diff options
| author | Alexander Shishkin <alexander.shishkin@linux.intel.com> | 2019-08-06 11:46:01 +0300 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2019-08-28 11:29:39 +0200 |
| commit | 42880f726c66f13ae1d9ac9ce4c43abe64ecac84 (patch) | |
| tree | 24a24d94033bc9c19e1e9356467d04b47f8e668e /arch/x86/events/core.c | |
| parent | ab43762ef010967e4ccd53627f70a2eecbeafefb (diff) | |
perf/x86/intel: Support PEBS output to PT
If PEBS declares ability to output its data to Intel PT stream, use the
aux_output attribute bit to enable PEBS data output to PT. This requires
a PT event to be present and scheduled in the same context. Unlike the
DS area, the kernel does not extract PEBS records from the PT stream to
generate corresponding records in the perf stream, because that would
require real time in-kernel PT decoding, which is not feasible. The PMI,
however, can still be used.
The output setting is per-CPU, so all PEBS events must be either writing
to PT or to the DS area, therefore, in case of conflict, the conflicting
event will fail to schedule, allowing the rotation logic to alternate
between the PEBS->PT and PEBS->DS events.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: kan.liang@linux.intel.com
Link: https://lkml.kernel.org/r/20190806084606.4021-3-alexander.shishkin@linux.intel.com
Diffstat (limited to 'arch/x86/events/core.c')
| -rw-r--r-- | arch/x86/events/core.c | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index 325959d19d9a..15b90b1a8fb1 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -1005,6 +1005,27 @@ static int collect_events(struct cpu_hw_events *cpuc, struct perf_event *leader, /* current number of events already accepted */ n = cpuc->n_events; + if (!cpuc->n_events) + cpuc->pebs_output = 0; + + if (!cpuc->is_fake && leader->attr.precise_ip) { + /* + * For PEBS->PT, if !aux_event, the group leader (PT) went + * away, the group was broken down and this singleton event + * can't schedule any more. + */ + if (is_pebs_pt(leader) && !leader->aux_event) + return -EINVAL; + + /* + * pebs_output: 0: no PEBS so far, 1: PT, 2: DS + */ + if (cpuc->pebs_output && + cpuc->pebs_output != is_pebs_pt(leader) + 1) + return -EINVAL; + + cpuc->pebs_output = is_pebs_pt(leader) + 1; + } if (is_x86_event(leader)) { if (n >= max_count) @@ -2241,6 +2262,17 @@ static int x86_pmu_check_period(struct perf_event *event, u64 value) return 0; } +static int x86_pmu_aux_output_match(struct perf_event *event) +{ + if (!(pmu.capabilities & PERF_PMU_CAP_AUX_OUTPUT)) + return 0; + + if (x86_pmu.aux_output_match) + return x86_pmu.aux_output_match(event); + + return 0; +} + static struct pmu pmu = { .pmu_enable = x86_pmu_enable, .pmu_disable = x86_pmu_disable, @@ -2266,6 +2298,8 @@ static struct pmu pmu = { .sched_task = x86_pmu_sched_task, .task_ctx_size = sizeof(struct x86_perf_task_context), .check_period = x86_pmu_check_period, + + .aux_output_match = x86_pmu_aux_output_match, }; void arch_perf_update_userpage(struct perf_event *event, |