perf tools: Defer export of comms that were not 'set'

Tracing for a workload begins before the comm event is seen, which
results in the initial comm having a string of the form ":<pid>" (e.g.
":12345").

In order to export the correct string, defer the export until the new
script 'flush' callback.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
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/1414678188-14946-8-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

3 files changed, 67 insertions, 2 deletions

diff --git a/tools/perf/util/db-export.c b/tools/perf/util/db-export.c
index 017ecbb0ec05..c81dae399763 100644
--- a/tools/perf/util/db-export.c
+++ b/tools/perf/util/db-export.c
@@ -21,17 +21,74 @@
 #include "comm.h"
 #include "symbol.h"
 #include "event.h"
+#include "util.h"
 #include "thread-stack.h"
 #include "db-export.h"
 
+struct deferred_export {
+        struct list_head node;
+        struct comm *comm;
+};
+
+static int db_export__deferred(struct db_export *dbe)
+{
+        struct deferred_export *de;
+        int err;
+
+        while (!list_empty(&dbe->deferred)) {
+                de = list_entry(dbe->deferred.next, struct deferred_export,
+                                node);
+                err = dbe->export_comm(dbe, de->comm);
+                list_del(&de->node);
+                free(de);
+                if (err)
+                        return err;
+        }
+
+        return 0;
+}
+
+static void db_export__free_deferred(struct db_export *dbe)
+{
+        struct deferred_export *de;
+
+        while (!list_empty(&dbe->deferred)) {
+                de = list_entry(dbe->deferred.next, struct deferred_export,
+                                node);
+                list_del(&de->node);
+                free(de);
+        }
+}
+
+static int db_export__defer_comm(struct db_export *dbe, struct comm *comm)
+{
+        struct deferred_export *de;
+
+        de = zalloc(sizeof(struct deferred_export));
+        if (!de)
+                return -ENOMEM;
+
+        de->comm = comm;
+        list_add_tail(&de->node, &dbe->deferred);
+
+        return 0;
+}
+
 int db_export__init(struct db_export *dbe)
 {
         memset(dbe, 0, sizeof(struct db_export));
+        INIT_LIST_HEAD(&dbe->deferred);
         return 0;
 }
 
+int db_export__flush(struct db_export *dbe)
+{
+        return db_export__deferred(dbe);
+}
+
 void db_export__exit(struct db_export *dbe)
 {
+        db_export__free_deferred(dbe);
         call_return_processor__free(dbe->crp);
         dbe->crp = NULL;
 }
@@ -115,7 +172,10 @@ int db_export__comm(struct db_export *dbe, struct comm *comm,
         comm->db_id = ++dbe->comm_last_db_id;
 
         if (dbe->export_comm) {
-                err = dbe->export_comm(dbe, comm);
+                if (main_thread->comm_set)
+                        err = dbe->export_comm(dbe, comm);
+                else
+                        err = db_export__defer_comm(dbe, comm);
                 if (err)
                         return err;
         }
diff --git a/tools/perf/util/db-export.h b/tools/perf/util/db-export.h
index dd5ac2ae97d4..adbd22d66798 100644
--- a/tools/perf/util/db-export.h
+++ b/tools/perf/util/db-export.h
@@ -17,6 +17,7 @@
 #define __PERF_DB_EXPORT_H
 
 #include <linux/types.h>
+#include <linux/list.h>
 
 struct perf_evsel;
 struct machine;
@@ -74,9 +75,11 @@ struct db_export {
         u64 sample_last_db_id;
         u64 call_path_last_db_id;
         u64 call_return_last_db_id;
+        struct list_head deferred;
 };
 
 int db_export__init(struct db_export *dbe);
+int db_export__flush(struct db_export *dbe);
 void db_export__exit(struct db_export *dbe);
 int db_export__evsel(struct db_export *dbe, struct perf_evsel *evsel);
 int db_export__machine(struct db_export *dbe, struct machine *machine);
diff --git a/tools/perf/util/scripting-engines/trace-event-python.c b/tools/perf/util/scripting-engines/trace-event-python.c
index cb1d9602f418..118bc62850a8 100644
--- a/tools/perf/util/scripting-engines/trace-event-python.c
+++ b/tools/perf/util/scripting-engines/trace-event-python.c
@@ -1030,7 +1030,9 @@ error:
 
 static int python_flush_script(void)
 {
-        return 0;
+        struct tables *tables = &tables_global;
+
+        return db_export__flush(&tables->dbe);
 }
 
 /*