Commit d8f0ae3e authored by Tom Zanussi's avatar Tom Zanussi Committed by Steven Rostedt (Google)
Browse files

tracing/histogram: Fix stacktrace histogram Documententation 

Fix a small problem with the histogram specification in the
Documentation, and change the example to show output using a
stacktrace field rather than the global stacktrace.

Link: https://lkml.kernel.org/r/f75f807dd4998249e513515f703a2ff7407605f4.1676063532.git.zanussi@kernel.org



Signed-off-by: default avatarTom Zanussi <zanussi@kernel.org>
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent f5914b30

Documentation/trace/histogram.rst

+90 −66
Original line number Diff line number Diff line
@@ -1993,81 +1993,105 @@ uninterruptible state:: 
A synthetic event that has a stacktrace field may use it as a key in

histogram::



  # echo 'hist:delta.buckets=100,stack.stacktrace:sort=delta' > events/synthetic/block_lat/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]

  # trigger info: hist:keys=delta.buckets=100,stack.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

  { delta: ~ 0-99, stack.stacktrace         __schedule+0xa19/0x1520

         schedule+0x6b/0x110

         io_schedule+0x46/0x80

         bit_wait_io+0x11/0x80

         __wait_on_bit+0x4e/0x120

         out_of_line_wait_on_bit+0x8d/0xb0

         __wait_on_buffer+0x33/0x40

         jbd2_journal_commit_transaction+0x155a/0x19b0

         kjournald2+0xab/0x270

         kthread+0xfa/0x130

         ret_from_fork+0x29/0x50

  } hitcount:          1

  { delta: ~ 0-99, stack.stacktrace         __schedule+0xa19/0x1520

         schedule+0x6b/0x110

         io_schedule+0x46/0x80

         rq_qos_wait+0xd0/0x170

         wbt_wait+0x9e/0xf0

         __rq_qos_throttle+0x25/0x40

         blk_mq_submit_bio+0x2c3/0x5b0

         __submit_bio+0xff/0x190

         submit_bio_noacct_nocheck+0x25b/0x2b0

         submit_bio_noacct+0x20b/0x600

         submit_bio+0x28/0x90

         ext4_bio_write_page+0x1e0/0x8c0

         mpage_submit_page+0x60/0x80

         mpage_process_page_bufs+0x16c/0x180

         mpage_prepare_extent_to_map+0x23f/0x530

  } hitcount:          1

  { delta: ~ 0-99, stack.stacktrace         __schedule+0xa19/0x1520

         schedule+0x6b/0x110

         schedule_hrtimeout_range_clock+0x97/0x110

         schedule_hrtimeout_range+0x13/0x20

         usleep_range_state+0x65/0x90

         __intel_wait_for_register+0x1c1/0x230 [i915]

         intel_psr_wait_for_idle_locked+0x171/0x2a0 [i915]

         intel_pipe_update_start+0x169/0x360 [i915]

         intel_update_crtc+0x112/0x490 [i915]

         skl_commit_modeset_enables+0x199/0x600 [i915]

         intel_atomic_commit_tail+0x7c4/0x1080 [i915]

         intel_atomic_commit_work+0x12/0x20 [i915]

         process_one_work+0x21c/0x3f0

         worker_thread+0x50/0x3e0

         kthread+0xfa/0x130

  } 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

  { delta: ~ 0-99, stack.stacktrace         __schedule+0xa19/0x1520

         schedule+0x6b/0x110

         schedule_timeout+0x11e/0x160

         __wait_for_common+0x8f/0x190

         wait_for_completion+0x24/0x30

         __flush_work.isra.0+0x1cc/0x360

         flush_work+0xe/0x20

         drm_mode_rmfb+0x18b/0x1d0 [drm]

         drm_mode_rmfb_ioctl+0x10/0x20 [drm]

         drm_ioctl_kernel+0xb8/0x150 [drm]

         drm_ioctl+0x243/0x560 [drm]

         __x64_sys_ioctl+0x92/0xd0

         do_syscall_64+0x59/0x90

         entry_SYSCALL_64_after_hwframe+0x72/0xdc

  } 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

  { delta: ~ 0-99, stack.stacktrace         __schedule+0xa19/0x1520

         schedule+0x6b/0x110

         schedule_timeout+0x87/0x160

         __wait_for_common+0x8f/0x190

         wait_for_completion_timeout+0x1d/0x30

         drm_atomic_helper_wait_for_flip_done+0x57/0x90 [drm_kms_helper]

         intel_atomic_commit_tail+0x8ce/0x1080 [i915]

         intel_atomic_commit_work+0x12/0x20 [i915]

         process_one_work+0x21c/0x3f0

         worker_thread+0x50/0x3e0

         kthread+0xfa/0x130

         ret_from_fork+0x29/0x50

  } hitcount:          1

  { delta: ~ 100-199, stack.stacktrace         __schedule+0xa19/0x1520

         schedule+0x6b/0x110

         schedule_hrtimeout_range_clock+0x97/0x110

         schedule_hrtimeout_range+0x13/0x20

         usleep_range_state+0x65/0x90

         pci_set_low_power_state+0x17f/0x1f0

         pci_set_power_state+0x49/0x250

         pci_finish_runtime_suspend+0x4a/0x90

         pci_pm_runtime_suspend+0xcb/0x1b0

         __rpm_callback+0x48/0x120

         rpm_callback+0x67/0x70

         rpm_suspend+0x167/0x780

         rpm_idle+0x25a/0x380

         pm_runtime_work+0x93/0xc0

         process_one_work+0x21c/0x3f0

  } hitcount:          1



  Totals:

      Hits: 89

      Entries: 11

    Hits: 10

    Entries: 7

    Dropped: 0



2.2.3 Hist trigger 'handlers' and 'actions'