30
votes
A multi-threaded Producer Consumer with C++11
Prefer Reference over Pointer
Since the producer and consumer must have a buffer you should pass it by reference (rather than pointer). This also makes sure there is no confusion over ownership of ...
- 91.7k
24
votes
AsyncDictionary - Can you break thread safety?
The reason why there is no async API for a dictionary is, that all operations on a dictionary are so fast, that there is no need for asynchronicity.
For concurrent scenarios there is the thread safe ...
- 8,498
21
votes
Accepted
Voxel World Optimization
To solve this problem, I made each Voxel aware of its neighbours, this was achieved in the world generation/height-map loading phase.
Then I was able to change the optimization algorithm to the ...
- 376
16
votes
A multi-threaded Producer Consumer with C++11
I have a few comments about your code:
Using std::lock_guard is great to handle mutexes since it automatically unlocks the acquired mutex when leaving the scope. ...
- 19.9k
15
votes
Send email just once per day
Couple of remarks:
IsSent() smells like a property, not a method. It should be more descriptive as well: what object are you calling this on? It seems to indicate ...
- 11.5k
14
votes
Accepted
Using Java 8 parallel streams
Your code is not thread-safe. Each of the threads will, in parallel, be accessing both the best, and the bestQuality variables.
...
- 96.7k
14
votes
Accepted
Hybrid Lock Implementation
I would expect the standard library's mutex (which is basically pthread_mutex) to already take care of this optimization behind ...
- 19.1k
13
votes
AsyncDictionary - Can you break thread safety?
Threading Design
Your implementation has a very intrusive lock for all read and write operations, using the SemaphoreSlim with max concurrency 1.
...
- 13.8k
12
votes
Accepted
Simple Implementation of a ReentrantLock
Your code looks sensible, with two exceptions, the unlock should only notify when the lock is unlocked.... your code currently allows for asymmetrical notifications (excessive notifications).
...
- 96.7k
12
votes
AsyncDictionary - Can you break thread safety?
It's pretty hard to break something that uses a global lock around everything. So this seems pretty thread-safe. But that doesn't answer the question of why you'd want to use this.
Asynchronous ...
- 525
11
votes
Accepted
11
votes
Accepted
Printing even and odd using two concurrent threads
public class Odd implements Runnable{
private Monitor sharedObject;
public Odd(Monitor monitor){
this.sharedObject = monitor;
}
You implemented the class as ...
- 5,174
11
votes
Accepted
A buffer that holds and provides the latest n items
Naming
There is one 'u' in ConcuurentCircularBuffer that wants to be a 'r' --> ConcurrentCircularBuffer
There is no need to abbreviate name like size (sz --> ...
- 8,498
11
votes
Accepted
Parallelized for loop in Bash
Some suggestions:
The trailing slash in the mkdir command is redundant.
$(…) is preferred over backticks for command ...
- 8,737
10
votes
Send email just once per day
Normally, you don't catch Exceptions to throw them again, it doesn't make sense, let them rise up, don't catch them here, I don't think it is your intention to stop the exceptions here, so don't.
...
- 28.5k
10
votes
Accepted
Concurrent Linked Hash Set
There are several thread safety issues :
if size(), remove() and removeAll() need to ...
- 5,359
10
votes
A buffer that holds and provides the latest n items
In addition to @JanDotNet's answer:
You can use "less strict" lock in your code, specifically ReaderWriterLock or ...
- 748
10
votes
Accepted
RabbitMQ wrapper to work in a concurrent environment
A few things that caught my eye:
So called dispose pattern only makes sense if you implement a finalizer on your base class or on one of its descendants. If you do ...
- 13k
10
votes
Accepted
A portable parallel loop construct in C89
The code for apple and linux cases is identical (except one case). Consider
#if defined(__APPLE__) || defined(__linux__)
#define POSIX
#endif
and consolidate the ...
- 53.4k
9
votes
Accepted
Concurrent LRU cache using sychronizedMap() or ReadWriteLock
My experience with variants on the java.util.concurrent.locks.* classes suggests that their sweet spot in terms of performance is when the work to be done is ...
- 96.7k
9
votes
Accepted
Caching Color-Bitmaps as MemoryStreams
First I'm not a fan of recycling IDs. Too much confusion can happen. For example Thread 1 adds a Dog Image and gets ID 1. Thread 2 calls ReleaseAllImages and then adds a Cat image and gets ID 1. ...
- 4,096
9
votes
Accepted
AsyncDictionary - Can you break thread safety?
If you modify the AsyncDictionary while enumerating its keys/values it throws InvalidOperationException (if the backing ...
- 2,864
8
votes
A buffer that holds and provides the latest n items
You can make your code much simpler if you use a LinkedList<T> instead of an array. It has also a much better performance when inserting and removing items in ...
- 43.8k
7
votes
Using Java 8 parallel streams
http://docs.oracle.com/javase/8/docs/api/java/util/stream/Stream.html#max-java.util.Comparator-
Returns the maximum element of this stream according to the provided Comparator. This is a special ...
7
votes
Send email just once per day
you should be using a couple of using statements in your code, then you can get rid of the try/finally statement completely because the closing/disposing of the ...
- 28.5k
7
votes
Parallel "wget" in Java
Just a rant, someone else will do the real work, but for me it's hard to read.
durl = url;
When I see it..... what to say?
So slowly... "url" is fine, everybody ...
- 13.4k
7
votes
Threadsafe HashMap with snapshot support
There are a number of things that I think you have completely overengineered.
Holder
This can be replaced with Optional
SingleSnapshotMap
This class exposes 4 ...
- 96.7k
7
votes
Accepted
Solving a race condition
Concurrency Strategy
In general, using volatile is complicated, partially because the meaning of volatile changed in Java 1.4, ...
- 96.7k
Only top scored, non community-wiki answers of a minimum length are eligible