Конференция: https://podlodka.io/fecrew Автор: https://github.com/tshemsedinov Youtube: https://youtube.com/TimurShemsedinov

2. Processes

3. Processes
Threads

4. Processes
Threads
Asynchronicity

5. javascruptissinglethreaded

6. nodejsissinglethreaded

7. Node.js Event Loop

8. youtu.be/8aGhZQkoFbQ

9. Concurrency in Node.js
● Processes
● Threads
● Asynchronous programming

10. holyjs-moscow.ru/talks/multicore-javascript-past-present-and-future/

11. Concurrency in Node.js
● Processes: child_process
cluster
● Threads: C++ threads
worker_threads
WASM threads
● Asynchronous programming:
Tons of abstractions

12. Concurrency in Node.js
● Processes: child_process (posix fork)
cluster
● Threads: C++ threads
worker_threads
WASM threads
● Asynchronous programming
Tons of abstractions

13. Concurrency in Node.js
● Processes: child_process (posix fork)
cluster (legacy wrapper for child_process)
● Threads: C++ threads
worker_threads
WASM threads
● Asynchronous programming
Tons of abstractions

14. Concurrency in Node.js
● Processes: child_process (posix fork)
cluster (legacy wrapper for child_process)
● Threads: C++ threads
worker_threads
WASM threads
● Asynchronous programming
Tons of abstractions

15. Concurrency in Node.js
● Processes: child_process (posix fork)
cluster (legacy wrapper for child_process)
● Threads: C++ threads (v8 & libuv pool, addons)
worker_threads
WASM threads
● Asynchronous programming
Tons of abstractions

16. Concurrency in Node.js
● Processes: child_process (posix fork)
cluster (legacy wrapper for child_process)
● Threads: C++ threads (v8 & libuv pool, addons)
worker_threads (userspace multithreading)
WASM threads
● Asynchronous programming
Tons of abstractions

17. youtu.be/pO5a10YPQG4

18. Concurrency in Node.js
● Processes: child_process (posix fork)
cluster (legacy wrapper for child_process)
● Threads: C++ threads (v8 & libuv pool, addons)
worker_threads (userspace multithreading)
WASM threads (userspace multithreading)
● Asynchronous programming
Tons of abstractions

19. Concurrency in Node.js
● Processes: child_process (posix fork)
cluster (legacy wrapper for child_process)
● Threads: C++ threads (v8 & libuv pool, addons)
worker_threads (userspace multithreading)
WASM threads (userspace multithreading)
● Asynchronous programming (single-threaded)
Tons of abstractions

20. Concurrency in Node.js
● Processes: child_process (posix fork)
cluster (legacy wrapper for child_process)
● Threads: C++ threads (v8 & libuv pool, addons)
worker_threads (userspace multithreading)
WASM threads (userspace multithreading)
● Asynchronous programming (single-threaded)
Tons of abstractions: cb, event, promise, async...

21. callbacks

22. callbacks
event

23. callbacks
event
emitter

24. callbacks
event
emitter
generator

25. callbacks
thenable
event
emitter
generator

26. callbacks
thenable
event
emitter
observer
generator

27. callbacks
thenable
promise
event
emitter
observer
generator

28. callbacks
thenable
promise
event
emitter
observer
generator deferred

29. callbacks
thenable
promise
event
emitter
observer
future
generator deferred

30. callbacks
thenable
promise
event
emitter
observer
future
generator
async
generator
deferred

31. callbacks
thenable
promise
event
emitter
observer
Rx
future
generator
async
generator
deferred

32. callbacks
thenable
promise
async/await
event
emitter
observer
Rx
future
generator
async
generator
deferred

33. callbacks
thenable
promise
async/await
event
emitter
observer
Rx
future
generator
async
generator
deferred
collector

34. callbacks
thenable
promise
async/await
event
emitter
observer
Rx
future
generator
async
generator
async
queue
deferred
collector

35. callbacks
thenable
promise
async/await
event
emitter
observer
Rx
future
async
iterator
generator
async
generator
async
queue
deferred
collector

36. callbacks
thenable
promise
async/await
event
emitter
observer
Rx
future
async
iterator
generator
async
generator
async
queue
deferred
locks
collector

37. youtu.be/VdRhAXnfrd0

38. habr.com/ru/post/452974

39. Concurrency in Node.js
● Processes: child_process (posix fork)
cluster (legacy wrapper for child_process)
● Threads: C++ threads (v8 & libuv pool, addons)
worker_threads (userspace multithreading)
WASM threads (userspace multithreading)
● Asynchronous programming (single-threaded)
Tons of abstractions: cb, event, promise, async...

40. youtu.be/GRb-XQ5JRA8

41. web.dev/webassembly-threads

42. How can we use worker_threads?
● Atomics (for CAS - compare-and-swap)
● Shared memory (SharedArrayBuffer)
● Parallel programming primitives
● Async/await as a syntax for parallel primitives

43. youtu.be/KNsm_iIQt7U

44. Concurrency Problems
● Race condition
● Deadlock
● Livelock
● Resource starvation
● Resource leaks

45. slideshare.net/tshemsedinov/how-are-race-conditions-in-single-threaded-javascript-possible

46. Approaches for Concurrency
● Synchronization primitives
● Special control flow organization
● Queuing theory
● Shared memory with OpenMP
● Actor model (message passing)
● Use DBMS transactions
● Specialized data structures

47. Synchronization Primitives
● Semaphore
● Binary semaphore
● Counting semaphore
● Condition variable
● Spinlock
● Mutex (and locks)
● Timed mutex
● Shared mutex
● Recursive mutex
● Monitor
● Barrier

48. youtu.be/auMM-uV12F0

49. Web Locks API example
(async () => {
await something();
await locks.request('resource', async lock => {
// critical section for `resource`
});
await somethingElse();
})();

50. Node.js performance measurement APIs
● perf_hooks
eventLoopUtilization
Added in: v14.10.0, v12.19.0
● worker.performance
eventLoopUtilization
Added in: v15.1.0, v14.17.0, v12.22.0

51. Node.js performance measurement APIs
eventLoopUtilization([elu1[, elu1]]): elu;
interface EventLoopUtilization {
idle: number;
active: number;
utilization: number;
}

52. youtu.be/qipIRQptP_4

53. Library: npm i noroutine
const noroutine = require('noroutine');
const module1 = require('./module1.js');
const module2 = require('./module2.js);
noroutine.init({ modules: [module1, module2] });
(async () => {
const res1 = await module1.method1('value1');
const res2 = await module2.method2('value2');
console.log({ res1, res2 });
})();

54. Node.js I/O concurrency model
Main
thread
Thread
Pool
Task Balancer
module 1
module 2
...
module M
module 1
module 2
...
module M
module 1
module 2
...
module M
module 1
module 2
...
module M

55. Node.js I/O concurrency model
Main
thread
Thread
Pool
Task Balancer
module 1
module 2
...
module M
module 1
module 2
...
module M
module 1
module 2
...
module M
module 1
module 2
...
module M
Shared Memory

56. slideshare.net/tshemsedinov/nodejs-threads-for-iobound-tasks

57. Aspects of parallel/distributed systems
● Consistency
■ Atomicity, Consistency, Isolation, Durability
■ Basically available, Soft-state, Eventually consistent
● Availability
■ Always, netsplit supported
● Partition tolerance
■ Scalability, partitioning, sharding, replications

58. Brewer's theorem
● Consistency + Availability
Classic ACID DBMS: PG, Oracle, DB2
● Consistency + Partition tolerance
Redis, Hbase, MongoDB
● Availability + Partition tolerance
DynamoDB, Riak, Cassandra

59. Other approaches
● MapReduce
● Lock-free Data Structures
● CRDT (Conflict-free Replicated Data Types)
● Byzantine generals (Byzantine fault)
● Patch-based, Paxos, Consensus protocols
● Immutable approach, statefull vs stateless
● CQRS, EventSourcing

60. Scale
with threads

61. youtu.be/PHyl4b8Fj5A

62. Lectures
Node.js free lectures
github.com/HowProgrammingWorks/Index/blob/master/Courses/NodeJS.md
Asynchronous programming
github.com/HowProgrammingWorks/Index/blob/master/Courses/Asynchronous.md
All lectures index
github.com/HowProgrammingWorks/Index

63. All public talks
Talks index
github.com/HowProgrammingWorks/Index/blob/master/Courses/Talks.md
Metarhia presentation
youtu.be/PHyl4b8Fj5A
Node.js in 2021
youtu.be/nnB7ADYso8s

64. Links
Github
github.com/tshemsedinov
Youtube
youtube.com/TimurShemsedinov
Telegram
github.com/HowProgrammingWorks/Index/blob/master/Links.md