android_kernel_xiaomi_sm8350/arch/x86
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
..
boot x86: use limited register constraint for setnz 2008-11-25 15:38:03 +01:00
configs x86: remove irqbalance in kernel for 32 bit 2008-10-16 16:52:52 +02:00
crypto
ia32 compat: generic compat get/settimeofday 2008-10-16 11:21:33 -07:00
include/asm tracing/function-return-tracer: change the name into function-graph-tracer 2008-11-26 01:59:45 +01:00
kernel tracing/function-return-tracer: set a more human readable output 2008-11-26 01:59:45 +01:00
kvm KVM: Fix pit memory leak if unable to allocate irq source id 2008-11-11 21:01:51 +02:00
lguest lguest: fix irq vectors. 2008-10-31 11:24:28 +11:00
lib
mach-default
mach-generic x86: make 32bit support per_cpu vector 2008-10-16 16:52:53 +02:00
mach-rdc321x
mach-voyager x86, voyager: fix smp generic helper voyager breakage 2008-11-11 12:08:53 +01:00
math-emu
mm Merge branches 'tracing/profiling', 'tracing/options' and 'tracing/urgent' into tracing/core 2008-11-23 09:10:32 +01:00
oprofile oprofile: fix an overflow in ppro code 2008-11-17 18:47:36 +01:00
pci x86/PCI: irq and pci_ids patch for Intel Ibex Peak DeviceIDs 2008-10-20 10:53:48 -07:00
power x86, hibernate: fix breakage on x86_32 with CONFIG_NUMA set 2008-11-12 23:28:51 +01:00
vdso trace: rename unlikely profiler to branch profiler 2008-11-12 22:27:58 +01:00
video
xen xen: pin correct PGD on suspend 2008-11-23 13:32:24 +01:00
Kconfig tracing/function-return-tracer: change the name into function-graph-tracer 2008-11-26 01:59:45 +01:00
Kconfig.cpu x86, bts, ftrace: a BTS ftrace plug-in prototype 2008-11-25 17:31:13 +01:00
Kconfig.debug trace: add the MMIO-tracer to the tracer menu, cleanup 2008-10-27 14:07:26 +01:00
Makefile x86, um: ... and asm-x86 move 2008-10-22 22:55:20 -07:00
Makefile_32.cpu