct perf_sample_data *data, static inline void perf_sample_save_brstack(struct perf_sample_data *data, struct perf_event *event, - struct perf_branch_stack *brs) + struct perf_branch_stack *brs, + u64 *brs_ext) { int size = sizeof(u64); /* nr */ @@ -1256,7 +1267,16 @@ static inline void perf_sample_save_brstack(struct perf_sample_data *data, size += sizeof(u64); size += brs->nr * sizeof(struct perf_branch_entry); + /* + * The extension space is appended after the struct perf_branch_stack. + * It is used to store the extra data of each branch, e.g., + * the occurrences of events since the last branch entry for Intel LBR. + */ + if (branch_sample_extra(event)) + size += brs->nr * sizeof(u64); + data->br_stack = brs; + data->br_stack_ext = brs_ext; data->dyn_size += size; data->sample_flags |= PERF_SAMPLE_BRANCH_STACK; } diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h index 39c6a250dd1b..252066579dae 100644 --- a/include/uapi/linux/perf_event.h +++ b/include/uapi/linux/perf_event.h @@ -204,6 +204,10 @@ enum perf_branch_sample_type_shift { PERF_SAMPLE_BRANCH_PRIV_SAVE_SHIFT = 18, /* save privilege mode */ + PERF_SAMPLE_BRANCH_EXTRA_SHIFT = 19, /* support extra space */ + + PERF_SAMPLE_BRANCH_EVT_CNTRS_SHIFT = 20, /* save occurrences of events on a branch */ + PERF_SAMPLE_BRANCH_MAX_SHIFT /* non-ABI */ }; @@ -235,6 +239,10 @@ enum perf_branch_sample_type { PERF_SAMPLE_BRANCH_PRIV_SAVE = 1U << PERF_SAMPLE_BRANCH_PRIV_SAVE_SHIFT, + PERF_SAMPLE_BRANCH_EXTRA = 1U << PERF_SAMPLE_BRANCH_EXTRA_SHIFT, + + PERF_SAMPLE_BRANCH_EVT_CNTRS = 1U << PERF_SAMPLE_BRANCH_EVT_CNTRS_SHIFT, + PERF_SAMPLE_BRANCH_MAX = 1U << PERF_SAMPLE_BRANCH_MAX_SHIFT, }; @@ -982,6 +990,7 @@ enum perf_event_type { * { u64 nr; * { u64 hw_idx; } && PERF_SAMPLE_BRANCH_HW_INDEX * { u64 from, to, flags } lbr[nr]; + * { u64 extra; } ext[nr] && PERF_SAMPLE_BRANCH_EXTRA * } && PERF_SAMPLE_BRANCH_STACK * * { u64 abi; # enum perf_sample_regs_abi diff --git a/kernel/events/core.c b/kernel/events/core.c index f84e2640ea2f..482e7efe365c 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -7324,6 +7324,14 @@ void perf_output_sample(struct perf_output_handle *handle, if (branch_sample_hw_index(event)) perf_output_put(handle, data->br_stack->hw_idx); perf_output_copy(handle, data->br_stack->entries, size); + /* + * Add the extension space which is appended + * right after the struct perf_branch_stack. + */ + if (branch_sample_extra(event) && data->br_stack_ext) { + size = data->br_stack->nr * sizeof(u64); + perf_output_copy(handle, data->br_stack_ext, size); + } } else { /* * we always store at least the value of nr -- 2.35.1
| |