Commit 2abfcd29 authored by Ross Zwisler's avatar Ross Zwisler Committed by Jonathan Corbet
Browse files

docs: ftrace: always use canonical ftrace path 



The canonical location for the tracefs filesystem is at /sys/kernel/tracing.

But, from Documentation/trace/ftrace.rst:

  Before 4.1, all ftrace tracing control files were within the debugfs
  file system, which is typically located at /sys/kernel/debug/tracing.
  For backward compatibility, when mounting the debugfs file system,
  the tracefs file system will be automatically mounted at:

  /sys/kernel/debug/tracing

Many parts of Documentation still reference this older debugfs path, so
let's update them to avoid confusion.

Signed-off-by: default avatarRoss Zwisler <zwisler@google.com>
Reviewed-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20230125213251.2013791-1-zwisler@google.com


Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
parent b05ada56

Documentation/admin-guide/kernel-parameters.txt

+2 −2
Original line number Diff line number Diff line
@@ -6288,7 +6288,7 @@ 
			that can be enabled or disabled just as if you were

			to echo the option name into



			    /sys/kernel/debug/tracing/trace_options

			    /sys/kernel/tracing/trace_options



			For example, to enable stacktrace option (to dump the

			stack trace of each event), add to the command line:
@@ -6321,7 +6321,7 @@ 
			[FTRACE] enable this option to disable tracing when a

			warning is hit. This turns off "tracing_on". Tracing can

			be enabled again by echoing '1' into the "tracing_on"

			file located in /sys/kernel/debug/tracing/

			file located in /sys/kernel/tracing/



			This option is useful, as it disables the trace before

			the WARNING dump is called, which prevents the trace to

Documentation/admin-guide/kernel-per-CPU-kthreads.rst

+1 −1
Original line number Diff line number Diff line
@@ -25,7 +25,7 @@ References 


-	In order to locate kernel-generated OS jitter on CPU N:



		cd /sys/kernel/debug/tracing

		cd /sys/kernel/tracing

		echo 1 > max_graph_depth # Increase the "1" for more detail

		echo function_graph > current_tracer

		# run workload

Documentation/admin-guide/pm/intel_pstate.rst

+2 −2
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@@ -712,7 +712,7 @@ it works in the `active mode <Active Mode_>`_. 
The following sequence of shell commands can be used to enable them and see

their output (if the kernel is generally configured to support event tracing)::



 # cd /sys/kernel/debug/tracing/

 # cd /sys/kernel/tracing/

 # echo 1 > events/power/pstate_sample/enable

 # echo 1 > events/power/cpu_frequency/enable

 # cat trace
@@ -732,7 +732,7 @@ The ``ftrace`` interface can be used for low-level diagnostics of 
P-state is called, the ``ftrace`` filter can be set to

:c:func:`intel_pstate_set_pstate`::



 # cd /sys/kernel/debug/tracing/

 # cd /sys/kernel/tracing/

 # cat available_filter_functions | grep -i pstate

 intel_pstate_set_pstate

 intel_pstate_cpu_init

Documentation/core-api/workqueue.rst

+2 −2
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@@ -370,8 +370,8 @@ of possible problems: 


The first one can be tracked using tracing: ::



	$ echo workqueue:workqueue_queue_work > /sys/kernel/debug/tracing/set_event

	$ cat /sys/kernel/debug/tracing/trace_pipe > out.txt

	$ echo workqueue:workqueue_queue_work > /sys/kernel/tracing/set_event

	$ cat /sys/kernel/tracing/trace_pipe > out.txt

	(wait a few secs)

	^C

Documentation/hid/intel-ish-hid.rst

+2 −2
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@@ -344,8 +344,8 @@ Documentation/ABI/testing/sysfs-bus-iio for IIO ABIs to user space. 


To debug ISH, event tracing mechanism is used. To enable debug logs::



  echo 1 > /sys/kernel/debug/tracing/events/intel_ish/enable

  cat /sys/kernel/debug/tracing/trace

  echo 1 > /sys/kernel/tracing/events/intel_ish/enable

  cat /sys/kernel/tracing/trace



3.8 ISH IIO sysfs Example on Lenovo thinkpad Yoga 260

-----------------------------------------------------