perf tools: Add id index

Add an index of the event identifiers, in preparation for Intel PT.

The event id (also called the sample id) is a unique number
allocated by the kernel to the event created by perf_event_open().  Events
can include the event id by having a sample type including PERF_SAMPLE_ID or
PERF_SAMPLE_IDENTIFIER.

Currently the main use of the event id is to match an event back to the
evsel to which it belongs i.e. perf_evlist__id2evsel()

The purpose of this patch is to make it possible to match an event back to
the mmap from which it was read.  The reason that is useful is because the
mmap represents a time-ordered context (either for a cpu or for a thread).
Intel PT decodes trace information on that basis.  In full-trace mode, that
information can be recorded when the Intel PT trace is read, but in
sample-mode the Intel PT trace data is embedded in a sample and it is in
that case that the "id index" is needed.

So the mmaps are numbered (idx) and the cpu and tid recorded against the id
by perf_evlist__set_sid_idx() which is called by perf_evlist__mmap_per_evsel().

That information is recorded on the perf.data file in the new "id index".
idx, cpu and tid are added to struct perf_sample_id (which is the node of
evlist's hash table to match ids to evsels).  The information can be
retrieved using perf_evlist__id2sid().  Note however this all depends on
having a sample type including PERF_SAMPLE_ID or PERF_SAMPLE_IDENTIFIER,
otherwise ids are not recorded.

The "id index" is a synthesized event record which will be created when
Intel PT sampling is used by calling perf_event__synthesize_id_index().

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1414417770-18602-2-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 122 insertions, 0 deletions

diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 776010844cdc..27a0049118b5 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -228,6 +228,15 @@ static int process_finished_round(struct perf_tool *tool,
 				  union perf_event *event,
 				  struct perf_session *session);
 
+static int process_id_index_stub(struct perf_tool *tool __maybe_unused,
+				 union perf_event *event __maybe_unused,
+				 struct perf_session *perf_session
+				 __maybe_unused)
+{
+	dump_printf(": unhandled!\n");
+	return 0;
+}
+
 void perf_tool__fill_defaults(struct perf_tool *tool)
 {
 	if (tool->sample == NULL)
@@ -262,6 +271,8 @@ void perf_tool__fill_defaults(struct perf_tool *tool)
 		else
 			tool->finished_round = process_finished_round_stub;
 	}
+	if (tool->id_index == NULL)
+		tool->id_index = process_id_index_stub;
 }
  
 static void swap_sample_id_all(union perf_event *event, void *data)
@@ -460,6 +471,7 @@ static perf_event__swap_op perf_event__swap_ops[] = {
 	[PERF_RECORD_HEADER_EVENT_TYPE]	  = perf_event__event_type_swap,
 	[PERF_RECORD_HEADER_TRACING_DATA] = perf_event__tracing_data_swap,
 	[PERF_RECORD_HEADER_BUILD_ID]	  = NULL,
+	[PERF_RECORD_ID_INDEX]		  = perf_event__all64_swap,
 	[PERF_RECORD_HEADER_MAX]	  = NULL,
 };
 
@@ -888,6 +900,8 @@ static s64 perf_session__process_user_event(struct perf_session *session,
 		return tool->build_id(tool, event, session);
 	case PERF_RECORD_FINISHED_ROUND:
 		return tool->finished_round(tool, event, session);
+	case PERF_RECORD_ID_INDEX:
+		return tool->id_index(tool, event, session);
 	default:
 		return -EINVAL;
 	}
@@ -1594,3 +1608,111 @@ int __perf_session__set_tracepoints_handlers(struct perf_session *session,
 out:
 	return err;
 }
+
+int perf_event__process_id_index(struct perf_tool *tool __maybe_unused,
+				 union perf_event *event,
+				 struct perf_session *session)
+{
+	struct perf_evlist *evlist = session->evlist;
+	struct id_index_event *ie = &event->id_index;
+	size_t i, nr, max_nr;
+
+	max_nr = (ie->header.size - sizeof(struct id_index_event)) /
+		 sizeof(struct id_index_entry);
+	nr = ie->nr;
+	if (nr > max_nr)
+		return -EINVAL;
+
+	if (dump_trace)
+		fprintf(stdout, " nr: %zu\n", nr);
+
+	for (i = 0; i < nr; i++) {
+		struct id_index_entry *e = &ie->entries[i];
+		struct perf_sample_id *sid;
+
+		if (dump_trace) {
+			fprintf(stdout,	" ... id: %"PRIu64, e->id);
+			fprintf(stdout,	"  idx: %"PRIu64, e->idx);
+			fprintf(stdout,	"  cpu: %"PRId64, e->cpu);
+			fprintf(stdout,	"  tid: %"PRId64"\n", e->tid);
+		}
+
+		sid = perf_evlist__id2sid(evlist, e->id);
+		if (!sid)
+			return -ENOENT;
+		sid->idx = e->idx;
+		sid->cpu = e->cpu;
+		sid->tid = e->tid;
+	}
+	return 0;
+}
+
+int perf_event__synthesize_id_index(struct perf_tool *tool,
+				    perf_event__handler_t process,
+				    struct perf_evlist *evlist,
+				    struct machine *machine)
+{
+	union perf_event *ev;
+	struct perf_evsel *evsel;
+	size_t nr = 0, i = 0, sz, max_nr, n;
+	int err;
+
+	pr_debug2("Synthesizing id index\n");
+
+	max_nr = (UINT16_MAX - sizeof(struct id_index_event)) /
+		 sizeof(struct id_index_entry);
+
+	list_for_each_entry(evsel, &evlist->entries, node)
+		nr += evsel->ids;
+
+	n = nr > max_nr ? max_nr : nr;
+	sz = sizeof(struct id_index_event) + n * sizeof(struct id_index_entry);
+	ev = zalloc(sz);
+	if (!ev)
+		return -ENOMEM;
+
+	ev->id_index.header.type = PERF_RECORD_ID_INDEX;
+	ev->id_index.header.size = sz;
+	ev->id_index.nr = n;
+
+	list_for_each_entry(evsel, &evlist->entries, node) {
+		u32 j;
+
+		for (j = 0; j < evsel->ids; j++) {
+			struct id_index_entry *e;
+			struct perf_sample_id *sid;
+
+			if (i >= n) {
+				err = process(tool, ev, NULL, machine);
+				if (err)
+					goto out_err;
+				nr -= n;
+				i = 0;
+			}
+
+			e = &ev->id_index.entries[i++];
+
+			e->id = evsel->id[j];
+
+			sid = perf_evlist__id2sid(evlist, e->id);
+			if (!sid) {
+				free(ev);
+				return -ENOENT;
+			}
+
+			e->idx = sid->idx;
+			e->cpu = sid->cpu;
+			e->tid = sid->tid;
+		}
+	}
+
+	sz = sizeof(struct id_index_event) + nr * sizeof(struct id_index_entry);
+	ev->id_index.header.size = sz;
+	ev->id_index.nr = nr;
+
+	err = process(tool, ev, NULL, machine);
+out_err:
+	free(ev);
+
+	return err;
+}