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_ver (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 srialized. 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_ver (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_ver (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_ver (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 43 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 46 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 srialized. 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 82 of file seqlock.h.

exclusive_store_ver()

template<class T >

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

inline

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

Definition at line 89 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 98 of file seqlock.h.

try_load_ver()

template<class T >

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

inline

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

Definition at line 105 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 64 of file seqlock.h.

try_store_ver()

template<class T >

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

inline

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

Definition at line 71 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 53 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 112 of file seqlock.h.

wait_load_ver()

template<class T >

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

inline

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

Definition at line 121 of file seqlock.h.

---

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

• roc_core/seqlock.h