1 /* 2 * Copyright (C) 2021 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef INCLUDE_PERFETTO_TRACING_TRACK_EVENT_ARGS_H_ 18 #define INCLUDE_PERFETTO_TRACING_TRACK_EVENT_ARGS_H_ 19 20 #include "perfetto/tracing/event_context.h" 21 #include "perfetto/tracing/track.h" 22 23 #include <functional> 24 25 namespace perfetto { 26 27 // A helper to add |flow_id| as a non-terminating flow id to TRACE_EVENT 28 // inline: TRACE_EVENT(..., perfetto::Flow::ProcessScoped(42)); 29 class Flow { 30 public: 31 // |flow_id| which is local within a given process (e.g. atomic counter xor'ed 32 // with feature-specific value). This value is xor'ed with Perfetto's internal 33 // process track id to attempt to ensure that it's globally-unique. 34 static PERFETTO_ALWAYS_INLINE inline std::function<void(EventContext&)> ProcessScoped(uint64_t flow_id)35 ProcessScoped(uint64_t flow_id) { 36 return Global(flow_id ^ Track::process_uuid); 37 } 38 39 // Same as above, but construct an id from a pointer. 40 // NOTE: After the object is destroyed, the value of |ptr| can be reused for a 41 // different object (in particular if the object is allocated on a stack). 42 // Please ensure that you emit a trace event with the flow id of 43 // perfetto::TerminatingFlow::FromPointer(this) from the destructor of the 44 // object to avoid accidental conflicts. 45 static PERFETTO_ALWAYS_INLINE inline std::function<void(EventContext&)> FromPointer(void * ptr)46 FromPointer(void* ptr) { 47 return ProcessScoped(reinterpret_cast<uintptr_t>(ptr)); 48 } 49 50 // Add the |flow_id|. The caller is responsible for ensuring that it's 51 // globally-unique (e.g. by generating a random value). This should be used 52 // only for flow events which cross the process boundary (e.g. IPCs). 53 static PERFETTO_ALWAYS_INLINE inline std::function<void(EventContext&)> Global(uint64_t flow_id)54 Global(uint64_t flow_id) { 55 return [flow_id](perfetto::EventContext& ctx) { 56 ctx.event()->add_flow_ids(flow_id); 57 }; 58 } 59 60 // TODO(altimin): Remove once converting a single usage in Chromium. Flow(uint64_t flow_id)61 explicit constexpr Flow(uint64_t flow_id) : flow_id_(flow_id) {} 62 operator()63 void operator()(EventContext& ctx) { ctx.event()->add_flow_ids(flow_id_); } 64 65 private: 66 uint64_t flow_id_; 67 }; 68 69 // A helper to add a given |flow_id| as a terminating flow to TRACE_EVENT 70 // inline. 71 class TerminatingFlow { 72 public: 73 // See `Flow::ProcessScoped(uint64_t)`. 74 static PERFETTO_ALWAYS_INLINE inline std::function<void(EventContext&)> ProcessScoped(uint64_t flow_id)75 ProcessScoped(uint64_t flow_id) { 76 return Global(flow_id ^ Track::process_uuid); 77 } 78 79 // See `Flow::FromPointer(void*)`. 80 static PERFETTO_ALWAYS_INLINE inline std::function<void(EventContext&)> FromPointer(void * ptr)81 FromPointer(void* ptr) { 82 return ProcessScoped(reinterpret_cast<uintptr_t>(ptr)); 83 } 84 85 // See `Flow::Global(uint64_t)`. 86 static PERFETTO_ALWAYS_INLINE inline std::function<void(EventContext&)> Global(uint64_t flow_id)87 Global(uint64_t flow_id) { 88 return [flow_id](perfetto::EventContext& ctx) { 89 ctx.event()->add_terminating_flow_ids(flow_id); 90 }; 91 } 92 }; 93 94 } // namespace perfetto 95 96 #endif // INCLUDE_PERFETTO_TRACING_TRACK_EVENT_ARGS_H_ 97