FAQ Database Discussion Community


Can I take advntage of multi core in a multi-threaded application that I develop

c,multithreading,multicore
If I am writing a multi-threaded C application on linux (using pthreads), can I take advantage of multi-core processor. I mean what should an application programmer do to take advantage of multi-core processor. Or is it that the OS alone does so with its various scheduling algorithms...

OpenCV Multi Core Support

opencv,raspberry-pi,multicore,raspberry-pi2
I was wondering if there is multi core support for the OpenCV library. I am experimenting with Haar cascading and it's pretty slow on my Raspberry 2 which would have four cores, but my application is currently running only on a single one. Any ideas?...

Solrcloud multicore configuration

solr,lucene,multicore,sharding,solrcloud
I have a standalone Solr instance with 4 different cores working fine using the embedded Jetty server. I configured the cores for v4.10.3 but since I moved to v5.1 and all seems to work fine without any changes. Before going into production, I need to set it up as a...

Being sure that mpi split work among cores

mpi,multicore
As you know mpi can run a bunch of processes even though there is only one processor with one core. Let's say I have a dual core single processor. If I run a program with mpiexec.mpich -np 2 ./out how can I be sure that the work was split among...

MPI Send latency for different process localities

parallel-processing,mpi,multicore,supercomputers
I am currently participating in a course for efficient programming of supercomputers and multicore processors. Our recent assignment is to measure the latency for the MPI_Send command (thus the time spent sending a zero byte message). Now this alone would not be that hard, but we have to perform our...

How to allocate a task to each processor core?

java,android,encryption,multicore
I am performing basic encryption/decryption on a Quad core android phone. Currently encryption time is 1.45 second per file. For 200 files thats around 5 minutes. I could improve 4 times in performance if I used all 4 cores. for(i=0;i<200;i++) { encrypt(file[i]); } would be a simplified pseudocode, I am...

Operating Systems - Organization Questions

multithreading,operating-system,multicore
I am studying for a 3 topic comprehensive exam that decides If I graduate or not, and have some questions on Operating System Organization A) How does a multicore computer with shared memory differ from a distributed or a clustered system with respect to OS? Make specific reference to the...

How does Thread.currentThread() work when there are multiple processors?

java,multithreading,multicore
Thread.currentThread() can use to get the currently executing thread. And as I think both of the sleep and yield methods are static because they can't execute sleep or yield on other threads. So by making them static it will sleep or yield only the currently executing thread. This seems to...

Are cache-line-ping-pong and false sharing the same?

caching,multicore,computer-architecture,processor,false-sharing
For my bachelor thesis I have to evaluate common problems on multicore systems. In some books I have read about false sharing and in other books about cache-line-ping-pong. The specific problems sound very familiar, so are these the same problems but given other names? Can someone give me names of...

Do concurrency issues in kernel happen when using single core processor?

concurrency,linux-kernel,multicore
When a kernel is compiled on a multicore system, there will be multiple threads or processes operating simultaneously. So, concurrency problem will be an issue. However, when there is only one core in the processor. will it still be a problem?...

Is processor cache flushed during context switch in multicore?

caching,multicore,volatile,flush,context-switch
Recently, I discussed why there is a volatile mark at seq in Java Actors demo @volatile private var seq = 0L private def nextSeq: Long = { val next = seq seq += 1 next } One answer was that threads can be migrated and variables lost (other cores will...

Java 8 automatically using multicore?

java,multithreading,multiprocessing,java-8,multicore
I did some tests a year ago concerning multicore with java 7. First I implemented some calculations only in the main thread (CPU usage showed that only one core did all the work) and then I implemented Callable with an ExecutorService instance. While running it all cores where doing the...