From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Changbin Du <changbin.du@gmail.com>
Subject: [for-next][PATCH 07/29] tracing/doc: Add latency tracer funcgraph example
Date: Wed, 20 Feb 2019 13:37:44 -0500 [thread overview]
Message-ID: <20190220183803.890956792@goodmis.org> (raw)
In-Reply-To: 20190220183737.034634614@goodmis.org
From: Changbin Du <changbin.du@gmail.com>
This add an example about how to use funcgraph with latency tracers.
Link: http://lkml.kernel.org/r/20190101154614.8887-6-changbin.du@gmail.com
Signed-off-by: Changbin Du <changbin.du@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
Documentation/trace/ftrace.rst | 51 ++++++++++++++++++++++++++++++++++
1 file changed, 51 insertions(+)
diff --git a/Documentation/trace/ftrace.rst b/Documentation/trace/ftrace.rst
index 0131df7f5968..6ce2763a2a3e 100644
--- a/Documentation/trace/ftrace.rst
+++ b/Documentation/trace/ftrace.rst
@@ -1396,6 +1396,57 @@ enabling function tracing, we incur an added overhead. This
overhead may extend the latency times. But nevertheless, this
trace has provided some very helpful debugging information.
+If we prefer function graph output instead of function, we can set
+display-graph option::
+ with echo 1 > options/display-graph
+
+ # tracer: irqsoff
+ #
+ # irqsoff latency trace v1.1.5 on 4.20.0-rc6+
+ # --------------------------------------------------------------------
+ # latency: 3751 us, #274/274, CPU#0 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4)
+ # -----------------
+ # | task: bash-1507 (uid:0 nice:0 policy:0 rt_prio:0)
+ # -----------------
+ # => started at: free_debug_processing
+ # => ended at: return_to_handler
+ #
+ #
+ # _-----=> irqs-off
+ # / _----=> need-resched
+ # | / _---=> hardirq/softirq
+ # || / _--=> preempt-depth
+ # ||| /
+ # REL TIME CPU TASK/PID |||| DURATION FUNCTION CALLS
+ # | | | | |||| | | | | | |
+ 0 us | 0) bash-1507 | d... | 0.000 us | _raw_spin_lock_irqsave();
+ 0 us | 0) bash-1507 | d..1 | 0.378 us | do_raw_spin_trylock();
+ 1 us | 0) bash-1507 | d..2 | | set_track() {
+ 2 us | 0) bash-1507 | d..2 | | save_stack_trace() {
+ 2 us | 0) bash-1507 | d..2 | | __save_stack_trace() {
+ 3 us | 0) bash-1507 | d..2 | | __unwind_start() {
+ 3 us | 0) bash-1507 | d..2 | | get_stack_info() {
+ 3 us | 0) bash-1507 | d..2 | 0.351 us | in_task_stack();
+ 4 us | 0) bash-1507 | d..2 | 1.107 us | }
+ [...]
+ 3750 us | 0) bash-1507 | d..1 | 0.516 us | do_raw_spin_unlock();
+ 3750 us | 0) bash-1507 | d..1 | 0.000 us | _raw_spin_unlock_irqrestore();
+ 3764 us | 0) bash-1507 | d..1 | 0.000 us | tracer_hardirqs_on();
+ bash-1507 0d..1 3792us : <stack trace>
+ => free_debug_processing
+ => __slab_free
+ => kmem_cache_free
+ => vm_area_free
+ => remove_vma
+ => exit_mmap
+ => mmput
+ => flush_old_exec
+ => load_elf_binary
+ => search_binary_handler
+ => __do_execve_file.isra.32
+ => __x64_sys_execve
+ => do_syscall_64
+ => entry_SYSCALL_64_after_hwframe
preemptoff
----------
--
2.20.1
next prev parent reply other threads:[~2019-02-20 18:39 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-20 18:37 [for-next][PATCH 00/29] tracing: Updates for 5.1 Steven Rostedt
2019-02-20 18:37 ` [for-next][PATCH 01/29] function_graph: Support displaying relative timestamp Steven Rostedt
2019-02-20 18:37 ` [for-next][PATCH 02/29] tracing: Annotate implicit fall through in parse_probe_arg() Steven Rostedt
2019-02-20 18:37 ` [for-next][PATCH 03/29] tracing: Annotate implicit fall through in predicate_parse() Steven Rostedt
2019-02-20 18:37 ` [for-next][PATCH 04/29] tracing: Add comment to predicate_parse() about "&&" or "||" Steven Rostedt
2019-02-20 18:37 ` [for-next][PATCH 05/29] tracing: Show more info for funcgraph wakeup tracers Steven Rostedt
2019-02-20 18:37 ` [for-next][PATCH 06/29] tracing: Put a margin between flags and duration for " Steven Rostedt
2019-02-20 18:37 ` Steven Rostedt [this message]
2019-02-20 18:37 ` [for-next][PATCH 08/29] tracing: Show stacktrace " Steven Rostedt
2019-02-20 18:37 ` [for-next][PATCH 09/29] ring-buffer: Remove unused function ring_buffer_page_len() Steven Rostedt
2019-02-20 18:37 ` [for-next][PATCH 10/29] tracing: Change the function format to display function names by perf Steven Rostedt
2019-02-20 18:37 ` [for-next][PATCH 11/29] ftrace: Allow enabling of filters via index of available_filter_functions Steven Rostedt
2019-02-20 18:37 ` [for-next][PATCH 12/29] uprobes: convert uprobe.ref to refcount_t Steven Rostedt
2019-02-20 18:37 ` [for-next][PATCH 13/29] tracing: No need to free iter->trace in fail path of tracing_open_pipe() Steven Rostedt
2019-02-20 18:46 ` Steven Rostedt
2019-02-20 18:50 ` Steven Rostedt
2019-02-20 18:37 ` [for-next][PATCH 14/29] tracing: Refactor hist trigger action code Steven Rostedt
2019-02-20 18:37 ` [for-next][PATCH 15/29] tracing: Make hist trigger Documentation better reflect actions/handlers Steven Rostedt
2019-02-20 18:37 ` [for-next][PATCH 16/29] tracing: Split up onmatch action data Steven Rostedt
2019-02-20 18:37 ` [for-next][PATCH 17/29] tracing: Generalize hist trigger onmax and save action Steven Rostedt
2019-02-20 18:37 ` [for-next][PATCH 18/29] tracing: Add conditional snapshot Steven Rostedt
2019-02-20 18:37 ` [for-next][PATCH 19/29] tracing: Add hist trigger snapshot() action Steven Rostedt
2019-02-20 18:37 ` [for-next][PATCH 20/29] tracing: Add hist trigger snapshot() action Documentation Steven Rostedt
2019-02-20 18:37 ` [for-next][PATCH 21/29] tracing: Add hist trigger onchange() handler Steven Rostedt
2019-02-20 18:37 ` [for-next][PATCH 22/29] tracing: Add hist trigger onchange() handler Documentation Steven Rostedt
2019-02-20 18:38 ` [for-next][PATCH 23/29] tracing: Add alternative synthetic event trace action syntax Steven Rostedt
2019-02-20 18:38 ` [for-next][PATCH 24/29] tracing: Add SPDX license GPL-2.0 license identifier to inter-event testcases Steven Rostedt
2019-02-20 18:38 ` [for-next][PATCH 25/29] tracing: Add hist trigger snapshot() action test case Steven Rostedt
2019-02-20 18:38 ` [for-next][PATCH 26/29] tracing: Add hist trigger onchange() handler " Steven Rostedt
2019-02-20 18:38 ` [for-next][PATCH 27/29] tracing: Add alternative synthetic event trace action " Steven Rostedt
2019-02-20 18:38 ` [for-next][PATCH 28/29] tracing: Add hist trigger action expected fail " Steven Rostedt
2019-02-20 18:38 ` [for-next][PATCH 29/29] tracing: Comment why cond_snapshot is checked outside of max_lock protection Steven Rostedt
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