Hector Dearman | 5013971 | 2018-02-23 15:43:41 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2018 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 SRC_FTRACE_READER_FTRACE_CONFIG_MUXER_H_ |
| 18 | #define SRC_FTRACE_READER_FTRACE_CONFIG_MUXER_H_ |
| 19 | |
| 20 | #include "ftrace_procfs.h" |
| 21 | #include "perfetto/ftrace_reader/ftrace_controller.h" |
| 22 | |
| 23 | namespace perfetto { |
| 24 | |
| 25 | // Ftrace is a bunch of globaly modifiable persistent state. |
| 26 | // Given a number of FtraceConfig's we need to find the best union of all |
| 27 | // the settings to make eveyone happy while also watching out for anybody |
| 28 | // messing with the ftrace settings at the same time as us. |
| 29 | |
| 30 | // Specifically FtraceConfigMuxer takes in a *requested* FtraceConfig |
| 31 | // (|RequestConfig|), makes a best effort attempt to modify the ftrace |
| 32 | // debugfs files to honor those settings without interupting other perfetto |
| 33 | // traces already in progress or other users of ftrace, then returns an |
| 34 | // FtraceConfigId representing that config or zero on failure. |
| 35 | |
| 36 | // To see which settings we actually managed to set you can call |GetConfig| |
| 37 | // and when you are finished with a config you can signal that with |
| 38 | // |RemoveConfig|. |
| 39 | class FtraceConfigMuxer { |
| 40 | public: |
Hector Dearman | c20f221 | 2018-03-08 10:39:00 +0000 | [diff] [blame^] | 41 | // The FtraceConfigMuxer and ProtoTranslationTable |
| 42 | // should outlive this instance. |
Hector Dearman | 5013971 | 2018-02-23 15:43:41 +0000 | [diff] [blame] | 43 | FtraceConfigMuxer(FtraceProcfs* ftrace, const ProtoTranslationTable* table); |
| 44 | virtual ~FtraceConfigMuxer(); |
| 45 | |
| 46 | // Ask FtraceConfigMuxer to adjust ftrace procfs settings to |
| 47 | // match the requested config. Returns an id to manage this |
| 48 | // config or zero on failure. |
| 49 | // This is best effort. FtraceConfigMuxer may not be able to adjust the |
| 50 | // buffer size right now. Events may be missing or there may be extra events |
| 51 | // (if you enable an atrace catagory we try to give you the matching events). |
| 52 | // If someone else is tracing we won't touch atrace (since it resets the |
| 53 | // buffer). |
| 54 | // To see the config you ended up with use |GetConfig|. |
| 55 | FtraceConfigId RequestConfig(const FtraceConfig& request); |
| 56 | |
| 57 | // Undo changes for the given config. Returns false iff the id is 0 |
| 58 | // or already removed. |
| 59 | bool RemoveConfig(FtraceConfigId id); |
| 60 | |
| 61 | // public for testing |
| 62 | void SetupClockForTesting(const FtraceConfig& request) { |
| 63 | SetupClock(request); |
| 64 | } |
| 65 | |
| 66 | const FtraceConfig* GetConfig(FtraceConfigId id); |
| 67 | |
| 68 | private: |
| 69 | struct FtraceState { |
| 70 | std::set<std::string> ftrace_events; |
| 71 | std::set<std::string> atrace_categories; |
| 72 | std::set<std::string> atrace_apps; |
| 73 | bool tracing_on = false; |
| 74 | bool atrace_on = false; |
| 75 | size_t cpu_buffer_size_pages = 0; |
| 76 | }; |
| 77 | |
| 78 | FtraceConfigMuxer(const FtraceConfigMuxer&) = delete; |
| 79 | FtraceConfigMuxer& operator=(const FtraceConfigMuxer&) = delete; |
| 80 | |
| 81 | void SetupClock(const FtraceConfig& request); |
| 82 | void SetupBufferSize(const FtraceConfig& request); |
Hector Dearman | 5013971 | 2018-02-23 15:43:41 +0000 | [diff] [blame] | 83 | void EnableAtrace(const FtraceConfig& request); |
| 84 | void DisableAtrace(); |
| 85 | |
| 86 | FtraceConfigId GetNextId(); |
| 87 | |
| 88 | FtraceConfigId last_id_ = 1; |
| 89 | FtraceProcfs* ftrace_; |
| 90 | const ProtoTranslationTable* table_; |
| 91 | |
| 92 | FtraceState current_state_; |
| 93 | std::map<FtraceConfigId, FtraceConfig> configs_; |
| 94 | }; |
| 95 | |
| 96 | std::set<std::string> GetFtraceEvents(const FtraceConfig& request); |
| 97 | size_t ComputeCpuBufferSizeInPages(size_t requested_buffer_size_kb); |
| 98 | |
| 99 | } // namespace perfetto |
| 100 | |
| 101 | #endif // SRC_FTRACE_READER_FTRACE_CONFIG_MUXER_H_ |