// Copyright 2015 The Chromium OS Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef CHROMIUMOS_WIDE_PROFILING_SAMPLE_INFO_READER_H_
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#define CHROMIUMOS_WIDE_PROFILING_SAMPLE_INFO_READER_H_
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#include <stdint.h>
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#include "kernel/perf_event.h"
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namespace quipper {
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// Forward declarations of structures.
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union perf_event;
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typedef perf_event event_t;
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struct perf_sample;
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class SampleInfoReader {
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public:
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SampleInfoReader(struct perf_event_attr event_attr, bool read_cross_endian)
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: event_attr_(event_attr), read_cross_endian_(read_cross_endian) {}
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bool ReadPerfSampleInfo(const event_t& event,
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struct perf_sample* sample) const;
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bool WritePerfSampleInfo(const perf_sample& sample, event_t* event) const;
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// Given a general perf sample format |sample_type|, return the fields of that
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// format that are present in a sample for an event of type |event_type|.
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//
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// e.g. FORK and EXIT events have the fields {time, pid/tid, cpu, id}.
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// Given a sample type with fields {ip, time, pid/tid, and period}, return
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// the intersection of these two field sets: {time, pid/tid}.
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//
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// All field formats are bitfields, as defined by enum
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// perf_event_sample_format in kernel/perf_event.h.
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static uint64_t GetSampleFieldsForEventType(uint32_t event_type,
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uint64_t sample_type);
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// Returns the offset in bytes within a perf event structure at which the raw
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// perf sample data is located.
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static uint64_t GetPerfSampleDataOffset(const event_t& event);
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const perf_event_attr& event_attr() const { return event_attr_; }
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private:
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// Event attribute info, which determines the contents of some perf_sample
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// data.
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struct perf_event_attr event_attr_;
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// Set this flag if values (uint32s and uint64s) should be endian-swapped
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// during reads.
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bool read_cross_endian_;
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};
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} // namespace quipper
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#endif // CHROMIUMOS_WIDE_PROFILING_SAMPLE_INFO_READER_H_
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