A BlockingContext is like a media object that facilitates the communications for the Clients that it is holding. Each Client is powered by a single OS thread. a Client needs to be started once and only once to a single BlockingContext before any messages sending happens - typically in the initialization stage in main(), undefined behavior otherwise.
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#include <BlockingContext.hpp>
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| BlockingContext () |
| trivial ctor
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template<typename Client , typename DeliverPred = deliverAll> |
void | start (Client &c, size_t capacity=1024, size_t maxItemSize=max_size_in_tuple< typename Client::Interests >::value, uint64_t cpuAffinity=0, time::Duration maxBlockingTime=time::Duration::seconds(1), DeliverPred &&pred=DeliverPred()) |
| start a client within the Context. The client is powered by a single OS thread. More...
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template<typename LoadSharingClientPtrIt , typename DeliverPred = deliverAll> |
void | start (LoadSharingClientPtrIt begin, LoadSharingClientPtrIt end, size_t capacity=1024, size_t maxItemSize=max_size_in_tuple< typename std::remove_reference< decltype(**LoadSharingClientPtrIt())>::type::Interests >::value, uint64_t cpuAffinity=0, time::Duration maxBlockingTime=time::Duration::seconds(1), DeliverPred &&pred=DeliverPred()) |
| start a group of clients within the Context that collectively processing messages in a load sharing manner. Each client is powered by a single OS thread More...
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void | stop () |
| stop the message dispatching - asynchronously More...
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void | join () |
| wait until all threads of the Context exit More...
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template<typename Message > |
std::enable_if< can_handle< Message >::value, void >::type | send (Message &&m) |
| send a message to the BlockingContext to dispatch More...
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template<typename Message , typename ... Args> |
std::enable_if< can_handle< Message >::value, void >::type | sendInPlace (Args &&... args) |
| send a message by directly constructing the message in receiving message queue More...
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template<typename Message > |
std::enable_if< can_handle< Message >::value, bool >::type | trySend (Message &&m, time::Duration timeout=time::Duration::seconds(0)) |
| best effort to send a message to via the BlockingContext More...
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template<typename Message , typename ... Args> |
std::enable_if< can_handle< Message >::value, bool >::type | trySendInPlace (Args &&... args) |
| best effort to send a message by directly constructing the message in receiving message queue More...
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template<typename ForwardIt > |
std::enable_if< can_handle< decltype(*(ForwardIt()))>::value, void >::type | send (ForwardIt begin, size_t n) |
| send a range of messages via the BlockingContext More...
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template<typename... MessageTuples>
class hmbdc::app::BlockingContext< MessageTuples >
A BlockingContext is like a media object that facilitates the communications for the Clients that it is holding. Each Client is powered by a single OS thread. a Client needs to be started once and only once to a single BlockingContext before any messages sending happens - typically in the initialization stage in main(), undefined behavior otherwise.
a Client running in such a BlockingContext utilizing OS's blocking mechanism and takes less CPU time. The Client's responding time scales better when the number of Clients greatly exceeds the availlable CPUs in the system and the effective message rate for a Client tends to be low.
- Template Parameters
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MessageTuples | std tuple capturing the Messages that the Context is supposed to deliver. Messages that not listed here are silently dropped to ensure loose coupling between senders and receivers |
◆ join()
template<typename... MessageTuples>
wait until all threads of the Context exit
blocking call
◆ send() [1/2]
template<typename... MessageTuples>
template<typename Message >
send a message to the BlockingContext to dispatch
only the Clients that handles the Message will get it This function is threadsafe, which means you can call it anywhere in the code
- Template Parameters
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- Parameters
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◆ send() [2/2]
template<typename... MessageTuples>
template<typename ForwardIt >
send a range of messages via the BlockingContext
- only checking with diliverPred using the first message
only the Clients that handles the Message will get it of course This function is threadsafe, which means you can call it anywhere in the code
- Parameters
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begin | a forward iterator point at the start of the range |
n | length of the range |
◆ sendInPlace()
template<typename... MessageTuples>
template<typename Message , typename ... Args>
send a message by directly constructing the message in receiving message queue
since the message only exists after being deleivered, the DeliverPred is not called to decide if it should be delivered
- Parameters
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- Template Parameters
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Message | type |
typename | ... Args args |
◆ start() [1/2]
template<typename... MessageTuples>
template<typename Client , typename DeliverPred = deliverAll>
start a client within the Context. The client is powered by a single OS thread.
it is ok if a Client is blocking, if its own buffer is not full, it doesn't affect other Client's capabilities of receiving Messages
- Template Parameters
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Client | actual Client type |
DeliverPred | a condition functor deciding if a message should be delivered to a Client, which provides filtering before the Message type filtering. It improves performance in the way it could potentially reduce the unblocking times of thread |
Usage example: //the following Pred verifies srcId matches for Response, and let all other Messages types //deliver
struct Pred {
Pred(uint16_t srcId)
: srcId(srcId){}
bool operator()(Response const& resp) {
return resp.srcId == srcId;
}
template <typename M>
bool operator()(M const&) {return true;}
uint16_t srcId;
};
- Parameters
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c | Client |
capacity | the maximum messages this Client can buffer |
maxItemSize | the max size of a message |
cpuAffinity | cpu affinity mask for this Client's thread |
maxBlockingTime | it is recommended to limit the duration a Client blocks due to no messages to handle, so it can respond to things like Context is stopped, or generate heartbeats if applicable. |
pred | see DeliverPred documentation |
◆ start() [2/2]
template<typename... MessageTuples>
template<typename LoadSharingClientPtrIt , typename DeliverPred = deliverAll>
void hmbdc::app::BlockingContext< MessageTuples >::start |
( |
LoadSharingClientPtrIt |
begin, |
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LoadSharingClientPtrIt |
end, |
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size_t |
capacity = 1024 , |
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size_t |
maxItemSize = max_size_in_tuple< typename std::remove_reference<decltype(**LoadSharingClientPtrIt())>::type::Interests >::value , |
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uint64_t |
cpuAffinity = 0 , |
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time::Duration |
maxBlockingTime = time::Duration::seconds(1) , |
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DeliverPred && |
pred = DeliverPred() |
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) |
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inline |
start a group of clients within the Context that collectively processing messages in a load sharing manner. Each client is powered by a single OS thread
it is ok if a Client is blocking, if its own buffer is not full, it doesn't affect other Client's capabilities of receiving Messages
- Template Parameters
-
LoadSharingClientPtrIt | iterator to a Client pointer |
DeliverPred | a condition functor deciding if a message should be delivered to these Clients, which provides filtering before the Message type filtering. It improves performance in the way it could potentially reduce the unblocking times of threads |
- Parameters
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begin | an iterator, **begin should produce a Client& for the first Client |
end | an end iterator, [begin, end) is the range for Clients |
capacity | the maximum messages this Client can buffer |
maxItemSize | the max size of a message |
cpuAffinity | cpu affinity mask for this Client's thread |
maxBlockingTime | it is recommended to limit the duration a Client blocks due to no messages to handle, so it can respond to things like Context is stopped, or generate heartbeats if applicable. |
pred | see DeliverPred documentation |
◆ stop()
template<typename... MessageTuples>
stop the message dispatching - asynchronously
asynchronously means not garanteed message dispatching stops immidiately after this non-blocking call
◆ trySend()
template<typename... MessageTuples>
template<typename Message >
best effort to send a message to via the BlockingContext
this method is not recommended if more than one recipients are accepting this message since there is no garantee each one will receive it once and only once. this call does not block - return false when deliver doesn't reach all intended recipients This method is threadsafe, which means you can call it anywhere in the code
- Parameters
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m | message |
timeout | return false if cannot deliver in the specified time |
- Returns
- true if send successfully to every intended receiver
◆ trySendInPlace()
template<typename... MessageTuples>
template<typename Message , typename ... Args>
best effort to send a message by directly constructing the message in receiving message queue
since the message only exists after being deleivered, the DeliverPred is not called to decide if it should be delivered this method is not recommended if more than one recipients are accepting this message since it is hard to ensure each message is delivered once and only once. this call does not block - return false when delivery doesn't reach ALL intended recipients This method is threadsafe, which means you can call it anywhere in the code
- Returns
- true if send successfully to every intended receiver
The documentation for this class was generated from the following file: