| /* |
| * Copyright (C) 2015 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #ifndef SIMPLE_PERF_EVENT_FD_H_ |
| #define SIMPLE_PERF_EVENT_FD_H_ |
| |
| #include <poll.h> |
| #include <sys/types.h> |
| |
| #include <memory> |
| #include <string> |
| |
| #include <base/macros.h> |
| |
| #include "perf_event.h" |
| |
| struct PerfCounter { |
| uint64_t value; // The value of the event specified by the perf_event_file. |
| uint64_t time_enabled; // The enabled time. |
| uint64_t time_running; // The running time. |
| uint64_t id; // The id of the perf_event_file. |
| }; |
| |
| // EventFd represents an opened perf_event_file. |
| class EventFd { |
| public: |
| static std::unique_ptr<EventFd> OpenEventFileForProcess(const perf_event_attr& attr, pid_t pid); |
| static std::unique_ptr<EventFd> OpenEventFileForCpu(const perf_event_attr& attr, int cpu); |
| static std::unique_ptr<EventFd> OpenEventFile(const perf_event_attr& attr, pid_t pid, int cpu); |
| |
| ~EventFd(); |
| |
| // Give information about this perf_event_file, like (event_name, pid, cpu). |
| std::string Name() const; |
| |
| uint64_t Id() const; |
| |
| // It tells the kernel to start counting and recording events specified by this file. |
| bool EnableEvent(); |
| |
| // It tells the kernel to stop counting and recording events specified by this file. |
| bool DisableEvent(); |
| |
| bool ReadCounter(PerfCounter* counter) const; |
| |
| // Call mmap() for this perf_event_file, so we can read sampled records from mapped area. |
| // mmap_pages should be power of 2. |
| bool MmapContent(size_t mmap_pages); |
| |
| // When the kernel writes new sampled records to the mapped area, we can get them by returning |
| // the start address and size of the data. |
| size_t GetAvailableMmapData(char** pdata); |
| |
| // Discard how much data we have read, so the kernel can reuse this part of mapped area to store |
| // new data. |
| void DiscardMmapData(size_t discard_size); |
| |
| // Prepare pollfd for poll() to wait on available mmap_data. |
| void PreparePollForMmapData(pollfd* poll_fd); |
| |
| private: |
| EventFd(int perf_event_fd, const std::string& event_name, pid_t pid, int cpu) |
| : perf_event_fd_(perf_event_fd), |
| id_(0), |
| event_name_(event_name), |
| pid_(pid), |
| cpu_(cpu), |
| mmap_addr_(nullptr), |
| mmap_len_(0) { |
| } |
| |
| int perf_event_fd_; |
| mutable uint64_t id_; |
| const std::string event_name_; |
| pid_t pid_; |
| int cpu_; |
| |
| void* mmap_addr_; |
| size_t mmap_len_; |
| perf_event_mmap_page* mmap_metadata_page_; // The first page of mmap_area. |
| char* mmap_data_buffer_; // Starts from the second page of mmap_area, containing records written |
| // by then kernel. |
| size_t mmap_data_buffer_size_; |
| |
| DISALLOW_COPY_AND_ASSIGN(EventFd); |
| }; |
| |
| #endif // SIMPLE_PERF_EVENT_FD_H_ |