1// Licensed to the Apache Software Foundation (ASF) under one
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9// http://www.apache.org/licenses/LICENSE-2.0
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17
18// From Apache Impala (incubating) as of 2016-01-29. Pared down to a minimal
19// set of functions needed for Apache Arrow / Apache parquet-cpp
20
21#ifndef ARROW_UTIL_CPU_INFO_H
22#define ARROW_UTIL_CPU_INFO_H
23
24#include <cstdint>
25#include <string>
26
27#include "arrow/util/visibility.h"
28
29namespace arrow {
30namespace internal {
31
32/// CpuInfo is an interface to query for cpu information at runtime. The caller can
33/// ask for the sizes of the caches and what hardware features are supported.
34/// On Linux, this information is pulled from a couple of sys files (/proc/cpuinfo and
35/// /sys/devices)
36class ARROW_EXPORT CpuInfo {
37 public:
38 static constexpr int64_t SSSE3 = (1 << 1);
39 static constexpr int64_t SSE4_1 = (1 << 2);
40 static constexpr int64_t SSE4_2 = (1 << 3);
41 static constexpr int64_t POPCNT = (1 << 4);
42
43 /// Cache enums for L1 (data), L2 and L3
44 enum CacheLevel {
45 L1_CACHE = 0,
46 L2_CACHE = 1,
47 L3_CACHE = 2,
48 };
49
50 static CpuInfo* GetInstance();
51
52 /// Determine if the CPU meets the minimum CPU requirements and if not, issue an error
53 /// and terminate.
54 void VerifyCpuRequirements();
55
56 /// Returns all the flags for this cpu
57 int64_t hardware_flags();
58
59 /// Returns whether of not the cpu supports this flag
60 bool IsSupported(int64_t flag) const { return (hardware_flags_ & flag) != 0; }
61
62 /// \brief The processor supports SSE4.2 and the Arrow libraries are built
63 /// with support for it
64 bool CanUseSSE4_2() const;
65
66 /// Toggle a hardware feature on and off. It is not valid to turn on a feature
67 /// that the underlying hardware cannot support. This is useful for testing.
68 void EnableFeature(int64_t flag, bool enable);
69
70 /// Returns the size of the cache in KB at this cache level
71 int64_t CacheSize(CacheLevel level);
72
73 /// Returns the number of cpu cycles per millisecond
74 int64_t cycles_per_ms();
75
76 /// Returns the number of cores (including hyper-threaded) on this machine.
77 int num_cores();
78
79 /// Returns the model name of the cpu (e.g. Intel i7-2600)
80 std::string model_name();
81
82 private:
83 CpuInfo();
84
85 void Init();
86
87 /// Inits CPU cache size variables with default values
88 void SetDefaultCacheSize();
89
90 int64_t hardware_flags_;
91 int64_t original_hardware_flags_;
92 int64_t cache_sizes_[L3_CACHE + 1];
93 int64_t cycles_per_ms_;
94 int num_cores_;
95 std::string model_name_;
96};
97
98} // namespace internal
99} // namespace arrow
100
101#endif // ARROW_UTIL_CPU_INFO_H
102