Fastcgi operation principle and PHP FPM parameter configuration

1、 What is? CGI

CGI The full name is “ Public gateway interface ”(Common Gateway Interface),http The server Work with programs on your or other machines “ conversation ” A tool of ,CGI The program must run on the network The server On .

Tradition CGI The main drawback of interface mode is poor performance , Because every time http The server When encountering dynamic programs, you need to restart the script parser to execute parsing , The result is then returned to http The server , When dealing with highly concurrent access , It's almost unavailable , So it was born FastCGI. And the traditional CGI The security of the interface mode is also very poor , It's rarely used now .

2、 What is? FastCGI

FastCGI It's a scalable 、 At high speed http server Interface for communication with dynamic scripting languages （FastCGI Interface in Linux Next is socket, This socket It could be a file socket, It can also be ip socket）, The main advantages are dynamic language and HTTP Server Separate from . Most popular HTTP server All support FastCGI Include Nginx and Lighttpd etc. , meanwhile FastCGI Also supported by many scripting languages , Among them PHP.FastCGI The interface mode is C/S structure , Can be http Separate server and script resolution server , Start one or more script resolution daemons on the script resolution server at the same time . When http Every time the server encounters a dynamic program , It can be delivered directly to FastCGI Process to execute , Then return the result to the browser . This way we can make http The server specifically processes static requests or returns the results of the dynamic script server to the client , This greatly improves the performance of the whole application system .

3、Nginx Next FastCGI Operation principle

Nginx It does not support direct calling or parsing of external programs , All external procedures （ Include PHP） Must pass FastCGI Interface to call .FastCGI Interface in Linux Next is socket（ This socket It could be a file socket, It can also be IP socket）. In order to call CGI Program , I need one more FastCGI Of wrapper（wrapper It can be understood as a program used to start another program ）, This wrapper Bind to a fixed socket On , Like ports or files socket. When Nginx take CGI Request sent to this socket When , adopt FastCGI Interface ,wrapper Accept the request , Then spawn a new thread , This thread calls the interpreter or external program to process the script and read the return data , next ,wrapper Then pass the returned data through FastCGI Interface , Along the fixed socket Pass to Nginx, Last Nginx Send the returned data to the client , This is it. Nginx+FastCGI The whole process of operation .

4、 Optimize php-fpm Process management configuration parameters .

php-fpm Compiler parameters for ：

php5.3 And above versions, the compilation parameters are ”--enable-fpm”

php5.2 And the following version compilation parameters are ”--enable-fastcgi  --enable-fpm  --enable-force-cgi”

#php-fpm.conf Profile parameter optimization options .

pm.max_children = 1024      # Maximum number of subprocesses

pm.start_servers = 16        # Number of processes at startup  

# Ensure that the minimum number of idle processes , If the idle process is less than this value , Create a new subprocess

pm.min_spare_servers = 5     

# Maximum number of idle processes guaranteed , If the idle process is greater than this value , Then clean up

pm.max_spare_servers = 20

# Timeout for process

pm.process_idle_timeout = 15s 

# Set the maximum number of requests processed by each child process

pm.max_requests = 1000

# Set the rlimit Limit

rlimit_files = 1024

# When a request for this setting timeout , It will correspond to PHP Call stack information is fully written to the slow log . Set to '0' Express 'Off'

request_slowlog_timeout = 10s

# Logging of slow requests , coordination request_slowlog_timeout Use

slowlog = log/$pool.log.slow