perf header: Record non-CPU PMU capabilities

PMUs advertise their capabilities via sysfs attribute files but
the perf tool currently parses only core(CPU) or hybrid core PMU
capabilities. Add support of recording non-core PMU capabilities
int perf.data header.

Note that a newly proposed HEADER_PMU_CAPS is replacing existing
HEADER_HYBRID_CPU_PMU_CAPS. Special care is taken for hybrid core
PMUs by writing their capabilities first in the perf.data header
to make sure new perf.data file being read by old perf tool does
not break.

Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Ravi Bangoria <ravi.bangoria@amd.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Ananth Narayan <ananth.narayan@amd.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kim Phillips <kim.phillips@amd.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Robert Richter <rrichter@amd.com>
Cc: Sandipan Das <sandipan.das@amd.com>
Cc: Santosh Shukla <santosh.shukla@amd.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: like.xu.linux@gmail.com
Cc: x86@kernel.org
Link: https://lore.kernel.org/r/20220604044519.594-6-ravi.bangoria@amd.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 6 insertions, 4 deletions

diff --git a/tools/perf/Documentation/perf.data-file-format.txt b/tools/perf/Documentation/perf.data-file-format.txt
index bc9f0aa113d8..635ba043fd7d 100644
--- a/tools/perf/Documentation/perf.data-file-format.txt
+++ b/tools/perf/Documentation/perf.data-file-format.txt
@@ -419,18 +419,20 @@ Example:
   cpu_core cpu list : 0-15
   cpu_atom cpu list : 16-23
 
-	HEADER_HYBRID_CPU_PMU_CAPS = 31,
+	HEADER_PMU_CAPS = 31,
 
-	A list of hybrid CPU PMU capabilities.
+	List of pmu capabilities (except cpu pmu which is already
+	covered by HEADER_CPU_PMU_CAPS). Note that hybrid cpu pmu
+	capabilities are also stored here.
 
 struct {
 	u32 nr_pmu;
 	struct {
-		u32 nr_cpu_pmu_caps;
+		u32 nr_caps;
 		{
 			char	name[];
 			char	value[];
-		} [nr_cpu_pmu_caps];
+		} [nr_caps];
 		char pmu_name[];
 	} [nr_pmu];
 };