Hi Mikel - As part of learning about parallel programming, using Chapel is absolutely an appropriate way to see the advantages of parallelization. Brad was saying that if you want maximum absolute single-node performance, we don't expect Chapel to beat OpenMP at this time.
Chapel does make it easier to learn about parallel programming because you can learn about single and multi-node programming within a single language that has consistent design. Similarly, you can learn about task-parallelism and data-parallelism within one language. Cheers, -michael On 10/1/15, 6:24 PM, "Mikel Antoñana" <[email protected]> wrote: >Hi, > >Although I have no experience with parallel programming, I have to study >the advantage of >parallelization of one numerical integration method. First, I learned >myself about parallel programming and I considered two alternatives : >OpenMP and MPI. Finally, I have used an OpenMP > because it is simple. > >I have read some documents about Chapel and I like your goals. I hope I >will take time to understand better parallel programming and to learn >programming in Chapel for a future project. > > > > >Thank you for your help. > >Mikel > > > > > >2015-09-30 0:03 GMT+02:00 Brad Chamberlain ><[email protected]>: > > >Hi Mikel -- > >Tom's right that we don't have much free time this week, but a few things >in your message stuck out for me: > >* Increasingly, Chapel's single-node performance is competitive with > C+OpenMP. For a good OpenMP implementation and computation that fits > OpenMP well, I believe it would be challenging for Chapel to outperform > OpenMP. So I think your reasons for moving to Chapel for a scenario > like this would need to be "I want to take advantage of the productivity > and expressiveness features of Chapel" rather than "I want to create > something that outperforms my existing OpenMP code. Put another way, > if OpenMP isn't hampering you, Chapel may not be a win. > >* If you wanted to move to a distributed memory execution, that may be > a reason to move to Chapel since OpenMP can only target shared memory > and accelerators. Whether or not Chapel would give you good performance > in this setting will depend a lot on the characteristics of your > computation... > >* You mention quad precision arithmetic, which is something that Chapel > does not support at present. We discussed adding it early in the > project's history, but at that time, it was difficult to predict > how support for quad precision might vary across machines, so we left > it out for the time being. I suspect adding it in would not be > terribly complicated for a back-end C compiler with good support for > it, but I mostly wanted to emphasize that it is not available today. > >Hope this is helpful, >-Brad > > > >On Tue, 29 Sep 2015, Tom MacDonald wrote: > > >Hi Mikel, > >The Chapel team is racing toward a release this week and >it might take us a few days to respond. We appreciate your >interest and Chapel and ask for a little patience. > >Best wishes, > >Tom MacDonald >Chapel Manager > >On Tue, 29 Sep 2015, Mikel Antoñana wrote: > >Hi, > >I have developed an numerical integration algorithm in language C and I >ask >myself if I should programme it in Chapel to get better performance. >Next, >I give a short description of the algorithm. > > A huge number of integration steps are taken. > Only a small part of the code can be evaluated in parallel (I have used >Open MP model) and the ?fun? evaluation is expensive. >The units of work to run in parallel is small (p.e ns=6), so I carry out >the computation in a multicore desktop. > I need to increase the accuracy of the solution and in the next future, I >will make some computations using quadruple precision arithmetic. > > > Algorithm > > for k=1 to steps > { > ..... > # pragma omp parallel for >num_threads(thread_count) private(isn) > > for (is = 0; is<ns; is++) > { > isn=neq*is; > fun >(neq,u,&z[isn],&fz[isn],params,thestatptr); > } > ..... > } > > >I thank you sincerely your opinion. > > >Regards, >Mikel. > > > > > > > > > > > > > > > > > ------------------------------------------------------------------------------ _______________________________________________ Chapel-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/chapel-users
