Commit-ID: 073e5fca53d30ffe9e2fc637a001c78b2cdca7dd
Gitweb: http://git.kernel.org/tip/073e5fca53d30ffe9e2fc637a001c78b2cdca7dd
Author: Arnaldo Carvalho de Melo <[email protected]>
AuthorDate: Tue, 26 Apr 2016 12:33:46 -0300
Committer: Arnaldo Carvalho de Melo <[email protected]>
CommitDate: Tue, 26 Apr 2016 13:15:00 -0300
perf trace: Read thread's COMM from /proc when not set
We get notifications for threads that gets created while we're tracing,
but for preexisting threads we may end not having synthesized them, like
when tracing a 'perf trace' session that will use '--pid' to trace some
other thread.
And besides we should probably stop synthesizing those records and
instead read thread information in a lazy way, i.e. just when we need,
like done in this patch:
Now the 'pid_t' argument in 'perf_event_open' gets translated to a COMM:
# perf trace -e perf_event_open perf stat -e cycles -p 31601
0.027 ( 0.027 ms): perf/23393 perf_event_open(attr_uptr: 0x2fdd0d8, pid:
31601 (abrt-dump-journ), cpu: -1, group_fd: -1, flags: FD_CLOEXEC)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
= 3
^C
And in other syscalls containing pid_t without thread->comm_set at the
time of the formatting.
Cc: Adrian Hunter <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Milian Wolff <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
---
tools/perf/trace/beauty/pid.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/tools/perf/trace/beauty/pid.c b/tools/perf/trace/beauty/pid.c
index 111ae08..07486ea 100644
--- a/tools/perf/trace/beauty/pid.c
+++ b/tools/perf/trace/beauty/pid.c
@@ -3,9 +3,12 @@ static size_t syscall_arg__scnprintf_pid(char *bf, size_t
size, struct syscall_a
int pid = arg->val;
struct trace *trace = arg->trace;
size_t printed = scnprintf(bf, size, "%d", pid);
- struct thread *thread = machine__find_thread(trace->host, pid, pid);
+ struct thread *thread = machine__findnew_thread(trace->host, pid, pid);
if (thread != NULL) {
+ if (!thread->comm_set)
+ thread__set_comm_from_proc(thread);
+
if (thread->comm_set)
printed += scnprintf(bf + printed, size - printed,
" (%s)", thread__comm_str(thread));
