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Commit Graph

5 Commits

Author SHA1 Message Date
Frederic Weisbecker
83a8df618e tracing/function-graph-tracer: enhancements for the trace output
Impact: enhance the output of the graph-tracer

This patch applies some ideas of Ingo Molnar and Steven Rostedt.

* Output leaf functions in one line with parenthesis, semicolon and duration
  output.

* Add a second column (after cpu) for an overhead sign.
  if duration > 100 us, "!"
  if duration > 10 us, "+"
  else " "

* Print output in us with remaining nanosec: u.n

* Print duration on the right end, following the indentation of the functions.
  Use also visual clues: "-" on entry call (no duration to output) and "+" on
  return (duration output).

The name of the tracer has been fixed as well: function-branch becomes
function_branch.

Here is an example of the new output:

CPU[000]           dequeue_entity() {                    -
CPU[000]             update_curr() {                    -
CPU[000]               update_min_vruntime();                    + 0.512 us
CPU[000]             }                                + 1.504 us
CPU[000]             clear_buddies();                    + 0.481 us
CPU[000]             update_min_vruntime();                    + 0.504 us
CPU[000]           }                                + 4.557 us
CPU[000]           hrtick_update() {                    -
CPU[000]             hrtick_start_fair();                    + 0.489 us
CPU[000]           }                                + 1.443 us
CPU[000] +       }                                + 14.655 us
CPU[000] +     }                                + 15.678 us
CPU[000] +   }                                + 16.686 us
CPU[000]     msecs_to_jiffies();                    + 0.481 us
CPU[000]     put_prev_task_fair();                    + 0.504 us
CPU[000]     pick_next_task_fair();                    + 0.482 us
CPU[000]     pick_next_task_rt();                    + 0.504 us
CPU[000]     pick_next_task_fair();                    + 0.481 us
CPU[000]     pick_next_task_idle();                    + 0.489 us
CPU[000]     _spin_trylock();                    + 0.655 us
CPU[000]     _spin_unlock();                    + 0.609 us

CPU[000]  ------------8<---------- thread bash-2794 ------------8<----------

CPU[000]               finish_task_switch() {                    -
CPU[000]                 _spin_unlock_irq();                    + 0.722 us
CPU[000]               }                                + 2.369 us
CPU[000] !           }                                + 501972.605 us
CPU[000] !         }                                + 501973.763 us
CPU[000]           copy_from_read_buf() {                    -
CPU[000]             _spin_lock_irqsave();                    + 0.670 us
CPU[000]             _spin_unlock_irqrestore();                    + 0.699 us
CPU[000]             copy_to_user() {                    -
CPU[000]               might_fault() {                    -
CPU[000]                 __might_sleep();                    + 0.503 us
CPU[000]               }                                + 1.632 us
CPU[000]               __copy_to_user_ll();                    + 0.542 us
CPU[000]             }                                + 3.858 us
CPU[000]             tty_audit_add_data() {                    -
CPU[000]               _spin_lock_irq();                    + 0.609 us
CPU[000]               _spin_unlock_irq();                    + 0.624 us
CPU[000]             }                                + 3.196 us
CPU[000]             _spin_lock_irqsave();                    + 0.624 us
CPU[000]             _spin_unlock_irqrestore();                    + 0.625 us
CPU[000] +         }                                + 13.611 us
CPU[000]           copy_from_read_buf() {                    -
CPU[000]             _spin_lock_irqsave();                    + 0.624 us
CPU[000]             _spin_unlock_irqrestore();                    + 0.616 us
CPU[000]           }                                + 2.820 us
CPU[000]

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-27 10:59:14 +01:00
Steven Rostedt
437f24fb89 ftrace: add cpu annotation for function graph tracer
Impact: enhancement for function graph tracer

When run on a SMP box, the function graph tracer is confusing because
it shows the different CPUS as changes in the trace.

This patch adds the annotation of 'CPU[###]' where ### is a three digit
number. The output will look similar to this:

CPU[001]     dput() {
CPU[000] } 726
CPU[001]     } 487
CPU[000] do_softirq() {
CPU[001]   } 2221
CPU[000]   __do_softirq() {
CPU[000]     __local_bh_disable() {
CPU[001]   unroll_tree_refs() {
CPU[000]     } 569
CPU[001]   } 501
CPU[000]     rcu_process_callbacks() {
CPU[001]   kfree() {

What makes this nice is that now you can grep the file and produce
readable format for a particular CPU.

 # cat /debug/tracing/trace > /tmp/trace
 # grep '^CPU\[000\]' /tmp/trace > /tmp/trace0
 # grep '^CPU\[001\]' /tmp/trace > /tmp/trace1

Will give you:

 # head /tmp/trace0
CPU[000] ------------8<---------- thread sshd-3899 ------------8<----------
CPU[000]     inotify_dentry_parent_queue_event() {
CPU[000]     } 2531
CPU[000]     inotify_inode_queue_event() {
CPU[000]     } 505
CPU[000]   } 69626
CPU[000] } 73089
CPU[000] audit_syscall_exit() {
CPU[000]   path_put() {
CPU[000]     dput() {

 # head /tmp/trace1
CPU[001] ------------8<---------- thread pcscd-3446 ------------8<----------
CPU[001]               } 4186
CPU[001]               dput() {
CPU[001]               } 543
CPU[001]               vfs_permission() {
CPU[001]                 inode_permission() {
CPU[001]                   shmem_permission() {
CPU[001]                     generic_permission() {
CPU[001]                     } 501
CPU[001]                   } 2205

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-26 06:52:57 +01:00
Steven Rostedt
660c7f9be9 ftrace: add thread comm to function graph tracer
Impact: enhancement to function graph tracer

Export the trace_find_cmdline so the function graph tracer can
use it to print the comms of the threads.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-26 06:52:56 +01:00
Frederic Weisbecker
287b6e68ca tracing/function-return-tracer: set a more human readable output
Impact: feature

This patch sets a C-like output for the function graph tracing.
For this aim, we now call two handler for each function: one on the entry
and one other on return. This way we can draw a well-ordered call stack.

The pid of the previous trace is loosely stored to be compared against
the one of the current trace to see if there were a context switch.

Without this little feature, the call tree would seem broken at
some locations.
We could use the sched_tracer to capture these sched_events but this
way of processing is much more simpler.

2 spaces have been chosen for indentation to fit the screen while deep
calls. The time of execution in nanosecs is printed just after closed
braces, it seems more easy this way to find the corresponding function.
If the time was printed as a first column, it would be not so easy to
find the corresponding function if it is called on a deep depth.

I plan to output the return value but on 32 bits CPU, the return value
can be 32 or 64, and its difficult to guess on which case we are.
I don't know what would be the better solution on X86-32: only print
eax (low-part) or even edx (high-part).

Actually it's thee same problem when a function return a 8 bits value, the
high part of eax could contain junk values...

Here is an example of trace:

sys_read() {
  fget_light() {
  } 526
  vfs_read() {
    rw_verify_area() {
      security_file_permission() {
        cap_file_permission() {
        } 519
      } 1564
    } 2640
    do_sync_read() {
      pipe_read() {
        __might_sleep() {
        } 511
        pipe_wait() {
          prepare_to_wait() {
          } 760
          deactivate_task() {
            dequeue_task() {
              dequeue_task_fair() {
                dequeue_entity() {
                  update_curr() {
                    update_min_vruntime() {
                    } 504
                  } 1587
                  clear_buddies() {
                  } 512
                  add_cfs_task_weight() {
                  } 519
                  update_min_vruntime() {
                  } 511
                } 5602
                dequeue_entity() {
                  update_curr() {
                    update_min_vruntime() {
                    } 496
                  } 1631
                  clear_buddies() {
                  } 496
                  update_min_vruntime() {
                  } 527
                } 4580
                hrtick_update() {
                  hrtick_start_fair() {
                  } 488
                } 1489
              } 13700
            } 14949
          } 16016
          msecs_to_jiffies() {
          } 496
          put_prev_task_fair() {
          } 504
          pick_next_task_fair() {
          } 489
          pick_next_task_rt() {
          } 496
          pick_next_task_fair() {
          } 489
          pick_next_task_idle() {
          } 489

------------8<---------- thread 4 ------------8<----------

finish_task_switch() {
} 1203
do_softirq() {
  __do_softirq() {
    __local_bh_disable() {
    } 669
    rcu_process_callbacks() {
      __rcu_process_callbacks() {
        cpu_quiet() {
          rcu_start_batch() {
          } 503
        } 1647
      } 3128
      __rcu_process_callbacks() {
      } 542
    } 5362
    _local_bh_enable() {
    } 587
  } 8880
} 9986
kthread_should_stop() {
} 669
deactivate_task() {
  dequeue_task() {
    dequeue_task_fair() {
      dequeue_entity() {
        update_curr() {
          calc_delta_mine() {
          } 511
          update_min_vruntime() {
          } 511
        } 2813

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-26 01:59:45 +01:00
Frederic Weisbecker
fb52607afc tracing/function-return-tracer: change the name into function-graph-tracer
Impact: cleanup

This patch changes the name of the "return function tracer" into
function-graph-tracer which is a more suitable name for a tracing
which makes one able to retrieve the ordered call stack during
the code flow.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-26 01:59:45 +01:00