blob: 506917f16cdcb1f205c4555bf5088a806724e39a (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
|
//===-- PerfHelper.h ------------------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
///
/// \file
/// Helpers for measuring perf events.
///
//===----------------------------------------------------------------------===//
#ifndef LLVM_TOOLS_LLVM_EXEGESIS_PERFHELPER_H
#define LLVM_TOOLS_LLVM_EXEGESIS_PERFHELPER_H
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Config/config.h"
#include "llvm/Support/Error.h"
#include <cstdint>
#include <functional>
#include <memory>
struct perf_event_attr;
namespace llvm {
namespace exegesis {
namespace pfm {
// Returns true on error.
bool pfmInitialize();
void pfmTerminate();
// Retrieves the encoding for the event described by pfm_event_string.
// NOTE: pfm_initialize() must be called before creating PerfEvent objects.
class PerfEvent {
public:
// http://perfmon2.sourceforge.net/manv4/libpfm.html
// Events are expressed as strings. e.g. "INSTRUCTION_RETIRED"
explicit PerfEvent(StringRef PfmEventString);
PerfEvent(const PerfEvent &) = delete;
PerfEvent(PerfEvent &&other);
~PerfEvent();
// The pfm_event_string passed at construction time.
StringRef name() const;
// Whether the event was successfully created.
bool valid() const;
// The encoded event to be passed to the Kernel.
const perf_event_attr *attribute() const;
// The fully qualified name for the event.
// e.g. "snb_ep::INSTRUCTION_RETIRED:e=0:i=0:c=0:t=0:u=1:k=0:mg=0:mh=1"
StringRef getPfmEventString() const;
protected:
PerfEvent() = default;
std::string EventString;
std::string FullQualifiedEventString;
perf_event_attr *Attr;
};
// Uses a valid PerfEvent to configure the Kernel so we can measure the
// underlying event.
class Counter {
public:
// event: the PerfEvent to measure.
explicit Counter(PerfEvent &&event);
Counter(const Counter &) = delete;
Counter(Counter &&other) = default;
virtual ~Counter();
/// Starts the measurement of the event.
virtual void start();
/// Stops the measurement of the event.
void stop();
/// Returns the current value of the counter or -1 if it cannot be read.
int64_t read() const;
/// Returns the current value of the counter or error if it cannot be read.
/// FunctionBytes: The benchmark function being executed.
/// This is used to filter out the measurements to ensure they are only
/// within the benchmarked code.
/// If empty (or not specified), then no filtering will be done.
/// Not all counters choose to use this.
virtual llvm::Expected<llvm::SmallVector<int64_t, 4>>
readOrError(StringRef FunctionBytes = StringRef()) const;
virtual int numValues() const;
protected:
PerfEvent Event;
#ifdef HAVE_LIBPFM
int FileDescriptor = -1;
#endif
};
} // namespace pfm
} // namespace exegesis
} // namespace llvm
#endif // LLVM_TOOLS_LLVM_EXEGESIS_PERFHELPER_H
|
