| 1 | ===============================
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| 2 | The Linux Kernel Tracepoint API
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| 3 | ===============================
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| 4 |
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| 5 | :Author: Jason Baron
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| 6 | :Author: William Cohen
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| 7 |
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| 8 | Introduction
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| 9 | ============
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| 10 |
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| 11 | Tracepoints are static probe points that are located in strategic points
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| 12 | throughout the kernel. 'Probes' register/unregister with tracepoints via
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| 13 | a callback mechanism. The 'probes' are strictly typed functions that are
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| 14 | passed a unique set of parameters defined by each tracepoint.
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| 15 |
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| 16 | From this simple callback mechanism, 'probes' can be used to profile,
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| 17 | debug, and understand kernel behavior. There are a number of tools that
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| 18 | provide a framework for using 'probes'. These tools include Systemtap,
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| 19 | ftrace, and LTTng.
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| 20 |
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| 21 | Tracepoints are defined in a number of header files via various macros.
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| 22 | Thus, the purpose of this document is to provide a clear accounting of
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| 23 | the available tracepoints. The intention is to understand not only what
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| 24 | tracepoints are available but also to understand where future
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| 25 | tracepoints might be added.
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| 26 |
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| 27 | The API presented has functions of the form:
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| 28 | ``trace_tracepointname(function parameters)``. These are the tracepoints
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| 29 | callbacks that are found throughout the code. Registering and
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| 30 | unregistering probes with these callback sites is covered in the
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| 31 | ``Documentation/trace/*`` directory.
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| 32 |
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| 33 | IRQ
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| 34 | ===
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| 35 |
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| 36 | .. kernel-doc:: include/trace/events/irq.h
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| 37 | :internal:
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| 38 |
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| 39 | SIGNAL
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| 40 | ======
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| 41 |
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| 42 | .. kernel-doc:: include/trace/events/signal.h
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| 43 | :internal:
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| 44 |
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| 45 | Block IO
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| 46 | ========
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| 47 |
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| 48 | .. kernel-doc:: include/trace/events/block.h
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| 49 | :internal:
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| 50 |
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| 51 | Workqueue
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| 52 | =========
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| 53 |
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| 54 | .. kernel-doc:: include/trace/events/workqueue.h
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| 55 | :internal:
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