Grpc 線程架構(gòu)
Execute_thrd: 公有線程，啟動(dòng)時(shí)負(fù)責(zé)啟動(dòng)監(jiān)聽，IO，其他任務(wù)；
Timer_thrd：負(fù)責(zé)執(zhí)行指定的定時(shí)任務(wù)（非周期性任務(wù)）；
Consumer_thrd：從Queue中取Event消費(fèi)。
網(wǎng)絡(luò)模型
Thread: 用戶Consumer線程；
Completion_queue: Grpc Queue，用來實(shí)現(xiàn)異步的事件隊(duì)列；
Pollset: 每個(gè)queue有個(gè)對(duì)應(yīng)的pollset，用來從底層收集IO事件；
Polling island : 是pollset的一個(gè)邏輯單位，可以包含多個(gè)pollset；
Epoll set: 底層os對(duì)應(yīng)的epool set，OS內(nèi)核負(fù)責(zé)收活動(dòng)FD，底層epool的封裝（windows giops封裝）
Transport Explainer
在Grpc上的一個(gè)batch，由幾個(gè)基本的stream ops組成。Batch是調(diào)度的基本單位。
Stream ops如下:
send_initial_metadata
Client: initate an RPC
Server: supply response headers
recv_initial_metadata
Client: get response headers
Server: accept an RPC
send_message (zero or more) : send a data buffer
recv_message (zero or more) : receive a data buffer
send_trailing_metadata
Client: half-close indicating that no more messages will be coming
Server: full-close providing final status for the RPC
recv_trailing_metadata: get final status for the RPC
Server extra: This op shouldn't actually be considered complete until the server has also sent trailing metadata to provide the other side with final status
cancel_stream: Attempt to cancel an RPC
collect_stats: Get stats
The fundamental responsibility of the transport is to transform between this internal format and an actual wire format, so the processing of these operations is largely transport-specific.
Transport負(fù)責(zé)內(nèi)部格式和網(wǎng)絡(luò)格式之間轉(zhuǎn)換。
One or more of these ops are grouped into a batch. Applications can start all of a call's ops in a single batch, or they can split them up into multiple batches. Results of each batch are returned asynchronously via a completion queue.
每個(gè)call的ops可以放到一個(gè)batch中，如果一部實(shí)現(xiàn)，會(huì)放到多個(gè)batch中，每一個(gè)batch會(huì)返回completion queue一個(gè)Event。
Internally, we use callbacks to indicate completion. The surface layer creates a callback when starting a new batch and sends it down the filter stack along with the batch. The transport must invoke this callback when the batch is complete, and then the surface layer returns an event to the application via the completion queue. Each batch can have up to 3 callbacks:
recv_initial_metadata_ready (called by the transport when the recv_initial_metadata op is complete)
recv_message_ready (called by the transport when the recv_message op is complete)
on_complete (called by the transport when the entire batch is complete)
上面三個(gè)回調(diào)函數(shù)，肯定會(huì)被執(zhí)行
一個(gè)batch可以分成這三個(gè)階段recv_initial_metadata，recv_message_ready，on_complete。
一個(gè)call的時(shí)序圖：
Client send_initial_metadata: Initiate an RPC with a path (method) and authority
Server recv_initial_metadata: accept an RPC
Client send_message: Supply the input proto for the RPC
Server recv_message: Get the input proto from the RPC
Client send_trailing_metadata: This is a half-close indicating that the client will not be sending any more messages
Server recv_trailing_metadata: The server sees this from the client and knows that it will not get any more messages. This won't complete yet though, as described above.
Server send_initial_metadata, send_message, send_trailing_metadata: A batch can contain multiple ops, and this batch provides the RPC response headers, response content, and status. Note that sending the trailing metadata will also complete the server's receive of trailing metadata.
Client recv_initial_metadata: The number of ops in one side of the batch has no relation with the number of ops on the other side of the batch. In this case, the client is just collecting the response headers.
Client recv_message, recv_trailing_metadata: Get the data response and status
模式處理
服務(wù)器端異步模式框架，添加自定義Event Queue增加并發(fā)性能
