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    SubjectRe: [PATCH v2 00/15] tracing: 'hist' triggers
    On Mon, Mar 2, 2015 at 12:43 PM, Steven Rostedt <rostedt@goodmis.org> wrote:
    > On Mon, 2 Mar 2015 15:39:48 -0500
    > Steven Rostedt <rostedt@goodmis.org> wrote:
    >
    >> On Mon, 2 Mar 2015 12:33:34 -0800
    >> Alexei Starovoitov <ast@plumgrid.com> wrote:
    >>
    >> > On Mon, Mar 2, 2015 at 11:49 AM, Karim Yaghmour
    >> > <karim.yaghmour@opersys.com> wrote:
    >> > >
    >> > > On 15-03-02 02:45 PM, Steven Rostedt wrote:
    >> > >> Interesting. The Android devices I have still have it enabled (rooted,
    >> > >> but still running the stock system).
    >> > >
    >> > > I don't know that there's any policy to disable tracing on Android. The
    >> > > Android framework in fact has generally been instrumented by Google
    >> > > itself to output trace info into trace_marker. And the systrace/atrace
    >> > > tools made available to app developers need to get access to this
    >> > > tracing info. So, if Android had tracing disabled, systrace/atrace
    >> > > wouldn't work.
    >> > > https://developer.android.com/tools/debugging/systrace.html
    >> >
    >> > that's interesting. thanks for the link.
    >> >
    >> > I don't see tracing being explicitly enabled in defconfig:
    >> > https://source.android.com/devices/tech/kernel.html
    >>
    >> CONFIG_SCHED_TRACER=y
    >>
    >> That alone will enable tracing.
    >>
    >> -- Steve
    >>
    >> > or here:
    >> > https://android.googlesource.com/kernel/common/+/android-3.10/android/configs/android-recommended.cfg
    >>
    >
    > CONFIG_ENABLE_DEFAULT_TRACERS=y
    >
    > And so will that.

    good. thanks for explaining.
    all makes sense now.

    btw, that fancy systrace seems to be parsing text from trace_pipe
    https://android.googlesource.com/platform/external/chromium-trace/+/jb-dev/src/tracing/linux_perf_importer.js
    with a bunch of regex...
    including sched_switch: next_prio...


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