there are many connections, there will be insufficient resources.
Another efficient method is to store a socket connection on the server.And then Round-Robin the list. If a socket port is read (read-only), the corresponding read operation of the socket connection is called.When data is writable on the socket port (write-ready), the corresponding write operation of the socket connection is called. If the socket connection of a port is interrupted, the corresponding destructor is called to close
, directly submit the command + user buffer to the kernel driver, and then return immediately. At this time, the user thread can continue to run and do other things.
When you want to know the command completion status, you can use getqueuedcompletionstatus to obtain the completed request and data.
Therefore, you can submit a large number of IO requests first, and then process and return them slowly.
The reason why iocp is more efficient than epoll is
Basic Application of socket. io tutorial (2) socket. io tutorial
Preface
Socket. IO supports timely, bidirectional, and event-based communication. It can work on every platform, every browser, and every device, with the same reliability and speed.
Real-time analysis: pushes data to clients, which are expressed as real-time counters, charts, or log customers.
Node socket. io event Usage Details, nodesocket. io
The socket. io class library can not only send messages to each other, but also send events to each other through the emit method of the socket port object.
In the previous event, emit said that it was used to manually trigger the event.
Copy codeThe Code is as follows:Socket. emit (event, data, function (data1,
Java BASICS (20) IO streams (3) and java basics io streams
Here are some of the knowledge points and code I summarized in my previous class. Most of the notes I think are very good and classic, sincerely hope that these will help those who want to learn!
It is inconvenient to upload code by module. There are also many things, and they are also clear! If you need it, you can leave your email in the comments.
Http://blog.chinaunix.net/uid-25871104-id-2843472.htmlIO Space and memory spaceSpeaking of this problem, it involves hardware knowledge, X86 system, with two address space: IO Space and memory space, and RISC instruction system CPU (such as ARM, PowerPC, etc.) usually only achieve a physical address space, that is, memory space.Memory Space: Memory address range, 32-bit operating system memory space of 2 of the 32 power, that is, 4G.IO space: A X86-sp
Open file int open (const char *path, int access,int mode)
FILE *fopen (Char *filename, char *mode)
The difference between open and fopen:
The former belongs to low-level IO, the latter is advanced IO.
The former returns a file descriptor, which returns a file pointer.
The former has no buffer, the latter has buffer.
The former is used in conjunction with read, write, etc., the latter with Fread, fwrite a
Objective:
In general operations work often encounter such a scenario, the server's IO load is very high (util in iostat), but unable to quickly locate the IO load source process and source files resulting in the inability to make the appropriate policy to solve the problem.
This phenomenon is more common on MySQL, and before 5.6 (Performance_schema provides IO
Performance Tuning: IO consumption analysis, performance tuning io consumption
Performance Tuning-> how to analyze io consumption
Reprinted please indicate the source: http://blog.csdn.net/supera_li/article/details/45225077For more information about the performance tuning series, see.Performance Optimization: Analysis of CPU consumptionPerformance Optimization:
1, event channel model. The event channel is the prototype of asynchronous IO.2, io mode, one IO call will go through two stages. First, wait for the data phase, the data from the network or disk read to the system kernel (kennel) Two, the data from the kernel copy into the process.Based on these two phases, the Linux system generates five network mode scenarios.
kernel functions)4. Execute the kernel function5. After the kernel function is executed, go to Ret_from_sys_call () routine and return to user space6, the library function implementation in accordance with the return value, and then determine the return value of the library function7, the library function returns, the entire system call completes.4. Buffered io and unbuffered IOUnbuffered IO: Don't be fool
We do some more work for the client's writing. This time we use non-blocking IO to implement the Connect function. int Connect (intconststruct sockaddr *addr, socklen_t Addrlen);Non-blocking IO has the following uses:
1. The process of three handshake is born, and other things are handled.
2. Use this to establish multiple connections at the same time.
3. To implement the Timeout connect fu
Dark Horse programmer-other classes in the IO package and other classes in the io package
Other classes in the IO package:
1. Print stream: provides a printing method to print data of various data types as isByte print stream PrintStreamAcceptable parameter types of constructors:(1) File object(2) String path String(3) Output byte stream OutputStream
Character pr
Java BASICS (12) IO input and output, java basics io Input and OutputI. IO Overview 1. IO concepts
IO: I represents Input; O represents Output.
In Java, IO is input and output based on a stream. AllSerializing data(SAVE) write to
Node. js uses the socket. io method, node. jssocket. io
You can use socket. io to create a socket. io server. However, this server depends on a created http server.
After the http server is running, use the listen method to append a socket. io server to the http server.
Copy
Today, I summarize this point of Io flow, because when I used the IO stream, I knew only a few of the most commonly used IO classes, such as Fileinputstream,bufferedinputstream (buffer stream), etc. But I do not know where it is in the entire IO system, for the whole IO syst
Multithreading programming learning notes-using asynchronous IO (I), multithreading programming io
Multi-thread programming learning notes-using concurrent sets (1)
Multi-thread programming learning notes -- using concurrent sets (2)
Multi-thread programming learning notes-using concurrent sets (3)
In the following scenario, if you run a program on the client, one of the most important tasks is to have a r
Java basics [12] java. io. file (folder) creation, javajava. io. file
Using java. io. file to create a file (folder) is the most basic knowledge of java.
Jdk api description:
You can see the following code:
File file1 = new File ("F:/AAA/BBB/CCC"); if (file1.mkdirs () {System. out. println ("the multilevel folder is created successfully! The created File directo
#include "iospiflash.h"/*******************************************//This was a IOSPI (Simulater by IO)//Lib for Driver Flash W25Q64BV//*******************************************/Sbit ioflashspi_cs= p1^0;Sbit Ioflashspi_din = p1^3;Sbit ioflashspi_dout = p1^4;Sbit ioflashspi_clk = p1^5;/*******************************************//IOSPI Base FUNCData shifting at the--rising edge--of the CLKCLK need a Hold Time Mydelay (3)//ShiftWrite U8Read U8//1Time
I. Update IO stream due to temperature (I) and update io streamIO stream for better understanding (1)
Accumulate and share
Glossary:
Stream
A stream is a continuous input or input by a program.Byte sequence.
Byte stream
Byte streams are composed of bytes and are mainly used to process binary data. More powerful, byte streams can process any data (binary, text, images, audio and video)
What
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