Why cannot I enable tracing?

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According to the README file in /sys/kernel/debug/tracing/README, doing echo 1 > tracing_on should be a quick way to enable tracing. No matter how many times I execute this (as root), the value in tracing_on still remains 0. Why is that? How can I debug this further? There is no output in dmesg



tracing mini-HOWTO:

# echo 0 > tracing_on : quick way to disable tracing
# echo 1 > tracing_on : quick way to re-enable tracing

Important files:
trace - The static contents of the buffer
To clear the buffer write into this file: echo > trace
trace_pipe - A consuming read to see the contents of the buffer
current_tracer - function and latency tracers









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    0















    According to the README file in /sys/kernel/debug/tracing/README, doing echo 1 > tracing_on should be a quick way to enable tracing. No matter how many times I execute this (as root), the value in tracing_on still remains 0. Why is that? How can I debug this further? There is no output in dmesg



    tracing mini-HOWTO:

    # echo 0 > tracing_on : quick way to disable tracing
    # echo 1 > tracing_on : quick way to re-enable tracing

    Important files:
    trace - The static contents of the buffer
    To clear the buffer write into this file: echo > trace
    trace_pipe - A consuming read to see the contents of the buffer
    current_tracer - function and latency tracers









    share|improve this question
























      0












      0








      0








      According to the README file in /sys/kernel/debug/tracing/README, doing echo 1 > tracing_on should be a quick way to enable tracing. No matter how many times I execute this (as root), the value in tracing_on still remains 0. Why is that? How can I debug this further? There is no output in dmesg



      tracing mini-HOWTO:

      # echo 0 > tracing_on : quick way to disable tracing
      # echo 1 > tracing_on : quick way to re-enable tracing

      Important files:
      trace - The static contents of the buffer
      To clear the buffer write into this file: echo > trace
      trace_pipe - A consuming read to see the contents of the buffer
      current_tracer - function and latency tracers









      share|improve this question














      According to the README file in /sys/kernel/debug/tracing/README, doing echo 1 > tracing_on should be a quick way to enable tracing. No matter how many times I execute this (as root), the value in tracing_on still remains 0. Why is that? How can I debug this further? There is no output in dmesg



      tracing mini-HOWTO:

      # echo 0 > tracing_on : quick way to disable tracing
      # echo 1 > tracing_on : quick way to re-enable tracing

      Important files:
      trace - The static contents of the buffer
      To clear the buffer write into this file: echo > trace
      trace_pipe - A consuming read to see the contents of the buffer
      current_tracer - function and latency tracers






      linux linux-kernel tracing






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      asked Feb 25 at 9:23









      oligofrenoligofren

      1499




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          To get this working I first had to say what to trace! To trace function calls I did this:



          sudo -s # need to be root to be able to look inside /sys/kernel/debug
          cd /sys/kernel/debug/tracing
          echo function > current_tracer # trace function calls
          echo SyS_inotify_add_watch > set_ftrace_filter # limit what to trace


          Doing that, implicitly set the tracing flag to on, as



          cat tracing_on 
          1


          Now you can also disable it



          echo 0 > tracing_on





          share|improve this answer






















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            To get this working I first had to say what to trace! To trace function calls I did this:



            sudo -s # need to be root to be able to look inside /sys/kernel/debug
            cd /sys/kernel/debug/tracing
            echo function > current_tracer # trace function calls
            echo SyS_inotify_add_watch > set_ftrace_filter # limit what to trace


            Doing that, implicitly set the tracing flag to on, as



            cat tracing_on 
            1


            Now you can also disable it



            echo 0 > tracing_on





            share|improve this answer



























              0














              To get this working I first had to say what to trace! To trace function calls I did this:



              sudo -s # need to be root to be able to look inside /sys/kernel/debug
              cd /sys/kernel/debug/tracing
              echo function > current_tracer # trace function calls
              echo SyS_inotify_add_watch > set_ftrace_filter # limit what to trace


              Doing that, implicitly set the tracing flag to on, as



              cat tracing_on 
              1


              Now you can also disable it



              echo 0 > tracing_on





              share|improve this answer

























                0












                0








                0







                To get this working I first had to say what to trace! To trace function calls I did this:



                sudo -s # need to be root to be able to look inside /sys/kernel/debug
                cd /sys/kernel/debug/tracing
                echo function > current_tracer # trace function calls
                echo SyS_inotify_add_watch > set_ftrace_filter # limit what to trace


                Doing that, implicitly set the tracing flag to on, as



                cat tracing_on 
                1


                Now you can also disable it



                echo 0 > tracing_on





                share|improve this answer













                To get this working I first had to say what to trace! To trace function calls I did this:



                sudo -s # need to be root to be able to look inside /sys/kernel/debug
                cd /sys/kernel/debug/tracing
                echo function > current_tracer # trace function calls
                echo SyS_inotify_add_watch > set_ftrace_filter # limit what to trace


                Doing that, implicitly set the tracing flag to on, as



                cat tracing_on 
                1


                Now you can also disable it



                echo 0 > tracing_on






                share|improve this answer












                share|improve this answer



                share|improve this answer










                answered Feb 25 at 9:23









                oligofrenoligofren

                1499




                1499



























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