roc::core::Seqlock< T > Class Template Reference

Seqlock. More...

#include <seqlock.h>

Inheritance diagram for roc::core::Seqlock< T >:

Public Member Functions
	Seqlock (T value)
	Initialize with given value.
seqlock_version_t	version () const
	Load value version. Wait-free.
bool	try_store (const T &value)
	Store value. Can be called concurrently, but only one concurrent call will succeed. Is both lock-free and wait-free, i.e. it never waits for sleeping threads and never spins. After this call returns, any thread calling wait_load() is guaranteed to get the updated value, and try_load() is guaranteed either return the updated value or fail (if changes are not fully published yet).
bool	try_store_v (const T &value, seqlock_version_t &ver)
	Store value. Like try_store(), but also returns updated version.
void	exclusive_store (const T &value)
	Store value. Can NOT be called concurrently, assumes that writes are serialized. Is both lock-free and wait-free, i.e. it never waits for sleeping threads and never spins. After this call returns, any thread calling wait_load() is guaranteed to get the updated value, and try_load() is guaranteed either return the updated value or fail (if changes are not fully published yet).
void	exclusive_store_v (const T &value, seqlock_version_t &ver)
	Store value. Like exclusive_store(), but also returns updated version.
bool	try_load (T &value) const
	Try to load value. Returns true if the value was loaded. May return false if concurrent store is currently in progress. Is both lock-free and wait-free, i.e. it never waits for sleeping threads and never spins.
bool	try_load_v (T &value, seqlock_version_t &ver) const
	Try to load value and version. Like try_load(), but also returns version.
T	wait_load () const
	Load value. May spin until concurrent store completes. Is NOT lock-free (or wait-free).
void	wait_load_v (T &value, seqlock_version_t &ver) const
	Load value and version. Like wait_load(), but also returns version.

Detailed Description

template<class T>
class roc::core::Seqlock< T >

Seqlock.

Provides safe concurrent access to a single value. Provides sequential consistency. Optimized for infrequent writes and frequent reads. Writes are lock-free and take priority over reads.

See details on the barriers here: https://elixir.bootlin.com/linux/latest/source/include/linux/seqlock.h https://www.hpl.hp.com/techreports/2012/HPL-2012-68.pdf

Definition at line 31 of file seqlock.h.

Constructor & Destructor Documentation

Seqlock()

template<class T>

roc::core::Seqlock< T >::Seqlock ( T value )

inlineexplicit

Initialize with given value.

Definition at line 34 of file seqlock.h.

Member Function Documentation

exclusive_store()

template<class T>

void roc::core::Seqlock< T >::exclusive_store ( const T & value )

inline

Store value. Can NOT be called concurrently, assumes that writes are serialized. Is both lock-free and wait-free, i.e. it never waits for sleeping threads and never spins. After this call returns, any thread calling wait_load() is guaranteed to get the updated value, and try_load() is guaranteed either return the updated value or fail (if changes are not fully published yet).

Definition at line 69 of file seqlock.h.

exclusive_store_v()

template<class T>

void roc::core::Seqlock< T >::exclusive_store_v ( const T & value, seqlock_version_t & ver )

inline

Store value. Like exclusive_store(), but also returns updated version.

Definition at line 76 of file seqlock.h.

try_load()

template<class T>

bool roc::core::Seqlock< T >::try_load ( T & value ) const

inline

Try to load value. Returns true if the value was loaded. May return false if concurrent store is currently in progress. Is both lock-free and wait-free, i.e. it never waits for sleeping threads and never spins.

Definition at line 85 of file seqlock.h.

try_load_v()

template<class T>

bool roc::core::Seqlock< T >::try_load_v ( T & value, seqlock_version_t & ver ) const

inline

Try to load value and version. Like try_load(), but also returns version.

Definition at line 92 of file seqlock.h.

try_store()

template<class T>

bool roc::core::Seqlock< T >::try_store ( const T & value )

inline

Store value. Can be called concurrently, but only one concurrent call will succeed. Is both lock-free and wait-free, i.e. it never waits for sleeping threads and never spins. After this call returns, any thread calling wait_load() is guaranteed to get the updated value, and try_load() is guaranteed either return the updated value or fail (if changes are not fully published yet).

Definition at line 51 of file seqlock.h.

try_store_v()

template<class T>

bool roc::core::Seqlock< T >::try_store_v ( const T & value, seqlock_version_t & ver )

inline

Store value. Like try_store(), but also returns updated version.

Definition at line 58 of file seqlock.h.

version()

template<class T>

seqlock_version_t roc::core::Seqlock< T >::version ( ) const

inline

Load value version. Wait-free.

Definition at line 40 of file seqlock.h.

wait_load()

template<class T>

T roc::core::Seqlock< T >::wait_load ( ) const

inline

Load value. May spin until concurrent store completes. Is NOT lock-free (or wait-free).

Definition at line 99 of file seqlock.h.

wait_load_v()

template<class T>

void roc::core::Seqlock< T >::wait_load_v ( T & value, seqlock_version_t & ver ) const

inline

Load value and version. Like wait_load(), but also returns version.

Definition at line 108 of file seqlock.h.

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

• roc_core/seqlock.h