Hi Michael, I think it will be difficult for us to offer further suggestions without looking at the code ourselves, would you be comfortable sending it?
Lydia On 08/18/2014 05:27 AM, Michael Dietrich wrote: > Hello, > > today I compiled my program with the --fast flag. > Though it made both the serial execution much faster than before, the > parallel one became even slower compared with the serial. I'm still > trying to find any possible mistakes within my code but I can't find > any. Any suggestions? > > bye > > > > Zitat von Tom MacDonald <[email protected]>: > >> Hi Michael, >> >> Without --fast the compiler generates runtime checks, which slows >> down execution time. >> >> Please compile with the --fast flag and see how much execution >> time improvement there is. >> >> Thanks >> >> Tom MacDonald >> >> On Fri, 15 Aug 2014, Tom MacDonald wrote: >> >>> Hi Michael, >>> >>> Thank you for your interest in Chapel! It's good to hear you are >>> studying high performance programming languages. >>> >>> Are you compiling your Chapel program with the --fast option? >>> >>> We need to know that before looking deeper. >>> >>> Thanks >>> >>> Tom MacDonald >>> >>> On Fri, 15 Aug 2014, Michael Dietrich wrote: >>> >>>> Hello, >>>> >>>> I'm working with Chapel due to my bachelor thesis about high >>>> performance programming languages. My current task is to implement a >>>> particle simulation program of which I already have the code in C. It >>>> includes two possible algorithms for calculating the force acting onto >>>> the particles: A simple but ineffective one and the >>>> Barnes-Hut-Algorithm [1] which is much faster but a bit more >>>> complicated. The other calculations aren't that complex so for me only >>>> the calculation of force is important. >>>> >>>> I implemented the simple algorithm at first. For comparing the serial >>>> and parallel execution time I surrounded everything with a >>>> serial-statement, evaluating a bool variable I have to set in the >>>> command line. I didn't implement the multi locale improvement yet so >>>> it runs only on a dual core PC, using forall-loops. Finally the >>>> parallel one only needed half of the time of the serial, yay. >>>> >>>> I continued with Barnes-Hut. This one was a bit more work because the >>>> maintenance of the tree-structure leaves a lot of opportunities for >>>> mistakes. After a bit more time it was working as well. >>>> My issue is about the parallel execution time of this algorithm. Like >>>> in the other one I replaced the crucial for-loop with a forall-loop >>>> (the serial-statement surrounds the whole program). The problem is, >>>> that the parallel execution time is similar to the serial one, >>>> sometimes even longer. >>>> Of course I don't want you to read through all my code, but could you >>>> tell me some possible reasons, why this effect may occur? >>>> >>>> thank you very much >>>> bye >>>> Michael >>>> >>>> >>>> [1] http://beltoforion.de/barnes_hut/barnes_hut_en.html >>>> >>>> >>>> ------------------------------------------------------------------------------ >>>> _______________________________________________ >>>> Chapel-users mailing list >>>> [email protected] >>>> https://lists.sourceforge.net/lists/listinfo/chapel-users >>>> >>> ------------------------------------------------------------------------------ >>> _______________________________________________ >>> Chapel-users mailing list >>> [email protected] >>> https://lists.sourceforge.net/lists/listinfo/chapel-users >>> > > > > ------------------------------------------------------------------------------ > _______________________________________________ > Chapel-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/chapel-users ------------------------------------------------------------------------------ _______________________________________________ Chapel-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/chapel-users
