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1 /*
2  * Copyright (C) 2015 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 SIMPLE_PERF_EVENT_SELECTION_SET_H_
18 #define SIMPLE_PERF_EVENT_SELECTION_SET_H_
19 
20 #include <functional>
21 #include <map>
22 #include <vector>
23 
24 #include <android-base/macros.h>
25 
26 #include "event_fd.h"
27 #include "event_type.h"
28 #include "perf_event.h"
29 
30 struct CountersInfo {
31   const EventTypeAndModifier* event_type;
32   struct CounterInfo {
33     pid_t tid;
34     int cpu;
35     PerfCounter counter;
36   };
37   std::vector<CounterInfo> counters;
38 };
39 
40 struct pollfd;
41 
42 // EventSelectionSet helps to monitor events.
43 // Firstly, the user creates an EventSelectionSet, and adds the specific event types to monitor.
44 // Secondly, the user defines how to monitor the events (by setting enable_on_exec flag,
45 // sample frequency, etc).
46 // Then, the user can start monitoring by ordering the EventSelectionSet to open perf event files
47 // and enable events (if enable_on_exec flag isn't used).
48 // After that, the user can read counters or read mapped event records.
49 // At last, the EventSelectionSet will clean up resources at destruction automatically.
50 
51 class EventSelectionSet {
52  public:
EventSelectionSet()53   EventSelectionSet() {
54   }
55 
Empty()56   bool Empty() const {
57     return selections_.empty();
58   }
59 
60   bool AddEventType(const EventTypeAndModifier& event_type_modifier);
61 
62   void SetEnableOnExec(bool enable);
63   bool GetEnableOnExec();
64   void SampleIdAll();
65   void SetSampleFreq(uint64_t sample_freq);
66   void SetSamplePeriod(uint64_t sample_period);
67   bool SetBranchSampling(uint64_t branch_sample_type);
68   void EnableFpCallChainSampling();
69   bool EnableDwarfCallChainSampling(uint32_t dump_stack_size);
70   void SetInherit(bool enable);
71 
72   bool OpenEventFilesForCpus(const std::vector<int>& cpus);
73   bool OpenEventFilesForThreadsOnCpus(const std::vector<pid_t>& threads, std::vector<int> cpus);
74   bool ReadCounters(std::vector<CountersInfo>* counters);
75   void PreparePollForEventFiles(std::vector<pollfd>* pollfds);
76   bool MmapEventFiles(size_t mmap_pages);
77   bool ReadMmapEventData(std::function<bool(const char*, size_t)> callback);
78 
79   const perf_event_attr* FindEventAttrByType(const EventTypeAndModifier& event_type_modifier);
80   const std::vector<std::unique_ptr<EventFd>>* FindEventFdsByType(
81       const EventTypeAndModifier& event_type_modifier);
82 
83  private:
84   void UnionSampleType();
85   bool OpenEventFiles(const std::vector<pid_t>& threads, const std::vector<int>& cpus);
86 
87   struct EventSelection {
88     EventTypeAndModifier event_type_modifier;
89     perf_event_attr event_attr;
90     std::vector<std::unique_ptr<EventFd>> event_fds;
91   };
92   EventSelection* FindSelectionByType(const EventTypeAndModifier& event_type_modifier);
93 
94   std::vector<EventSelection> selections_;
95 
96   DISALLOW_COPY_AND_ASSIGN(EventSelectionSet);
97 };
98 
99 bool IsBranchSamplingSupported();
100 bool IsDwarfCallChainSamplingSupported();
101 
102 #endif  // SIMPLE_PERF_EVENT_SELECTION_SET_H_
103