Counter Namespace Reference

Sharded atomic counter. More...

Classes
struct	Shard
	Counter shard. More...
struct	Shards

Typedefs
using	Type = uint64_t
using	N = std::atomic< Type >
using	Pad = byte[ut::INNODB_CACHE_LINE_SIZE - sizeof(N)]
using	Function = std::function< void(const Type)>

Functions
template<size_t COUNT>
Type	add (Shards< COUNT > &shards, size_t id, size_t n)
	Increment the counter for a shard by n. More...
template<size_t COUNT>
Type	sub (Shards< COUNT > &shards, size_t id, size_t n)
	Decrement the counter for a shard by n. More...
template<size_t COUNT>
Type	inc (Shards< COUNT > &shards, size_t id)
	Increment the counter of a shard by 1. More...
template<size_t COUNT>
Type	dec (Shards< COUNT > &shards, size_t id)
	Decrement the counter of a shard by 1. More...
template<size_t COUNT>
Type	get (const Shards< COUNT > &shards, size_t id) noexcept
	Get the counter value for a shard. More...
template<size_t COUNT>
void	for_each (const Shards< COUNT > &shards, Function &&f) noexcept
	Iterate over the shards. More...
template<size_t COUNT>
Type	total (const Shards< COUNT > &shards) noexcept
	Get the total value of all shards. More...
template<size_t COUNT>
void	clear (Shards< COUNT > &shards) noexcept
	Clear the counter - reset to 0. More...
template<size_t COUNT>
void	copy (Shards< COUNT > &dst, const Shards< COUNT > &src) noexcept
	Copy the counters, overwrite destination. More...
template<size_t COUNT>
void	add (Shards< COUNT > &dst, const Shards< COUNT > &src) noexcept
	Accumulate the counters, add source to destination. More...

Variables
constexpr auto	Memory_order = std::memory_order_relaxed
	Relaxed order by default. More...

Detailed Description

Sharded atomic counter.

Typedef Documentation

Function

using Counter::Function = typedef std::function<void(const Type)>

N

using Counter::N = typedef std::atomic<Type>

Pad

using Counter::Pad = typedef byte[ut::INNODB_CACHE_LINE_SIZE - sizeof(N)]

Type

using Counter::Type = typedef uint64_t

Function Documentation

add() [1/2]

template<size_t COUNT>

void Counter::add ( Shards< COUNT > &  dst, const Shards< COUNT > &  src  )

inlinenoexcept

Accumulate the counters, add source to destination.

Parameters

[in,out]	dst	Destination shard
[in]	src	Source shard.

add() [2/2]

template<size_t COUNT>

Type Counter::add ( Shards< COUNT > &  shards, size_t  id, size_t  n  )

inline

Increment the counter for a shard by n.

Parameters

[in,out]	shards	Sharded counter to increment.
[in]	id	Shard key.
[in]	n	Number to add.

Returns

previous value.

clear()

template<size_t COUNT>

void Counter::clear ( Shards< COUNT > &  shards )

inlinenoexcept

Clear the counter - reset to 0.

Parameters

[in,out]

shards

Shards to clear.

copy()

template<size_t COUNT>

void Counter::copy ( Shards< COUNT > &  dst, const Shards< COUNT > &  src  )

inlinenoexcept

Copy the counters, overwrite destination.

Parameters

[in,out]	dst	Destination shard
[in]	src	Source shard.

dec()

template<size_t COUNT>

Type Counter::dec ( Shards< COUNT > &  shards, size_t  id  )

inline

Decrement the counter of a shard by 1.

Parameters

[in,out]	shards	Sharded counter to decrement.
[in]	id	Shard key.

Returns

previous value.

for_each()

template<size_t COUNT>

void Counter::for_each ( const Shards< COUNT > &  shards, Function &&  f  )

inlinenoexcept

Iterate over the shards.

Parameters

[in]	shards	Shards to iterate over
[in]	f	Callback function

get()

template<size_t COUNT>

Type Counter::get ( const Shards< COUNT > &  shards, size_t  id  )

inlinenoexcept

Get the counter value for a shard.

Parameters

[in,out]	shards	Sharded counter to increment.
[in]	id	Shard key.

Returns

current value.

inc()

template<size_t COUNT>

Type Counter::inc ( Shards< COUNT > &  shards, size_t  id  )

inline

Increment the counter of a shard by 1.

Parameters

[in,out]	shards	Sharded counter to increment.
[in]	id	Shard key.

Returns

previous value.

sub()

template<size_t COUNT>

Type Counter::sub ( Shards< COUNT > &  shards, size_t  id, size_t  n  )

inline

Decrement the counter for a shard by n.

Parameters

[in,out]	shards	Sharded counter to increment.
[in]	id	Shard key.
[in]	n	Number to add.

Returns

previous value.

total()

template<size_t COUNT>

Type Counter::total ( const Shards< COUNT > &  shards )

inlinenoexcept

Get the total value of all shards.

Parameters

[in]

shards

Shards to sum.

Returns

total value.

Variable Documentation

Memory_order

constexpr auto Counter::Memory_order = std::memory_order_relaxed

constexpr

Relaxed order by default.