worker_threads.pdf

Transcript

1. Worker Threads Tamar Twena-Stern
2. Tamar Twena-Stern • Software Engineer - manager and architect • Backend Manager @XM Cyber • Was a CTO of my own startup • Passionate about Node.js ! • Twitter: @SternTwena
3. Tamar Twena-Stern • On Maternity Leave • Have 3 kids • Loves to play my violin • Javascript Israel community leader
4. Introduction
5. Traditional Approach - Blocking IO Client Server Thread Thread Thread Request Request Request
6. Problems •The system allocates CPU and memory resources for every new thread •When the system is stressed – overhead of thread scheduling and context switching •The system waste resources for allocating threads instead of doing actual work
7. Node.js Architecture
8. Node.js Architecture - High Level
9. • One Process • One Thread • One Event Loop • One JS Engine Instance • One Node.js Instance Node.js Process
10. Demo - CPU Intensive Operation
11. Lets Deep Dive Into The CPU Intensive Problem
12. Blocking & Non Blocking Functions • Blocking Function - Main event loop must wait until it has finished to execute the next command. • Non-Blocking Function - • Main event loop will continue as soon as the function begins • Alerts the main loop once it has finished by calling a “callback”.
13. Why CPU Intensive Operations Don’t Shine In Node • Non Blocking IO + Event Loop • Constant amount of threads • CPU Intensive operation will block the event loop • CPU intensive operation that will be off loaded to the worker thread pool will make one of the threads busy for long
14. CPU Intensive Operations Synchrones Operations
15. Brilliant Idea :Let’s Add Threads To Node.js Core !
16. Why It Will Not Work ? • Theoretically simple - add Libraries to Node core to enable threads • Adding threads will change the nature of JavaScript • No synchronise mechanism • JavaScript basic types are not atomic, for example numerics
17. Worker Threads
18. Worker Threads - Definition • Applications use multiple isolated JavaScript workers • Main worker and child workers • Communication provided by Node.js • Separate instances of V8 and Event Loop • Shared memory
19. Worker Threads - Components • One process • Multiple threads • One event loop per thread • One JS Engine Instance per thread • One Node.js Instance per thread
20. From One Process To Worker Threads
21. How Is It Work ? • Worker executes a script provided by the parent worker • The worker runs in Isolation from other workers • Ability to pass messages between the worker and the parent • Parallelism - V8 Isolate
22. How Is It Work ?
23. Demo - CPU Intensive Operations With Worker Threads
24. Why The Improvement Is Not Enough ?
25. Our Mistake : Opening Worker On Each Request
26. Guidelines For Writing Production Worker Threads Applications : • For production - use worker threads pool • If you can - use asynchronous operations, it is much faster • Don’t use Worker Thread for IO operations - Node.js built in mechanisms are much faster
27. Demo - Creating Worker Threads Pool
28. • Twitter: @SternTwena