kernel/linux.git/include/uapi/linux/perf_event.h, branch v6.18.21

perf/uapi: Clean up a bit

2025-05-22T09:03:41+00:00

When applying a recent commit to the header I noticed that we have accumulated quite a bit of historic noise in this header, so do a bit of spring cleaning: - Define bitfields in a vertically aligned fashion, like perf_event_mmap_page::capabilities already does. This makes it easier to see the distribution and sizing of bits within a word, at a glance. The following is much more readable: __u64 cap_bit0 : 1, cap_bit0_is_deprecated : 1, cap_user_rdpmc : 1, cap_user_time : 1, cap_user_time_zero : 1, cap_user_time_short : 1, cap_____res : 58; Than: __u64 cap_bit0:1, cap_bit0_is_deprecated:1, cap_user_rdpmc:1, cap_user_time:1, cap_user_time_zero:1, cap_user_time_short:1, cap_____res:58; So convert all bitfield definitions from the latter style to the former style. - Fix typos and grammar - Fix capitalization - Remove whitespace noise - Harmonize the definitions of various generations and groups of PERF_MEM_ ABI values. - Vertically align all definitions and assignments to the same column (48), as the first definition (enum perf_type_id), throughout the entire header. - And in general make the code and comments to be more in sync with each other and to be more readable overall. No change in functionality. Copy the changes over to tools/include/uapi/linux/perf_event.h. Signed-off-by: Ingo Molnar Cc: Peter Zijlstra Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Alexander Shishkin Cc: Mark Rutland Cc: Namhyung Kim Cc: Ian Rogers Link: https://lore.kernel.org/r/20250521221529.2547099-1-irogers@google.com

perf/uapi: Fix PERF_RECORD_SAMPLE comments in

2025-05-22T08:01:34+00:00

AAUX data for PERF_SAMPLE_AUX appears last. PERF_SAMPLE_CGROUP is missing from the comment. This makes the comment match that in the perf_event_open man page. Signed-off-by: Ian Rogers Signed-off-by: Ingo Molnar Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: James Clark Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: linux-perf-users@vger.kernel.org Link: https://lore.kernel.org/r/20250521221529.2547099-1-irogers@google.com

perf: Extend per event callchain limit to branch stack

2025-03-17T10:23:36+00:00

The commit 97c79a38cd45 ("perf core: Per event callchain limit") introduced a per-event term to allow finer tuning of the depth of callchains to save space. It should be applied to the branch stack as well. For example, autoFDO collections require maximum LBR entries. In the meantime, other system-wide LBR users may only be interested in the latest a few number of LBRs. A per-event LBR depth would save the perf output buffer. The patch simply drops the uninterested branches, but HW still collects the maximum branches. There may be a model-specific optimization that can reduce the HW depth for some cases to reduce the overhead further. But it isn't included in the patch set. Because it's not useful for all cases. For example, ARCH LBR can utilize the PEBS and XSAVE to collect LBRs. The depth should have less impact on the collecting overhead. The model-specific optimization may be implemented later separately. Signed-off-by: Kan Liang Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20250310181536.3645382-1-kan.liang@linux.intel.com

perf/core: Add aux_pause, aux_resume, aux_start_paused

2024-11-05T11:55:43+00:00

Hardware traces, such as instruction traces, can produce a vast amount of trace data, so being able to reduce tracing to more specific circumstances can be useful. The ability to pause or resume tracing when another event happens, can do that. Add ability for an event to "pause" or "resume" AUX area tracing. Add aux_pause bit to perf_event_attr to indicate that, if the event happens, the associated AUX area tracing should be paused. Ditto aux_resume. Do not allow aux_pause and aux_resume to be set together. Add aux_start_paused bit to perf_event_attr to indicate to an AUX area event that it should start in a "paused" state. Add aux_paused to struct hw_perf_event for AUX area events to keep track of the "paused" state. aux_paused is initialized to aux_start_paused. Add PERF_EF_PAUSE and PERF_EF_RESUME modes for ->stop() and ->start() callbacks. Call as needed, during __perf_event_output(). Add aux_in_pause_resume to struct perf_buffer to prevent races with the NMI handler. Pause/resume in NMI context will miss out if it coincides with another pause/resume. To use aux_pause or aux_resume, an event must be in a group with the AUX area event as the group leader. Example (requires Intel PT and tools patches also): $ perf record --kcore -e intel_pt/aux-action=start-paused/k,syscalls:sys_enter_newuname/aux-action=resume/,syscalls:sys_exit_newuname/aux-action=pause/ uname Linux [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.043 MB perf.data ] $ perf script --call-trace uname 30805 [000] 24001.058782799: name: 0x7ffc9c1865b0 uname 30805 [000] 24001.058784424: psb offs: 0 uname 30805 [000] 24001.058784424: cbr: 39 freq: 3904 MHz (139%) uname 30805 [000] 24001.058784629: ([kernel.kallsyms]) debug_smp_processor_id uname 30805 [000] 24001.058784629: ([kernel.kallsyms]) __x64_sys_newuname uname 30805 [000] 24001.058784629: ([kernel.kallsyms]) down_read uname 30805 [000] 24001.058784629: ([kernel.kallsyms]) __cond_resched uname 30805 [000] 24001.058784629: ([kernel.kallsyms]) preempt_count_add uname 30805 [000] 24001.058784629: ([kernel.kallsyms]) in_lock_functions uname 30805 [000] 24001.058784629: ([kernel.kallsyms]) preempt_count_sub uname 30805 [000] 24001.058784629: ([kernel.kallsyms]) up_read uname 30805 [000] 24001.058784629: ([kernel.kallsyms]) preempt_count_add uname 30805 [000] 24001.058784838: ([kernel.kallsyms]) in_lock_functions uname 30805 [000] 24001.058784838: ([kernel.kallsyms]) preempt_count_sub uname 30805 [000] 24001.058784838: ([kernel.kallsyms]) _copy_to_user uname 30805 [000] 24001.058784838: ([kernel.kallsyms]) syscall_exit_to_user_mode uname 30805 [000] 24001.058784838: ([kernel.kallsyms]) syscall_exit_work uname 30805 [000] 24001.058784838: ([kernel.kallsyms]) perf_syscall_exit uname 30805 [000] 24001.058784838: ([kernel.kallsyms]) debug_smp_processor_id uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) perf_trace_buf_alloc uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) perf_swevent_get_recursion_context uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) debug_smp_processor_id uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) debug_smp_processor_id uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) perf_tp_event uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) perf_trace_buf_update uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) tracing_gen_ctx_irq_test uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) perf_swevent_event uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) __perf_event_account_interrupt uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) __this_cpu_preempt_check uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) perf_event_output_forward uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) perf_event_aux_pause uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) ring_buffer_get uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) __rcu_read_lock uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) __rcu_read_unlock uname 30805 [000] 24001.058785254: ([kernel.kallsyms]) pt_event_stop uname 30805 [000] 24001.058785254: ([kernel.kallsyms]) debug_smp_processor_id uname 30805 [000] 24001.058785254: ([kernel.kallsyms]) debug_smp_processor_id uname 30805 [000] 24001.058785254: ([kernel.kallsyms]) native_write_msr uname 30805 [000] 24001.058785463: ([kernel.kallsyms]) native_write_msr uname 30805 [000] 24001.058785639: 0x0 Signed-off-by: Adrian Hunter Signed-off-by: Peter Zijlstra (Intel) Acked-by: James Clark Link: https://lkml.kernel.org/r/20241022155920.17511-3-adrian.hunter@intel.com

perf/x86/intel: Support new data source for Lunar Lake

2024-07-04T14:00:38+00:00

A new PEBS data source format is introduced for the p-core of Lunar Lake. The data source field is extended to 8 bits with new encodings. A new layout is introduced into the union intel_x86_pebs_dse. Introduce the lnl_latency_data() to parse the new format. Enlarge the pebs_data_source[] accordingly to include new encodings. Only the mem load and the mem store events can generate the data source. Introduce INTEL_HYBRID_LDLAT_CONSTRAINT and INTEL_HYBRID_STLAT_CONSTRAINT to mark them. Add two new bits for the new cache-related data src, L2_MHB and MSC. The L2_MHB is short for L2 Miss Handling Buffer, which is similar to LFB (Line Fill Buffer), but to track the L2 Cache misses. The MSC stands for the memory-side cache. Signed-off-by: Kan Liang Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Andi Kleen Reviewed-by: Ian Rogers Link: https://lkml.kernel.org/r/20240626143545.480761-6-kan.liang@linux.intel.com

perf/x86/intel: Support branch counters logging

2023-10-27T13:05:11+00:00

The branch counters logging (A.K.A LBR event logging) introduces a per-counter indication of precise event occurrences in LBRs. It can provide a means to attribute exposed retirement latency to combinations of events across a block of instructions. It also provides a means of attributing Timed LBR latencies to events. The feature is first introduced on SRF/GRR. It is an enhancement of the ARCH LBR. It adds new fields in the LBR_INFO MSRs to log the occurrences of events on the GP counters. The information is displayed by the order of counters. The design proposed in this patch requires that the events which are logged must be in a group with the event that has LBR. If there are more than one LBR group, the counters logging information only from the current group (overflowed) are stored for the perf tool, otherwise the perf tool cannot know which and when other groups are scheduled especially when multiplexing is triggered. The user can ensure it uses the maximum number of counters that support LBR info (4 by now) by making the group large enough. The HW only logs events by the order of counters. The order may be different from the order of enabling which the perf tool can understand. When parsing the information of each branch entry, convert the counter order to the enabled order, and store the enabled order in the extension space. Unconditionally reset LBRs for an LBR event group when it's deleted. The logged counter information is only valid for the current LBR group. If another LBR group is scheduled later, the information from the stale LBRs would be otherwise wrongly interpreted. Add a sanity check in intel_pmu_hw_config(). Disable the feature if other counter filters (inv, cmask, edge, in_tx) are set or LBR call stack mode is enabled. (For the LBR call stack mode, we cannot simply flush the LBR, since it will break the call stack. Also, there is no obvious usage with the call stack mode for now.) Only applying the PERF_SAMPLE_BRANCH_COUNTERS doesn't require any branch stack setup. Expose the maximum number of supported counters and the width of the counters into the sysfs. The perf tool can use the information to parse the logged counters in each branch. Signed-off-by: Kan Liang Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20231025201626.3000228-5-kan.liang@linux.intel.com

perf: Add branch stack counters

2023-10-27T13:05:08+00:00

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. Two places were suggested to append the counters. 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. The later ARCH specific implementation has to be really careful to consistently pick the right struct. The other place is right after the entire struct perf_branch_stack. 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. The latter is much straightforward, and should be easily understood and maintained. It is implemented in the patch. Add a new branch sample type, PERF_SAMPLE_BRANCH_COUNTERS, to indicate the event which is recorded in the branch info. The "u64 counters" may store the occurrences of several events. The information regarding the number of events/counters and the width of each counter should be exposed via sysfs as a reference for the perf tool. Define the branch_counter_nr and branch_counter_width ABI here. The support will be implemented later in the Intel-specific patch. Suggested-by: Peter Zijlstra (Intel) Signed-off-by: Kan Liang Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20231025201626.3000228-1-kan.liang@linux.intel.com

perf/mem: Introduce PERF_MEM_LVLNUM_UNC

2023-07-26T10:28:44+00:00

Older API PERF_MEM_LVL_UNC can be replaced by PERF_MEM_LVLNUM_UNC. Signed-off-by: Ravi Bangoria Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20230725150206.184-2-ravi.bangoria@amd.com

perf: Add perf_event_attr::config3

2023-02-07T11:52:00+00:00

Arm SPEv1.2 adds another 64-bits of event filtering control. As the existing perf_event_attr::configN fields are all used up for SPE PMU, an additional field is needed. Add a new 'config3' field. Tested-by: James Clark Signed-off-by: Rob Herring Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20220825-arm-spe-v8-7-v4-7-327f860daf28@kernel.org Signed-off-by: Will Deacon

perf/mem: Rename PERF_MEM_LVLNUM_EXTN_MEM to PERF_MEM_LVLNUM_CXL

2022-10-27T08:27:32+00:00

PERF_MEM_LVLNUM_EXTN_MEM was introduced to cover CXL devices but it's bit ambiguous name and also not generic enough to cover cxl.cache and cxl.io devices. Rename it to PERF_MEM_LVLNUM_CXL to be more specific. Signed-off-by: Ravi Bangoria Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/f6268268-b4e9-9ed6-0453-65792644d953@amd.com