Yabin Cui | 67d3abd | 2015-04-16 15:26:31 -0700 | [diff] [blame] | 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_FD_H_ |
| 18 | #define SIMPLE_PERF_EVENT_FD_H_ |
| 19 | |
Yabin Cui | ed91cd9 | 2015-04-28 15:54:13 -0700 | [diff] [blame] | 20 | #include <poll.h> |
Yabin Cui | 67d3abd | 2015-04-16 15:26:31 -0700 | [diff] [blame] | 21 | #include <sys/types.h> |
| 22 | |
| 23 | #include <memory> |
| 24 | #include <string> |
| 25 | |
| 26 | #include <base/macros.h> |
| 27 | |
Yabin Cui | 323e945 | 2015-04-20 18:07:17 -0700 | [diff] [blame] | 28 | #include "perf_event.h" |
| 29 | |
Yabin Cui | 323e945 | 2015-04-20 18:07:17 -0700 | [diff] [blame] | 30 | struct PerfCounter { |
| 31 | uint64_t value; // The value of the event specified by the perf_event_file. |
| 32 | uint64_t time_enabled; // The enabled time. |
| 33 | uint64_t time_running; // The running time. |
| 34 | uint64_t id; // The id of the perf_event_file. |
| 35 | }; |
| 36 | |
Yabin Cui | 67d3abd | 2015-04-16 15:26:31 -0700 | [diff] [blame] | 37 | // EventFd represents an opened perf_event_file. |
| 38 | class EventFd { |
| 39 | public: |
Yabin Cui | ed91cd9 | 2015-04-28 15:54:13 -0700 | [diff] [blame] | 40 | static std::unique_ptr<EventFd> OpenEventFileForProcess(const perf_event_attr& attr, pid_t pid); |
| 41 | static std::unique_ptr<EventFd> OpenEventFileForCpu(const perf_event_attr& attr, int cpu); |
| 42 | static std::unique_ptr<EventFd> OpenEventFile(const perf_event_attr& attr, pid_t pid, int cpu); |
Yabin Cui | 67d3abd | 2015-04-16 15:26:31 -0700 | [diff] [blame] | 43 | |
| 44 | ~EventFd(); |
| 45 | |
| 46 | // Give information about this perf_event_file, like (event_name, pid, cpu). |
| 47 | std::string Name() const; |
| 48 | |
Yabin Cui | ed91cd9 | 2015-04-28 15:54:13 -0700 | [diff] [blame] | 49 | uint64_t Id() const; |
| 50 | |
Yabin Cui | 67d3abd | 2015-04-16 15:26:31 -0700 | [diff] [blame] | 51 | // It tells the kernel to start counting and recording events specified by this file. |
| 52 | bool EnableEvent(); |
| 53 | |
| 54 | // It tells the kernel to stop counting and recording events specified by this file. |
| 55 | bool DisableEvent(); |
| 56 | |
Yabin Cui | ed91cd9 | 2015-04-28 15:54:13 -0700 | [diff] [blame] | 57 | bool ReadCounter(PerfCounter* counter) const; |
| 58 | |
| 59 | // Call mmap() for this perf_event_file, so we can read sampled records from mapped area. |
| 60 | // mmap_pages should be power of 2. |
| 61 | bool MmapContent(size_t mmap_pages); |
| 62 | |
| 63 | // When the kernel writes new sampled records to the mapped area, we can get them by returning |
| 64 | // the start address and size of the data. |
| 65 | size_t GetAvailableMmapData(char** pdata); |
| 66 | |
| 67 | // Discard how much data we have read, so the kernel can reuse this part of mapped area to store |
| 68 | // new data. |
| 69 | void DiscardMmapData(size_t discard_size); |
| 70 | |
| 71 | // Prepare pollfd for poll() to wait on available mmap_data. |
| 72 | void PreparePollForMmapData(pollfd* poll_fd); |
Yabin Cui | 323e945 | 2015-04-20 18:07:17 -0700 | [diff] [blame] | 73 | |
Yabin Cui | 67d3abd | 2015-04-16 15:26:31 -0700 | [diff] [blame] | 74 | private: |
| 75 | EventFd(int perf_event_fd, const std::string& event_name, pid_t pid, int cpu) |
Yabin Cui | ed91cd9 | 2015-04-28 15:54:13 -0700 | [diff] [blame] | 76 | : perf_event_fd_(perf_event_fd), |
| 77 | id_(0), |
| 78 | event_name_(event_name), |
| 79 | pid_(pid), |
| 80 | cpu_(cpu), |
| 81 | mmap_addr_(nullptr), |
| 82 | mmap_len_(0) { |
Yabin Cui | 67d3abd | 2015-04-16 15:26:31 -0700 | [diff] [blame] | 83 | } |
| 84 | |
| 85 | int perf_event_fd_; |
Yabin Cui | ed91cd9 | 2015-04-28 15:54:13 -0700 | [diff] [blame] | 86 | mutable uint64_t id_; |
Yabin Cui | 67d3abd | 2015-04-16 15:26:31 -0700 | [diff] [blame] | 87 | const std::string event_name_; |
| 88 | pid_t pid_; |
| 89 | int cpu_; |
| 90 | |
Yabin Cui | ed91cd9 | 2015-04-28 15:54:13 -0700 | [diff] [blame] | 91 | void* mmap_addr_; |
| 92 | size_t mmap_len_; |
| 93 | perf_event_mmap_page* mmap_metadata_page_; // The first page of mmap_area. |
| 94 | char* mmap_data_buffer_; // Starts from the second page of mmap_area, containing records written |
| 95 | // by then kernel. |
| 96 | size_t mmap_data_buffer_size_; |
| 97 | |
Yabin Cui | 67d3abd | 2015-04-16 15:26:31 -0700 | [diff] [blame] | 98 | DISALLOW_COPY_AND_ASSIGN(EventFd); |
| 99 | }; |
| 100 | |
| 101 | #endif // SIMPLE_PERF_EVENT_FD_H_ |