seqan3::detail::spin_delay Class Reference

A delay for threads waiting for a shared resource. More...

#include <seqan3/utility/parallel/detail/spin_delay.hpp>

Public Member Functions
void	wait ()
	Delays the calling thread by either using active spinning or passive spinning.
Constructors, destructor and assignment
constexpr	spin_delay () noexcept=default
	Defaulted.
constexpr	spin_delay (spin_delay const &) noexcept=default
	Defaulted.
constexpr	spin_delay (spin_delay &&) noexcept=default
	Defaulted.
constexpr spin_delay &	operator= (spin_delay const &) noexcept=default
	Defaulted.
constexpr spin_delay &	operator= (spin_delay &&) noexcept=default
	Defaulted.
	~spin_delay () noexcept=default
	Defaulted.

Private Member Functions
void	pause_processor ()
	Efficient instruction to pause the CPU.

Private Attributes
int_fast32_t	current {1}
	The current waiting phase.

Static Private Attributes
static constexpr int_fast32_t	max_repetitions {16}
	The maximal number of repetitions until the thread yields.

Detailed Description

A delay for threads waiting for a shared resource.

This spin delay is used in combination with spin locks. If the thread is waiting for a shared resource it will usually waste CPU cycles until it can acquire the lock. Especially if there is a high contention on the lock this can become a performance bottleneck. This spin delay allows for more efficient spinning phases using a hybrid spinning approach. At first it does active spinning until a certain number of wait cycles has been reached. After this the thread yields.

Member Function Documentation

wait()

void seqan3::detail::spin_delay::wait ( )

inline

Delays the calling thread by either using active spinning or passive spinning.

In the first x repetitions the thread is paused using efficient CPU instructions. After x cycles of active spinning the thread will be suspended by invoking std::this_thread::yield.

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

• spin_delay.hpp