[PATCH RFC v3 3/4] tracing: Add support for display of tgid in trace output

From: Joel Fernandes
Date: Thu Jun 08 2017 - 22:53:58 EST


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.

Cc: kernel-team@xxxxxxxxxxx
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Tested-by: Michael Sartain <mikesart@xxxxxxxxx>
Signed-off-by: Joel Fernandes <joelaf@xxxxxxxxxx>
---
kernel/trace/trace.c | 36 ++++++++++++++++++++++--------------
kernel/trace/trace_output.c | 9 +++++++++
2 files changed, 31 insertions(+), 14 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 185a09f8b67e..8ce78f44e60d 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3325,23 +3325,29 @@ 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
@@ -3657,9 +3663,11 @@ 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 08f9bab8089e..55c743295874 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -587,6 +587,15 @@ 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);

--
2.13.0.506.g27d5fe0cd-goog