I/O performance in Node.js worker threads

时光毁灭记忆、已成空白 提交于 2021-02-19 07:17:57
问题 Here's an example with worker thread that takes ~600ms on local machine for synchronous I/O: const fs = require('fs'); const { isMainThread, Worker, parentPort, workerData } = require('worker_threads'); const filename = './foo.txt'; if (isMainThread) { (async () => { console.time('!'); await new Promise((resolve, reject) => { const worker = new Worker(__filename, { workerData: filename }); worker.on('message', resolve); worker.on('error', reject); worker.on('exit', (code) => { if (code !== 0)

How worker threads works in Nodejs?

南楼画角 提交于 2020-04-13 07:17:08
问题 Nodejs can not have a built-in thread API like java and .net do. If threads are added, the nature of the language itself will change. It’s not possible to add threads as a new set of available classes or functions. Nodejs 10.x added worker threads as an experiment and now stable since 12.x. I have gone through the few blogs but did not understand much maybe due to lack of knowledge. How are they different than the threads. 回答1: Worker threads in Javascript are somewhat analogous to WebWorkers

Sleep(suspend) and Resuming windows form starts program on worker thread instead of main thread

孤者浪人 提交于 2019-12-22 12:53:41
问题 The windows form I am working on subscribes to Microsoft.Win32.SystemEvents.PowerModeChanged and on Suspend it runs the Close() method on the form. On Resume it runs the Run() function like it would on initial load. The problem is that when the computer is woken from sleep mode the PowerModeChanged event is triggered on a worker thread named ".Net SystemEvents" and when Run() is called it recreates the form on this worker thread instead of the main thread. This form is a project I inherited

How can I tell if a thread is finished executing without polling ThreadState?

ⅰ亾dé卋堺 提交于 2019-12-21 22:28:46
问题 Is there an elegant way to know when a worker thread is done executing so I can access resources it produced? For example if the worker thread queried a list of SQL Servers using ServersSqlDataSourceEnumerator.Instance.GetDataSources(); and saved the result in a DataTable variable, what mechanism can I use to know when this DataTable variable has been populated/is available. I don't want to poll ThreadState; it would be ideal to fire an event when it's done so I can perform actions with the

Maximizing Worker Thread Utilization

谁说我不能喝 提交于 2019-12-14 02:32:57
问题 To solve a problem (and better my understanding of multitasking) I have written a small thread pool implementation. This thread pool spins up a number of worker threads which pop tasks off of a queue as they are added by the client of the thread pool. For the purposes of this question when the task queue is empty the worker threads are all terminated. After doing some basic benchmarking I have discovered the application spends ~60% of its time waiting to acquire the queue lock. Presumably

Scala, check if Actor has exited

寵の児 提交于 2019-12-13 13:14:22
问题 in Scala 2.8 when I start actors, I can communicate via message passing. This in turn means that I can send the ultimate Exit() message or whatever I decide fits my protocol. But how will I check if an actor has exited? I can easily imagine myself having a task where a master actor starts some worker actors and then simply waits for the answers, each time checking if this was the final answer (i.e. are any Actors still working or did they all exit?). Of course I can let them all send back an

Is it possible to call the main thread from a worker thread in Java?

你离开我真会死。 提交于 2019-12-12 17:34:26
问题 I have a method called action() that deploys three threads. Each deployed thread or worker thread falls into a while loop based on a single instance variable of type boolean being true, for example boolean doWork = true, each thread will have a while(doWork){} loop. When a thread finishes the job will set the doWork to false stopping all the threads from looping. Then I would like to be able to somehow let the main thread recall the action() method to redeploy the threads to do another job.

WCF Service with Worker Thread - how to design?

冷暖自知 提交于 2019-12-11 18:39:43
问题 I have a WCF Service that serves some clients. The design is : WCF Service Layer Business Logic Layer Data Access Layer (LINQ-To-Entities) I need to have a worker thread that does some continuous work on the database (looks for new records, and if finds any - sends information to the client in a 'Push' manner, meaning - the client will be hosting a service so it can receive 'push' notifications from this worker thread). I will host the WCF service on a windows service. Question is : Where do

Effects of uncaught exceptions on threads from Quartz's SimpleThreadPool

戏子无情 提交于 2019-12-11 04:42:40
问题 Using Spring's integration api with Quartz , what will the effects be on cron jobs that have uncaught exceptions? Since the cronbean/worker thread did not catch the exception, will that mean the thread is dead and will not be able to go back to the SimpleThreadPool? If its dead and does not get back to the pool will that mean the SimpleThreadPool will need to create new threads, if say this happens multiple times thus emptying out the pool? This is a sample the stack trace: org

Boost Thread Specific Storage Question (boost/thread/tss.hpp)

一世执手 提交于 2019-12-10 22:02:13
问题 The boost threading library has an abstraction for thread specific (local) storage. I have skimmed over the source code and it seems that the TSS functionality can be used in an application with any existing thread regardless of weather it was created from boost::thread --i.e., this implies that certain callbacks are registered with the kernel to hook in a callback function that may call the destructor of any TSS objects when the thread or process is going out of scope. I have found these