Commit 208032fe authored by Adrian Hunter's avatar Adrian Hunter Committed by Arnaldo Carvalho de Melo

perf db-export: Rename db_export__comm() to db_export__exec_comm()

Rename db_export__comm() to db_export__exec_comm() to better reflect
what it does and add explanatory comments.
Signed-off-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/20190710085810.1650-3-adrian.hunter@intel.comSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent fead24e5
......@@ -105,7 +105,13 @@ int db_export__thread(struct db_export *dbe, struct thread *thread,
return err;
}
int db_export__comm(struct db_export *dbe, struct comm *comm,
/*
* Export the "exec" comm. The "exec" comm is the program / application command
* name at the time it first executes. It is used to group threads for the same
* program. Note that the main thread pid (or thread group id tgid) cannot be
* used because it does not change when a new program is exec'ed.
*/
int db_export__exec_comm(struct db_export *dbe, struct comm *comm,
struct thread *main_thread)
{
int err;
......@@ -121,6 +127,16 @@ int db_export__comm(struct db_export *dbe, struct comm *comm,
return err;
}
/*
* Record the main thread for this comm. Note that the main thread can
* have many "exec" comms because there will be a new one every time it
* exec's. An "exec" comm however will only ever have 1 main thread.
* That is different to any other threads for that same program because
* exec() will effectively kill them, so the relationship between the
* "exec" comm and non-main threads is 1-to-1. That is why
* db_export__comm_thread() is called here for the main thread, but it
* is called for non-main threads when they are exported.
*/
return db_export__comm_thread(dbe, comm, main_thread);
}
......@@ -313,7 +329,7 @@ int db_export__sample(struct db_export *dbe, union perf_event *event,
goto out_put;
if (comm) {
err = db_export__comm(dbe, comm, main_thread);
err = db_export__exec_comm(dbe, comm, main_thread);
if (err)
goto out_put;
es.comm_db_id = comm->db_id;
......
......@@ -76,7 +76,7 @@ int db_export__evsel(struct db_export *dbe, struct perf_evsel *evsel);
int db_export__machine(struct db_export *dbe, struct machine *machine);
int db_export__thread(struct db_export *dbe, struct thread *thread,
struct machine *machine, struct comm *comm);
int db_export__comm(struct db_export *dbe, struct comm *comm,
int db_export__exec_comm(struct db_export *dbe, struct comm *comm,
struct thread *main_thread);
int db_export__comm_thread(struct db_export *dbe, struct comm *comm,
struct thread *thread);
......
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