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>

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index ab9db75..c579dea 100644 (file)
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3319,23 +3319,29 @@ static void print_event_info(struct trace_buffer *buf, struct seq_file *m)
        seq_puts(m, "#\n");
 }
 
-static void print_func_help_header(struct trace_buffer *buf, struct seq_file *m)
+static void print_func_help_header(struct trace_buffer *buf, struct seq_file *m,
+                                  unsigned int flags)
 {
+       bool tgid = flags & TRACE_ITER_RECORD_TGID;
+
        print_event_info(buf, m);
-       seq_puts(m, "#           TASK-PID   CPU#      TIMESTAMP  FUNCTION\n"
-                   "#              | |       |          |         |\n");
+
+       seq_printf(m, "#           TASK-PID   CPU#   %s  TIMESTAMP  FUNCTION\n", tgid ? "TGID     " : "");
+       seq_printf(m, "#              | |       |    %s     |         |\n",      tgid ? "  |      " : "");
 }
 
-static void print_func_help_header_irq(struct trace_buffer *buf, struct seq_file *m)
+static void print_func_help_header_irq(struct trace_buffer *buf, struct seq_file *m,
+                                      unsigned int flags)
 {
-       print_event_info(buf, m);
-       seq_puts(m, "#                              _-----=> irqs-off\n"
-                   "#                             / _----=> need-resched\n"
-                   "#                            | / _---=> hardirq/softirq\n"
-                   "#                            || / _--=> preempt-depth\n"
-                   "#                            ||| /     delay\n"
-                   "#           TASK-PID   CPU#  ||||    TIMESTAMP  FUNCTION\n"
-                   "#              | |       |   ||||       |         |\n");
+       bool tgid = flags & TRACE_ITER_RECORD_TGID;
+
+       seq_printf(m, "#                          %s  _-----=> irqs-off\n",         tgid ? "          " : "");
+       seq_printf(m, "#                          %s / _----=> need-resched\n",     tgid ? "          " : "");
+       seq_printf(m, "#                          %s| / _---=> hardirq/softirq\n",  tgid ? "          " : "");
+       seq_printf(m, "#                          %s|| / _--=> preempt-depth\n",    tgid ? "          " : "");
+       seq_printf(m, "#                          %s||| /     delay\n",             tgid ? "          " : "");
+       seq_printf(m, "#           TASK-PID   CPU#%s||||    TIMESTAMP  FUNCTION\n", tgid ? "   TGID   " : "");
+       seq_printf(m, "#              | |       | %s||||       |         |\n",      tgid ? "     |    " : "");
 }
 
 void
@@ -3651,9 +3657,11 @@ void trace_default_header(struct seq_file *m)
        } else {
                if (!(trace_flags & TRACE_ITER_VERBOSE)) {
                        if (trace_flags & TRACE_ITER_IRQ_INFO)
-                               print_func_help_header_irq(iter->trace_buffer, m);
+                               print_func_help_header_irq(iter->trace_buffer,
+                                                          m, trace_flags);
                        else
-                               print_func_help_header(iter->trace_buffer, m);
+                               print_func_help_header(iter->trace_buffer, m,
+                                                      trace_flags);
                }
        }
 }

diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index 01ff999..bac629a 100644 (file)
--- 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);