Preemptive multitasking using coroutines in PHP Swoole

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Preemptive multitasking using coroutines in PHP Swoole Bruce Dou | @doubaokun [email protected] 6th Jun 2019

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1. Evolution of web server or services 2. The problems to solve for PHP 3. Coroutinesand preemptive schedulingfor PHP 4. Show case preemptivescheduling in PHP Swoole Agenda

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About me • Software Architect & Head of Development • Founderat Transfon • Twitter:@doubaokun • Email:[email protected] • Linkedin:linkedin.com/in/brucedou • Github: github.com/doubaokun

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Security Performance Regulation compliance Cost control About Transfon

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Evolution of web server or services

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https://unixism.net/2019/04/linux-applications-performance-introduction/

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I/O bound vs CPU bound

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Decoupling I/O and Computation

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Async and non-blocking I/O

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Why non-blocking I/O matters Multiple cores and fast CPU vs slow Network I/O

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Linux I/O multiplexing, non-blocking • select() monitors the sockets’ status flag and return the status of all sockets, manually iterate through all the fds (C10K problem) • poll() similar to select() but allocate an array of pollfd, can handle more than 1024 sockets •epoll() monitors sockets’ status and trigger related events, and only return triggered events array.

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Reactor pattern

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PHP ?

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The problems to solve for PHP • High concurrency,large numberof connections • Long-liveconnections,real-timeservices • Long-liveconnectionsto DB, Cache, RPC etc • Supportmoreprotocols • Server programming,not just scripts • Milliseconds scheduler • Async tasks of consuming3rd party services • Manage and reuse the statusin memory • Performance

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1.Receive the request 2.Load and compile PHP files and codes 3.Initialize the context objects and variables 4.Execute the functions 5.Send the response 6.Recycle the resources The life cycle of HTTP request in PHP-FPM

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1.Load and compile files and codes 2.Initialize the context objects and variables 3.Receive the request 4.Execute the functions 5.Send the response 6.Recycle the resources The life cycle of HTTP request in PHP Swoole

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PHP Swoole https://www.swoole.co.uk/ https://github.com/swoole/swoole-src @php_swoole Coroutine-based concurrency library for PHP

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Get started git clone [email protected]:doubaokun/phplondon201906.git docker build -f Dockerfile -t swoole-phplondon . docker run --rm -p 9501:9501 -v $(pwd):/app -w /app \ swoole-phplondon server.php

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How it looks like

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How fast

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Open Source(Apache2 license) PHP Extension C/C++ / Boost.Context Callbackstyle & Coroutine Event-basednon-blockingI/O HTTP/HTTP2/Websocket/TCP/UDPetc Milliseconds task scheduler Process manager Preemptivescheduling PHP Swoole

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The problems we like to solve further • Callback hell • Use Coroutinestyle (sync) concurrency • Automaticallycontextswitchbasedon I/O • Soft real-time • Long tail latency • One bad guy stopthe world

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Callback hell

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Callback hell Swoole 2.x.x

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I/O based automatically scheduling in PHP Swoole

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I/O based automatically scheduling

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Coroutines in PHP Swoole

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Coroutines in PHP Swoole

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Problem with CPU heavy business logics

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Preemptive scheduling

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PHP Swoole Server

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HTTP server with PHP Swoole

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HTTP server structure

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Preemptive scheduling in PHP Swoole Server

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Scheduling thread ZendVM:EG(vm_interrupt)= 1 Zend_interrupt_function Yield current coroutineif it runs longer than 5ms How preemptive scheduling works

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Preemptive scheduling in PHP Swoole Server

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HTTP server structure single process

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Preemptive scheduling in PHP Swoole Server time curl -I http://127.0.0.1:9501/\?p\=1 (CPU heavy logics) time curl -I http://127.0.0.1:9501/\?p\=0 (light weight logics) docker run --rm -p 9501:9501 -v $(pwd):/app -w /app \ swoole-phplondon server_preemptive.php time curl -I http://127.0.0.1:9501/\?p\=1 & sleep 1 && \ time curl -I http://127.0.0.1:9501/\?p\=0 & wait

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Preemptive scheduling in PHP Swoole Server ini_set("swoole.enable_preemptive_scheduler", "0");

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Preemptive scheduling in PHP Swoole Server ini_set("swoole.enable_preemptive_scheduler", "1");

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Real world meaningof preemptive scheduling

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Real-world meaning of preemptive scheduling

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https://github.com/doubaokun/phplondon201906 https://www.swoole.co.uk/ https://github.com/swoole/swoole-src https://swoole.slack.com https://twitter.com/php_swoole Thank you