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From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Tom Zanussi <zanussi@kernel.org>,
	Ross Zwisler <zwisler@google.com>,
	Ching-lin Yu <chinglinyu@google.com>
Subject: [PATCH 4/6 v2] tracing/histogram: Add stacktrace type
Date: Tue, 17 Jan 2023 10:21:29 -0500	[thread overview]
Message-ID: <20230117152236.167046397@goodmis.org> (raw)
In-Reply-To: 20230117152125.268986282@goodmis.org

From: "Steven Rostedt (Google)" <rostedt@goodmis.org>

Now that stacktraces can be part of synthetic events, allow a key to be
typed as a stacktrace.

  # cd /sys/kernel/tracing
  # echo 's:block_lat u64 delta; unsigned long stack[];' >> dynamic_events
  # echo 'hist:keys=next_pid:ts=common_timestamp.usecs,st=stacktrace if prev_state == 2' >> events/sched/sched_switch/trigger
  # echo 'hist:keys=prev_pid:delta=common_timestamp.usecs-$ts,st2=$st:onmatch(sched.sched_switch).trace(block_lat,$delta,$st2)' >> events/sched/sched_switch/trigger
  # echo 'hist:keys=delta.buckets=100,stack.stacktrace:sort=delta' > events/synthetic/block_lat/trigger

  # cat events/synthetic/block_lat/hist

  # event histogram
  #
  # trigger info: hist:keys=delta.buckets=100,stacktrace:vals=hitcount:sort=delta.buckets=100:size=2048 [active]
  #

  { delta: ~ 0-99, stacktrace:
           event_hist_trigger+0x464/0x480
           event_triggers_call+0x52/0xe0
           trace_event_buffer_commit+0x193/0x250
           trace_event_raw_event_sched_switch+0xfc/0x150
           __traceiter_sched_switch+0x41/0x60
           __schedule+0x448/0x7b0
           schedule_idle+0x26/0x40
           cpu_startup_entry+0x19/0x20
           start_secondary+0xed/0xf0
           secondary_startup_64_no_verify+0xe0/0xeb
  } hitcount:          6
  { delta: ~ 0-99, stacktrace:
           event_hist_trigger+0x464/0x480
           event_triggers_call+0x52/0xe0
           trace_event_buffer_commit+0x193/0x250
           trace_event_raw_event_sched_switch+0xfc/0x150
           __traceiter_sched_switch+0x41/0x60
           __schedule+0x448/0x7b0
           schedule_idle+0x26/0x40
           cpu_startup_entry+0x19/0x20
           __pfx_kernel_init+0x0/0x10
           arch_call_rest_init+0xa/0x24
           start_kernel+0x964/0x98d
           secondary_startup_64_no_verify+0xe0/0xeb
  } hitcount:          3
  { delta: ~ 0-99, stacktrace:
           event_hist_trigger+0x464/0x480
           event_triggers_call+0x52/0xe0
           trace_event_buffer_commit+0x193/0x250
           trace_event_raw_event_sched_switch+0xfc/0x150
           __traceiter_sched_switch+0x41/0x60
           __schedule+0x448/0x7b0
           schedule+0x5a/0xb0
           worker_thread+0xaf/0x380
           kthread+0xe9/0x110
           ret_from_fork+0x2c/0x50
  } hitcount:          1
  { delta: ~ 100-199, stacktrace:
           event_hist_trigger+0x464/0x480
           event_triggers_call+0x52/0xe0
           trace_event_buffer_commit+0x193/0x250
           trace_event_raw_event_sched_switch+0xfc/0x150
           __traceiter_sched_switch+0x41/0x60
           __schedule+0x448/0x7b0
           schedule_idle+0x26/0x40
           cpu_startup_entry+0x19/0x20
           start_secondary+0xed/0xf0
           secondary_startup_64_no_verify+0xe0/0xeb
  } hitcount:         15
  [..]
  { delta: ~ 8500-8599, stacktrace:
           event_hist_trigger+0x464/0x480
           event_triggers_call+0x52/0xe0
           trace_event_buffer_commit+0x193/0x250
           trace_event_raw_event_sched_switch+0xfc/0x150
           __traceiter_sched_switch+0x41/0x60
           __schedule+0x448/0x7b0
           schedule_idle+0x26/0x40
           cpu_startup_entry+0x19/0x20
           start_secondary+0xed/0xf0
           secondary_startup_64_no_verify+0xe0/0xeb
  } hitcount:          1

  Totals:
      Hits: 89
      Entries: 11
      Dropped: 0

Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 kernel/trace/trace_events_hist.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 599c056b6048..888b7a394ce5 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -1716,6 +1716,8 @@ static const char *get_hist_field_flags(struct hist_field *hist_field)
 		flags_str = "percent";
 	else if (hist_field->flags & HIST_FIELD_FL_GRAPH)
 		flags_str = "graph";
+	else if (hist_field->flags & HIST_FIELD_FL_STACKTRACE)
+		flags_str = "stacktrace";
 
 	return flags_str;
 }
@@ -2312,6 +2314,8 @@ parse_field(struct hist_trigger_data *hist_data, struct trace_event_file *file,
 			*flags |= HIST_FIELD_FL_EXECNAME;
 		else if (strcmp(modifier, "syscall") == 0)
 			*flags |= HIST_FIELD_FL_SYSCALL;
+		else if (strcmp(modifier, "stacktrace") == 0)
+			*flags |= HIST_FIELD_FL_STACKTRACE;
 		else if (strcmp(modifier, "log2") == 0)
 			*flags |= HIST_FIELD_FL_LOG2;
 		else if (strcmp(modifier, "usecs") == 0)
-- 
2.39.0



  parent reply	other threads:[~2023-01-17 15:23 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-17 15:21 [PATCH 0/6 v2] tracing/histograms: Pass stacktrace from synthetic start event to end event Steven Rostedt
2023-01-17 15:21 ` [PATCH 1/6 v2] tracing: Simplify calculating entry size using struct_size() Steven Rostedt
2023-01-17 15:21 ` [PATCH 2/6 v2] tracing: Allow stacktraces to be saved as histogram variables Steven Rostedt
2023-01-17 15:21 ` [PATCH 3/6 v2] tracing: Allow synthetic events to pass around stacktraces Steven Rostedt
2023-01-17 15:21 ` Steven Rostedt [this message]
2023-01-17 15:21 ` [PATCH 5/6 v2] tracing/histogram: Document variable stacktrace Steven Rostedt
2023-01-17 15:21 ` [PATCH 6/6 v2] tracing/histogram: Add simple tests for stacktrace usage of synthetic events Steven Rostedt
2023-02-10 21:25 ` [PATCH 0/6 v2] tracing/histograms: Pass stacktrace from synthetic start event to end event Tom Zanussi

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