Multi-threading related questions including technique, structure, and safety issues.

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2answers
99 views

Lock threads or not lock threads?

I have an application (full-stack) that is used millions of times concurrently. Some vital application properties are managed on the client side (at the time it seemed to be the simplest approach to ...
10
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1answer
142 views

Do classes in a JRE library support observable and/or asynchronous reads from external/non-JRE assemblies?

How can I implement my cross-platform library (e.g. on JRE) to operate in a thread-safe manner on object references, so that native front-ends on other platforms can observe the object and take ...
4
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1answer
141 views

Evaluating concurrent application design approaches on Linux

Working on relatively low-speed hardware, I need to grab a snapshot of a rapidly changing datastream and then post-process the snapshot data and save it to disk. I need help with designing the ...
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1answer
337 views

Alternatives to Pessimistic Locking in Cluster Applications

I am researching alternatives to database-level pessimistic locking to achieve transaction isolation in a cluster of Java applications going against the same database. Synchronizing concurrent access ...
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1answer
53 views

ThreadPool.QueueUserWorkItem is this example a valid use case?

I need to send out a batch of reminder emails, never more than 100 emails per batch, using authenticated SMTP. This is happening on a WindowsService (no GUI). The SMTP library we're using raises a ...
0
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1answer
365 views

Android, using a Fragment to hold/edit complex object, accesible from any Activity

I'll do my best to describe the problem, but I'm still very new to several concepts that I think this problem requires to be solved (namely interfaces and threads). I should preface this by saying ...
-1
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1answer
83 views

What's the best way to implement a real time show board to show results from concurrent result producers in Java?

I'm making a load test tool that launches multiple thread to simulate load on the target server. Each thread executes a predefined set of commands in the structure of TestSuite - TestCase- TestStep ...
5
votes
0answers
285 views

How can I make a universal construction more efficient?

A "universal construction" is a wrapper class for a sequential object that enables it to be linearized (a strong consistency condition for concurrent objects). For instance, here's an adapted ...
2
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0answers
45 views

ODBC 3 Multiple Statements vs Multiple Connections

So right now I have a single thread to handle all the requests for the database. Let's say I have 400 requests per second for logins / logouts / other stuff, and 400 requests per second which are only ...
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0answers
87 views

Better choice of Queue then a ConcurrentLinkedQueue if I have low number of threads in Java

I have two threads, one that is reading messages from the web and putting them into some sort of a queue. The other is suppose to read it. I looked into a ConcurrentLinkedQueue and it looks good for ...
1
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0answers
93 views

Terminology - Difference between thread and process and how they manage DB connections

I've been working more with concurrency in Ruby recently, and I keep seeing various articles using "threads" and "process" interchangeably. What are the actual definitions of these terms? Is a ...
1
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0answers
42 views

Cost of cache coherency/sharing data across multiple cores?

If I have two CPU cores, one is writing a particular cache line and the other core wishes to Read Write the same cache line, what are the costs (in cycles) for doing so? I am a little unsure ...
1
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0answers
156 views

Threading strategies for a webservice implementation

If I am building a webservice/Web API for servicing requests, there are 2 threading strategies I can think of. I will explain this in terms of Java (though the question may be relevant for any other ...
1
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0answers
235 views

Android: How to set a stop flag in native C thread from Java

In my NDK Android app, Java part runs native C code to perform intensive calculations. It does so by creating an AsyncTask worker object that runs the native code in a separate thread via the JNI. The ...
1
vote
0answers
91 views

Concurrent directory-tree search

I am trying to get familiar with concurrent programming, and have picked up an excercise to use a fixed number of threads that search through a directory structure. This is pretty much the way it is ...
1
vote
0answers
154 views

Using Singletons in JS with workers

I'm building a javascript application that does continuous drawing, but relies on asynchronous scripts in the background which also need to poll for events and write to "global variables". This got me ...
1
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0answers
1k views

Best method for async initialization of view model in MVVM pattern (WPF)

I'm working on a business application (C#, WPF, EF, MVVM). I need to load a bunch of items from database, create view models for them and put them in a window. Is there a way to create the view model ...
1
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0answers
110 views

Thread safety IDE warnings

I wonder, would it not be possible for an IDE to detect any shared mutable objects that are used in multiple threads? You could flag types as either [ThreadSafe] or [Immutable] using attributes in ...
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0answers
73 views

What to use in case of waiting for something that is complete: delegates, events and/or thread

I try to give a concrete example. Create a semaphore for a crossroads. I have two semaphores. I have possibility to set a duration of semaphore 2 minutes, 5 minutes, 10m inutes etc. When one ...
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0answers
45 views

Merging waitable objects

Lets say you have two (or more) objects from which both allow a thread to wait for an event to occur. Foo.Wait(timeout); Bar.Wait(timeout); The main thread wants to wake up when either of these ...
0
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0answers
105 views

Java Multi-threading

I was solving this question in Java where the user enters a partitioned array. The computer then determines what all elements from that array can be used as pivots. (Pivots are the same pivots that ...
0
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0answers
60 views

How to prevent parallel calls to model?

While there is some command running which calls methods on some model, how to prevent concurrent calls for critical places in that model? If multiple requests comes in then they should maintain their ...
0
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0answers
206 views

Is it possible to have multiple threads using Background Workers for different controls within one GUI

In my current project i have a CPU intensive 3D chart that needs to be updated in real time. I have been using background workers for the project and using those, i do all the processing in the ...
0
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0answers
339 views

How is CancellationToken.IsCancellationRequested updated?

I've been doing some refactoring today and I encountered one interesting thing. I've extracted a method from a code which uses a cancellation token passed to it in order to check if the user did not ...
0
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0answers
1k views

Java write to text file from multiple threads

I have a thread which read and insert new lines in same file. I must synchronized that file so that no other thread is not accessing the file at the same time. Here is how i will synchronize a file ...
0
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0answers
100 views

Primes and multi-threading

I use to compute primes using linear code which took a long time. As I've an 8 cores processor I thought about multi-threading. At first I use to put a huge number of int in a vector then share the ...
0
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0answers
767 views

Make a java program use more processors

I am running a program that is supposed to solve a problem with the brute force approach. My computer has a quad-core CPU. When I run the program clearly java uses only one core, because in my ...
0
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0answers
427 views

Managing child worker thread list

After so much research, I thought I should ask the experts. I am working on a project for my corporate employer, we have android and iPhone mobile apps that make request to a web service, the request ...
0
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0answers
121 views

Why user threads are mapped to Kernel threads

Since user threads are mapped to kernel threads, why don't we create all threads as kernel threads that is a process with zero user thread. Doesn't mapping of user thread to kernel thread create ...