diff options
Diffstat (limited to 'kernel/Documentation/trace/ftrace.txt')
| -rw-r--r-- | kernel/Documentation/trace/ftrace.txt | 83 |
1 files changed, 68 insertions, 15 deletions
diff --git a/kernel/Documentation/trace/ftrace.txt b/kernel/Documentation/trace/ftrace.txt index 572ca9236..f52f297cb 100644 --- a/kernel/Documentation/trace/ftrace.txt +++ b/kernel/Documentation/trace/ftrace.txt @@ -108,8 +108,8 @@ of ftrace. Here is a list of some of the key files: data is read from this file, it is consumed, and will not be read again with a sequential read. The "trace" file is static, and if the tracer is not - adding more data,they will display the same - information every time they are read. + adding more data, it will display the same + information every time it is read. trace_options: @@ -204,6 +204,12 @@ of ftrace. Here is a list of some of the key files: Have the function tracer only trace a single thread. + set_event_pid: + + Have the events only trace a task with a PID listed in this file. + Note, sched_switch and sched_wake_up will also trace events + listed in this file. + set_graph_function: Set a "trigger" function where tracing should start @@ -346,6 +352,11 @@ of ftrace. Here is a list of some of the key files: x86-tsc: Architectures may define their own clocks. For example, x86 uses its own TSC cycle clock here. + ppc-tb: This uses the powerpc timebase register value. + This is in sync across CPUs and can also be used + to correlate events across hypervisor/guest if + tb_offset is known. + To set a clock, simply echo the clock name into this file. echo global > trace_clock @@ -686,6 +697,8 @@ The above is mostly meaningful for kernel developers. The marks are determined by the difference between this current trace and the next trace. '$' - greater than 1 second + '@' - greater than 100 milisecond + '*' - greater than 10 milisecond '#' - greater than 1000 microsecond '!' - greater than 100 microsecond '+' - greater than 10 microsecond @@ -1939,26 +1952,49 @@ want, depending on your needs. ie: - 0) | up_write() { - 0) 0.646 us | _spin_lock_irqsave(); - 0) 0.684 us | _spin_unlock_irqrestore(); - 0) 3.123 us | } - 0) 0.548 us | fput(); - 0) + 58.628 us | } + 3) # 1837.709 us | } /* __switch_to */ + 3) | finish_task_switch() { + 3) 0.313 us | _raw_spin_unlock_irq(); + 3) 3.177 us | } + 3) # 1889.063 us | } /* __schedule */ + 3) ! 140.417 us | } /* __schedule */ + 3) # 2034.948 us | } /* schedule */ + 3) * 33998.59 us | } /* schedule_preempt_disabled */ [...] - 0) | putname() { - 0) | kmem_cache_free() { - 0) 0.518 us | __phys_addr(); - 0) 1.757 us | } - 0) 2.861 us | } - 0) ! 115.305 us | } - 0) ! 116.402 us | } + 1) 0.260 us | msecs_to_jiffies(); + 1) 0.313 us | __rcu_read_unlock(); + 1) + 61.770 us | } + 1) + 64.479 us | } + 1) 0.313 us | rcu_bh_qs(); + 1) 0.313 us | __local_bh_enable(); + 1) ! 217.240 us | } + 1) 0.365 us | idle_cpu(); + 1) | rcu_irq_exit() { + 1) 0.417 us | rcu_eqs_enter_common.isra.47(); + 1) 3.125 us | } + 1) ! 227.812 us | } + 1) ! 457.395 us | } + 1) @ 119760.2 us | } + + [...] + + 2) | handle_IPI() { + 1) 6.979 us | } + 2) 0.417 us | scheduler_ipi(); + 1) 9.791 us | } + 1) + 12.917 us | } + 2) 3.490 us | } + 1) + 15.729 us | } + 1) + 18.542 us | } + 2) $ 3594274 us | } + means that the function exceeded 10 usecs. ! means that the function exceeded 100 usecs. # means that the function exceeded 1000 usecs. + * means that the function exceeded 10 msecs. + @ means that the function exceeded 100 msecs. $ means that the function exceeded 1 sec. @@ -2407,6 +2443,23 @@ The following commands are supported: echo '!writeback*:mod:ext3' >> set_ftrace_filter + Mod command supports module globbing. Disable tracing for all + functions except a specific module: + + echo '!*:mod:!ext3' >> set_ftrace_filter + + Disable tracing for all modules, but still trace kernel: + + echo '!*:mod:*' >> set_ftrace_filter + + Enable filter only for kernel: + + echo '*write*:mod:!*' >> set_ftrace_filter + + Enable filter for module globbing: + + echo '*write*:mod:*snd*' >> set_ftrace_filter + - traceon/traceoff These commands turn tracing on and off when the specified functions are hit. The parameter determines how many times the |