tracing: Add support for display of tgid in trace output

Earlier patches introduced ability to record the tgid using the 'record-tgid'
option. Here we read the tgid and output it if the option is enabled.

Link: http://lkml.kernel.org/r/20170626053844.5746-3-joelaf@google.com

Cc: kernel-team@android.com
Cc: Ingo Molnar <mingo@redhat.com>
Tested-by: Michael Sartain <mikesart@gmail.com>
Signed-off-by: Joel Fernandes <joelaf@google.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

1 files changed, 9 insertions, 0 deletions

diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index 01ff99969ca7..bac629af2285 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -597,6 +597,15 @@ int trace_print_context(struct trace_iterator *iter)
         trace_seq_printf(s, "%16s-%-5d [%03d] ",
                                comm, entry->pid, iter->cpu);
 
+        if (tr->trace_flags & TRACE_ITER_RECORD_TGID) {
+                unsigned int tgid = trace_find_tgid(entry->pid);
+
+                if (!tgid)
+                        trace_seq_printf(s, "(-----) ");
+                else
+                        trace_seq_printf(s, "(%5d) ", tgid);
+        }
+
         if (tr->trace_flags & TRACE_ITER_IRQ_INFO)
                 trace_print_lat_fmt(s, entry);