volatile only forces your code to re-read the value, it cannot control where the value is read from. If the value was recently read by your code then it will probably be in cache, in which case volatile will force it to be re-read from cache, NOT from memory. There are not a lot of … Read more
Inherently sequential. Example: The number of women will not reduce the length of pregnancy.
Yes, see the parallel package: ls `using` parList rdeepseq will evaluate each element of the list in parallel via the rdeepseq strategy. Note the use of parListChunk with a good chunk value might give better performance if your elements are too cheap to get a benefit evaluating each one in parallel (because it saves on … Read more
Run the ‘top‘ command and press ‘1‘ to see the individual cores.
Consider the following program: import java.util.ArrayList; import java.util.List; public class Foo { public static void main(String… args) { List<Integer> list = new ArrayList<>(); for (int i = 0; i < 1000; i++) { list.add(i); } list.stream().forEach(System.out::println); } } You will notice that this program will output the numbers from 0 to 999 sequentially, in the … Read more
I’m the one who was working on this Summer of Code project. The patches have been sent to Duncan, but he hasn’t reviewed them yet. Note that my code works at the package granularity, so you won’t get any speedup when building a single package. I’m currently working on a parallel wrapper around ghc –make, … Read more
First, try to understand the concept of ‘process’ and ‘thread’. A thread is a basic unit for execution: a thread is scheduled by operating system and executed by CPU. A process is a sort of container that holds multiple threads. Yes, either multi-processing or multi-threading is for parallel processing. More precisely, to exploit thread-level parallelism. … Read more
Multi-core programming may actually require more than one paradigm. Some current contenders are: MapReduce. This works well where a problem can be easily decomposed into parallel chunks. Nested Data Parallelism. This is similar to MapReduce, but actually supports recursive decomposition of a problem, even when the recursive chunks are of irregular size. Look for NDP … Read more
Edit – I modified the script to optionally display the output of each process Here is a native batch solution that reliably runs a list of commands in parallel, never launching more than n processes at a time. It even has a mechanism built in to distribute the processes to specific CPUs or remote machines … Read more