jmmcg::LIBJMMCG_VER_NAMESPACE::cpu_timer::in_order Class Reference

Measure a time interval using derivatives of the CPU instruction RDTSC. More...

#include <hp_timer.hpp>

Public Member Functions
REALLY_FORCE_INLINE	in_order (element_type &d) noexcept(true)
REALLY_FORCE_INLINE	~in_order () noexcept(true)

Static Public Member Functions
static element_type REALLY_FORCE_INLINE	get_start () noexcept(true)
static element_type REALLY_FORCE_INLINE	get_end () noexcept(true)
static element_type REALLY_FORCE_INLINE	now () noexcept(true)

Detailed Description

Measure a time interval using derivatives of the CPU instruction RDTSC.

The design of this code is directly influenced from [1]. Note that instructions are emitted to ensure that the pipeline in the CPU is serialised at the start of the interval and partially serialised at the end, so the interval measurement is fairly accurate. Note that this costs approximately 20 clock cycles.

[1] "How to Benchmark Code Execution Times on Intel® IA-32 and IA-64 Instruction Set Architectures",

Definition at line 147 of file hp_timer.hpp.

Constructor & Destructor Documentation

in_order()

REALLY_FORCE_INLINE jmmcg::LIBJMMCG_VER_NAMESPACE::cpu_timer::in_order::in_order ( element_type &  d )

inlineexplicitnoexcept

Note that this serialises the CPU.

Definition at line 166 of file hp_timer.hpp.

References get_start().

~in_order()

REALLY_FORCE_INLINE jmmcg::LIBJMMCG_VER_NAMESPACE::cpu_timer::in_order::~in_order ( )

inlinenoexcept

Note that instructions issued before this dtor will complete before the dtor, but those issued after may be scheduled before the dtor, if the super-scalar CPU has sufficient resources.

Definition at line 173 of file hp_timer.hpp.

References get_end().

Member Function Documentation

get_end()

static element_type REALLY_FORCE_INLINE jmmcg::LIBJMMCG_VER_NAMESPACE::cpu_timer::in_order::get_end ( )

inlinestaticnoexcept

Definition at line 155 of file hp_timer.hpp.

Referenced by now(), jmmcg::LIBJMMCG_VER_NAMESPACE::cpu_timer::pause_for_usec(), ~in_order(), and jmmcg::LIBJMMCG_VER_NAMESPACE::latency_timestamps_itf::period::~period().

get_start()

static element_type REALLY_FORCE_INLINE jmmcg::LIBJMMCG_VER_NAMESPACE::cpu_timer::in_order::get_start ( )

inlinestaticnoexcept

Definition at line 149 of file hp_timer.hpp.

Referenced by in_order(), jmmcg::LIBJMMCG_VER_NAMESPACE::cpu_timer::pause_for_usec(), and jmmcg::LIBJMMCG_VER_NAMESPACE::latency_timestamps_itf::period::period().

now()

static element_type REALLY_FORCE_INLINE jmmcg::LIBJMMCG_VER_NAMESPACE::cpu_timer::in_order::now ( )

inlinestaticnoexcept

Definition at line 159 of file hp_timer.hpp.

References get_end().

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The documentation for this class was generated from the following file:

• core/hp_timer.hpp