1 // Copyright 2015 The Chromium OS Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef CHROMIUMOS_WIDE_PROFILING_SAMPLE_INFO_READER_H_ 6 #define CHROMIUMOS_WIDE_PROFILING_SAMPLE_INFO_READER_H_ 7 8 #include <stdint.h> 9 10 #include "kernel/perf_event.h" 11 12 namespace quipper { 13 14 // Forward declarations of structures. 15 union perf_event; 16 typedef perf_event event_t; 17 struct perf_sample; 18 19 class SampleInfoReader { 20 public: 21 SampleInfoReader(struct perf_event_attr event_attr, bool read_cross_endian) 22 : event_attr_(event_attr), read_cross_endian_(read_cross_endian) {} 23 24 bool ReadPerfSampleInfo(const event_t& event, 25 struct perf_sample* sample) const; 26 bool WritePerfSampleInfo(const perf_sample& sample, event_t* event) const; 27 28 // Given a general perf sample format |sample_type|, return the fields of that 29 // format that are present in a sample for an event of type |event_type|. 30 // 31 // e.g. FORK and EXIT events have the fields {time, pid/tid, cpu, id}. 32 // Given a sample type with fields {ip, time, pid/tid, and period}, return 33 // the intersection of these two field sets: {time, pid/tid}. 34 // 35 // All field formats are bitfields, as defined by enum 36 // perf_event_sample_format in kernel/perf_event.h. 37 static uint64_t GetSampleFieldsForEventType(uint32_t event_type, 38 uint64_t sample_type); 39 40 // Returns the offset in bytes within a perf event structure at which the raw 41 // perf sample data is located. 42 static uint64_t GetPerfSampleDataOffset(const event_t& event); 43 44 const perf_event_attr& event_attr() const { return event_attr_; } 45 46 private: 47 // Event attribute info, which determines the contents of some perf_sample 48 // data. 49 struct perf_event_attr event_attr_; 50 51 // Set this flag if values (uint32s and uint64s) should be endian-swapped 52 // during reads. 53 bool read_cross_endian_; 54 }; 55 56 } // namespace quipper 57 58 #endif // CHROMIUMOS_WIDE_PROFILING_SAMPLE_INFO_READER_H_ 59
