| /* |
| * 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 <sys/types.h> |
| |
| #include <memory> |
| #include <string> |
| #include <vector> |
| |
| #include <android-base/macros.h> |
| |
| #include "IOEventLoop.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> OpenEventFile(const perf_event_attr& attr, |
| pid_t tid, int cpu, |
| EventFd* group_event_fd, |
| bool report_error = true); |
| |
| ~EventFd(); |
| |
| // Give information about this perf_event_file, like (event_name, tid, cpu). |
| std::string Name() const; |
| |
| uint64_t Id() const; |
| |
| pid_t ThreadId() const { return tid_; } |
| |
| int Cpu() const { return cpu_; } |
| |
| const perf_event_attr& attr() const { return attr_; } |
| |
| // It tells the kernel to start counting and recording events specified by |
| // this file. |
| bool EnableEvent(); |
| |
| bool ReadCounter(PerfCounter* counter) const; |
| |
| // Create mapped buffer used to receive records sent by the kernel. |
| // mmap_pages should be power of 2. |
| bool CreateMappedBuffer(size_t mmap_pages, bool report_error); |
| |
| // Share the mapped buffer used by event_fd. The two EventFds should monitor |
| // the same event on the same cpu, but have different thread ids. |
| bool ShareMappedBuffer(const EventFd& event_fd, bool report_error); |
| |
| bool HasMappedBuffer() const { return mmap_data_buffer_size_ != 0; } |
| |
| void DestroyMappedBuffer(); |
| |
| // 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(std::vector<char>& buffer, size_t& buffer_pos); |
| |
| // [callback] is called when there is data available in the mapped buffer. |
| bool StartPolling(IOEventLoop& loop, const std::function<bool()>& callback); |
| bool StopPolling(); |
| |
| private: |
| EventFd(const perf_event_attr& attr, int perf_event_fd, |
| const std::string& event_name, pid_t tid, int cpu) |
| : attr_(attr), |
| perf_event_fd_(perf_event_fd), |
| id_(0), |
| event_name_(event_name), |
| tid_(tid), |
| cpu_(cpu), |
| mmap_addr_(nullptr), |
| mmap_len_(0), |
| mmap_metadata_page_(nullptr), |
| mmap_data_buffer_(nullptr), |
| mmap_data_buffer_size_(0), |
| ioevent_ref_(nullptr) {} |
| |
| // 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); |
| |
| const perf_event_attr attr_; |
| int perf_event_fd_; |
| mutable uint64_t id_; |
| const std::string event_name_; |
| pid_t tid_; |
| 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_; // Starting from the second page of mmap_area, |
| // containing records written by then kernel. |
| size_t mmap_data_buffer_size_; |
| |
| // As mmap_data_buffer is a ring buffer, it is possible that one record is |
| // wrapped at the end of the buffer. So we need to copy records from |
| // mmap_data_buffer to data_process_buffer before processing them. |
| static std::vector<char> data_process_buffer_; |
| |
| IOEventRef ioevent_ref_; |
| |
| DISALLOW_COPY_AND_ASSIGN(EventFd); |
| }; |
| |
| bool IsEventAttrSupportedByKernel(perf_event_attr attr); |
| |
| #endif // SIMPLE_PERF_EVENT_FD_H_ |