digitalmars.D.learn - Looking for command for synchronization of threads
- Sparsh Mittal (12/12) Jan 30 2013 Background:
- Sean Kelly (12/17) Jan 30 2013 algorithm iteratively updates a matrix (2D grid) of data. So, I will =
- Sparsh Mittal (29/33) Jan 30 2013 Thanks. I wrote this:
- FG (30/34) Jan 31 2013 Barrier doesn't release because you've only called wait() from one threa...
- Sparsh Mittal (2/2) Jan 31 2013 Thank you very much for the code. It works fine and is extremely
- qznc (5/18) Jan 31 2013 You could look at this Rosetta Code snippet, which does something
Background: I am implementing an iterative algorithm in parallel manner. The algorithm iteratively updates a matrix (2D grid) of data. So, I will "divide" the grid to different threads, which will work on it for single iteration. After each iteration, all threads should wait since next iteration depends on previous iteration. My issue: To achieve synchronization, I am looking for an equivalent of sync in Cilk or cudaEventSynchronize in CUDA. I saw "synchronized", but was not sure, if that is the answer. Please help me. I will put that command at end of "for" loop and it will be executed once per iteration.
Jan 30 2013
On Jan 30, 2013, at 2:58 PM, Sparsh Mittal <sparsh0mittal gmail.com> = wrote:Background: I am implementing an iterative algorithm in parallel manner. The =algorithm iteratively updates a matrix (2D grid) of data. So, I will = "divide" the grid to different threads, which will work on it for single = iteration. After each iteration, all threads should wait since next = iteration depends on previous iteration.=20 My issue: To achieve synchronization, I am looking for an equivalent of sync in =Cilk or cudaEventSynchronize in CUDA. I saw "synchronized", but was not = sure, if that is the answer. Please help me. I will put that command at = end of "for" loop and it will be executed once per iteration. I suggest looking at std.parallelism since it's designed for this kind = of thing. That aside, all traditional synchronization methods are in = core.sync. The equivalent of "sync" in Cylk would be core.sync.barrier.=
Jan 30 2013
I suggest looking at std.parallelism since it's designed for this kind of thing. That aside, all traditional synchronization methods are in core.sync. The equivalent of "sync" in Cylk would be core.sync.barrier.Thanks. I wrote this: import std.stdio; import std.concurrency; import std.algorithm; import core.sync.barrier; import core.thread; void sorter(Tid owner, shared(int)[] sliceToSort, int mynumber) { writefln("Came inside %s", mynumber); sort(sliceToSort); writefln("Going out of %s", mynumber); } void main() { shared numbers = [ 6, 5, 4, 3, 2, 1 ]; auto barrier = new Barrier(2); spawn(&sorter, thisTid, numbers[0 .. $ / 2], 0); spawn(&sorter, thisTid, numbers[$ / 2 .. $],1 ); writefln("Waiting for barrier in main"); barrier.wait(); writeln(numbers); } It compiles but barrier does not get released. Can you please point out the fault. Pardon my mistake. I searched whole web, there are almost no examples of it online. I saw this: http://www.digitalmars.com/d/archives/digitalmars/D/bugs/Issue_9005_New_std.concurrency.spawn_should_allow_void_delegate_Args_shared_for_new_Tid_44426.html but it does not compile.
Jan 30 2013
On 2013-01-31 03:29, Sparsh Mittal wrote:Thanks. I wrote this: [...] It compiles but barrier does not get released. Can you please point out the fault. Pardon my mistake. I searched whole web, there are almost no examples of it online.Barrier doesn't release because you've only called wait() from one thread, while initializing the Barrier to use two threads. The following code works for me. Notice that the Barrier and wait() are used in 3 threads. But better have this verified by someone who had done more threading in D. :) import std.stdio; import std.concurrency; import std.algorithm; import core.sync.barrier; import core.thread; __gshared Barrier barrier = null; void sorter(Tid owner, shared(int)[] sliceToSort, int mynumber) { writefln("Came inside %s", mynumber); sort(sliceToSort); writefln("Going out of %s", mynumber); barrier.wait(); } void main() { shared numbers = [ 6, 5, 4, 3, 2, 1 ]; barrier = new Barrier(3); spawn(&sorter, thisTid, numbers[0 .. $ / 2], 0); spawn(&sorter, thisTid, numbers[$ / 2 .. $], 1); writefln("Waiting for barrier in main"); barrier.wait(); writefln("All done"); writeln(numbers); }
Jan 31 2013
Thank you very much for the code. It works fine and is extremely useful.
Jan 31 2013
On Wednesday, 30 January 2013 at 22:58:36 UTC, Sparsh Mittal wrote:Background: I am implementing an iterative algorithm in parallel manner. The algorithm iteratively updates a matrix (2D grid) of data. So, I will "divide" the grid to different threads, which will work on it for single iteration. After each iteration, all threads should wait since next iteration depends on previous iteration. My issue: To achieve synchronization, I am looking for an equivalent of sync in Cilk or cudaEventSynchronize in CUDA. I saw "synchronized", but was not sure, if that is the answer. Please help me. I will put that command at end of "for" loop and it will be executed once per iteration.You could look at this Rosetta Code snippet, which does something similiar for parallelism. http://rosettacode.org/wiki/Checkpoint_synchronization#D
Jan 31 2013