Commit aa1a8ce5 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'trace-v5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace 

Pull tracing updates from Steven Rostedt:
 "New tracing features:

   - The ring buffer is no longer disabled when reading the trace file.

     The trace_pipe file was made to be used for live tracing and
     reading as it acted like the normal producer/consumer. As the trace
     file would not consume the data, the easy way of handling it was to
     just disable writes to the ring buffer.

     This came to a surprise to the BPF folks who complained about lost
     events due to reading. This is no longer an issue. If someone wants
     to keep the old disabling there's a new option "pause-on-trace"
     that can be set.

   - New set_ftrace_notrace_pid file. PIDs in this file will not be
     traced by the function tracer.

     Similar to set_ftrace_pid, which makes the function tracer only
     trace those tasks with PIDs in the file, the set_ftrace_notrace_pid
     does the reverse.

   - New set_event_notrace_pid file. PIDs in this file will cause events
     not to be traced if triggered by a task with a matching PID.

     Similar to the set_event_pid file but will not be traced. Note,
     sched_waking and sched_switch events may still be traced if one of
     the tasks referenced by those events contains a PID that is allowed
     to be traced.

  Tracing related features:

   - New bootconfig option, that is attached to the initrd file.

     If bootconfig is on the command line, then the initrd file is
     searched looking for a bootconfig appended at the end.

   - New GPU tracepoint infrastructure to help the gfx drivers to get
     off debugfs (acked by Greg Kroah-Hartman)

  And other minor updates and fixes"

* tag 'trace-v5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (27 commits)
  tracing: Do not allocate buffer in trace_find_next_entry() in atomic
  tracing: Add documentation on set_ftrace_notrace_pid and set_event_notrace_pid
  selftests/ftrace: Add test to test new set_event_notrace_pid file
  selftests/ftrace: Add test to test new set_ftrace_notrace_pid file
  tracing: Create set_event_notrace_pid to not trace tasks
  ftrace: Create set_ftrace_notrace_pid to not trace tasks
  ftrace: Make function trace pid filtering a bit more exact
  ftrace/kprobe: Show the maxactive number on kprobe_events
  tracing: Have the document reflect that the trace file keeps tracing enabled
  ring-buffer/tracing: Have iterator acknowledge dropped events
  tracing: Do not disable tracing when reading the trace file
  ring-buffer: Do not disable recording when there is an iterator
  ring-buffer: Make resize disable per cpu buffer instead of total buffer
  ring-buffer: Optimize rb_iter_head_event()
  ring-buffer: Do not die if rb_iter_peek() fails more than thrice
  ring-buffer: Have rb_iter_head_event() handle concurrent writer
  ring-buffer: Add page_stamp to iterator for synchronization
  ring-buffer: Rename ring_buffer_read() to read_buffer_iter_advance()
  ring-buffer: Have ring_buffer_empty() not depend on tracing stopped
  tracing: Save off entry when peeking at next entry
  ...
parents 4c205c84 8e99cf91

Documentation/trace/ftrace.rst

+66 −16
Original line number Diff line number Diff line
@@ -125,10 +125,13 @@ of ftrace. Here is a list of some of the key files: 
  trace:



	This file holds the output of the trace in a human

	readable format (described below). Note, tracing is temporarily

	disabled when the file is open for reading. Once all readers

	are closed, tracing is re-enabled. Opening this file for

	readable format (described below). Opening this file for

	writing with the O_TRUNC flag clears the ring buffer content.

        Note, this file is not a consumer. If tracing is off

        (no tracer running, or tracing_on is zero), it will produce

        the same output each time it is read. When tracing is on,

        it may produce inconsistent results as it tries to read

        the entire buffer without consuming it.



  trace_pipe:
@@ -142,9 +145,7 @@ of ftrace. Here is a list of some of the key files: 
	will not be read again with a sequential read. The

	"trace" file is static, and if the tracer is not

	adding more data, it will display the same

	information every time it is read. Unlike the

	"trace" file, opening this file for reading will not

	temporarily disable tracing.

	information every time it is read.



  trace_options:
@@ -262,6 +263,20 @@ of ftrace. Here is a list of some of the key files: 
	traced by the function tracer as well. This option will also

	cause PIDs of tasks that exit to be removed from the file.



  set_ftrace_notrace_pid:



        Have the function tracer ignore threads whose PID are listed in

        this file.



        If the "function-fork" option is set, then when a task whose

	PID is listed in this file forks, the child's PID will

	automatically be added to this file, and the child will not be

	traced by the function tracer as well. This option will also

	cause PIDs of tasks that exit to be removed from the file.



        If a PID is in both this file and "set_ftrace_pid", then this

        file takes precedence, and the thread will not be traced.



  set_event_pid:



	Have the events only trace a task with a PID listed in this file.
@@ -273,6 +288,19 @@ of ftrace. Here is a list of some of the key files: 
	cause the PIDs of tasks to be removed from this file when the task

	exits.



  set_event_notrace_pid:



	Have the events not trace a task with a PID listed in this file.

	Note, sched_switch and sched_wakeup will trace threads not listed

	in this file, even if a thread's PID is in the file if the

        sched_switch or sched_wakeup events also trace a thread that should

        be traced.



	To have the PIDs of children of tasks with their PID in this file

	added on fork, enable the "event-fork" option. That option will also

	cause the PIDs of tasks to be removed from this file when the task

	exits.



  set_graph_function:



	Functions listed in this file will cause the function graph
@@ -1125,6 +1153,12 @@ Here are the available options: 
	the trace displays additional information about the

	latency, as described in "Latency trace format".



  pause-on-trace

	When set, opening the trace file for read, will pause

	writing to the ring buffer (as if tracing_on was set to zero).

	This simulates the original behavior of the trace file.

	When the file is closed, tracing will be enabled again.



  record-cmd

	When any event or tracer is enabled, a hook is enabled

	in the sched_switch trace point to fill comm cache
@@ -1176,6 +1210,8 @@ Here are the available options: 
	tasks fork. Also, when tasks with PIDs in set_event_pid exit,

	their PIDs will be removed from the file.



        This affects PIDs listed in set_event_notrace_pid as well.



  function-trace

	The latency tracers will enable function tracing

	if this option is enabled (default it is). When
@@ -1190,6 +1226,8 @@ Here are the available options: 
	set_ftrace_pid exit, their PIDs will be removed from the

	file.



        This affects PIDs in set_ftrace_notrace_pid as well.



  display-graph

	When set, the latency tracers (irqsoff, wakeup, etc) will

	use function graph tracing instead of function tracing.
@@ -2126,6 +2164,8 @@ periodically make a CPU constantly busy with interrupts disabled. 
  # cat trace

  # tracer: hwlat

  #

  # entries-in-buffer/entries-written: 13/13   #P:8

  #

  #                              _-----=> irqs-off

  #                             / _----=> need-resched

  #                            | / _---=> hardirq/softirq
@@ -2133,12 +2173,18 @@ periodically make a CPU constantly busy with interrupts disabled. 
  #                            ||| /     delay

  #           TASK-PID   CPU#  ||||    TIMESTAMP  FUNCTION

  #              | |       |   ||||       |         |

             <...>-3638  [001] d... 19452.055471: #1     inner/outer(us):   12/14    ts:1499801089.066141940

             <...>-3638  [003] d... 19454.071354: #2     inner/outer(us):   11/9     ts:1499801091.082164365

             <...>-3638  [002] dn.. 19461.126852: #3     inner/outer(us):   12/9     ts:1499801098.138150062

             <...>-3638  [001] d... 19488.340960: #4     inner/outer(us):    8/12    ts:1499801125.354139633

             <...>-3638  [003] d... 19494.388553: #5     inner/outer(us):    8/12    ts:1499801131.402150961

             <...>-3638  [003] d... 19501.283419: #6     inner/outer(us):    0/12    ts:1499801138.297435289 nmi-total:4 nmi-count:1

             <...>-1729  [001] d...   678.473449: #1     inner/outer(us):   11/12    ts:1581527483.343962693 count:6

             <...>-1729  [004] d...   689.556542: #2     inner/outer(us):   16/9     ts:1581527494.889008092 count:1

             <...>-1729  [005] d...   714.756290: #3     inner/outer(us):   16/16    ts:1581527519.678961629 count:5

             <...>-1729  [001] d...   718.788247: #4     inner/outer(us):    9/17    ts:1581527523.889012713 count:1

             <...>-1729  [002] d...   719.796341: #5     inner/outer(us):   13/9     ts:1581527524.912872606 count:1

             <...>-1729  [006] d...   844.787091: #6     inner/outer(us):    9/12    ts:1581527649.889048502 count:2

             <...>-1729  [003] d...   849.827033: #7     inner/outer(us):   18/9     ts:1581527654.889013793 count:1

             <...>-1729  [007] d...   853.859002: #8     inner/outer(us):    9/12    ts:1581527658.889065736 count:1

             <...>-1729  [001] d...   855.874978: #9     inner/outer(us):    9/11    ts:1581527660.861991877 count:1

             <...>-1729  [001] d...   863.938932: #10    inner/outer(us):    9/11    ts:1581527668.970010500 count:1 nmi-total:7 nmi-count:1

             <...>-1729  [007] d...   878.050780: #11    inner/outer(us):    9/12    ts:1581527683.385002600 count:1 nmi-total:5 nmi-count:1

             <...>-1729  [007] d...   886.114702: #12    inner/outer(us):    9/12    ts:1581527691.385001600 count:1





The above output is somewhat the same in the header. All events will have
@@ -2148,7 +2194,7 @@ interrupts disabled 'd'. Under the FUNCTION title there is: 
	This is the count of events recorded that were greater than the

	tracing_threshold (See below).



 inner/outer(us):   12/14

 inner/outer(us):   11/11



      This shows two numbers as "inner latency" and "outer latency". The test

      runs in a loop checking a timestamp twice. The latency detected within
@@ -2156,11 +2202,15 @@ interrupts disabled 'd'. Under the FUNCTION title there is: 
      after the previous timestamp and the next timestamp in the loop is

      the "outer latency".



 ts:1499801089.066141940

 ts:1581527483.343962693



      The absolute timestamp that the first latency was recorded in the window.



 count:6



      The absolute timestamp that the event happened.

      The number of times a latency was detected during the window.



 nmi-total:4 nmi-count:1

 nmi-total:7 nmi-count:1



      On architectures that support it, if an NMI comes in during the

      test, the time spent in NMI is reported in "nmi-total" (in

drivers/Kconfig

+2 −0
Original line number Diff line number Diff line
@@ -200,6 +200,8 @@ source "drivers/thunderbolt/Kconfig" 


source "drivers/android/Kconfig"



source "drivers/gpu/trace/Kconfig"



source "drivers/nvdimm/Kconfig"



source "drivers/dax/Kconfig"

drivers/gpu/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -5,3 +5,4 @@ 
obj-$(CONFIG_TEGRA_HOST1X)	+= host1x/

obj-y			+= drm/ vga/

obj-$(CONFIG_IMX_IPUV3_CORE)	+= ipu-v3/

obj-$(CONFIG_TRACE_GPU_MEM)		+= trace/

drivers/gpu/trace/Kconfig

0 → 100644
+4 −0
Original line number Diff line number Diff line 
# SPDX-License-Identifier: GPL-2.0-only



config TRACE_GPU_MEM

	bool

drivers/gpu/trace/Makefile

0 → 100644
+3 −0
Original line number Diff line number Diff line 
# SPDX-License-Identifier: GPL-2.0



obj-$(CONFIG_TRACE_GPU_MEM) += trace_gpu_mem.o

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