{"action":"created","issue":{"url":"https://api.github.com/repos/mpip/pfft/issues/6","labels_url":"https://api.github.com/repos/mpip/pfft/issues/6/labels{/name}","comments_url":"https://api.github.com/repos/mpip/pfft/issues/6/comments","events_url":"https://api.github.com/repos/mpip/pfft/issues/6/events","html_url":"https://github.com/mpip/pfft/issues/6","id":71981786,"number":6,"title":"New many core systems.","user":{"login":"rainwoodman","id":138060,"avatar_url":"https://avatars.githubusercontent.com/u/138060?v=3","gravatar_id":"","url":"https://api.github.com/users/rainwoodman","html_url":"https://github.com/rainwoodman","followers_url":"https://api.github.com/users/rainwoodman/followers","following_url":"https://api.github.com/users/rainwoodman/following{/other_user}","gists_url":"https://api.github.com/users/rainwoodman/gists{/gist_id}","starred_url":"https://api.github.com/users/rainwoodman/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/rainwoodman/subscriptions","organizations_url":"https://api.github.com/users/rainwoodman/orgs","repos_url":"https://api.github.com/users/rainwoodman/repos","events_url":"https://api.github.com/users/rainwoodman/events{/privacy}","received_events_url":"https://api.github.com/users/rainwoodman/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":6,"created_at":"2015-04-29T20:29:32Z","updated_at":"2015-09-05T03:21:04Z","closed_at":null,"body":"The next generation of Intel will have something like 70+ cores (Knight Landing); mass deployment to major computing facilities will be next year. \r\n\r\nIt may be a good case if PFFT can both scale out and scale in."},"comment":{"url":"https://api.github.com/repos/mpip/pfft/issues/comments/137897245","html_url":"https://github.com/mpip/pfft/issues/6#issuecomment-137897245","issue_url":"https://api.github.com/repos/mpip/pfft/issues/6","id":137897245,"user":{"login":"mpip","id":4056386,"avatar_url":"https://avatars.githubusercontent.com/u/4056386?v=3","gravatar_id":"","url":"https://api.github.com/users/mpip","html_url":"https://github.com/mpip","followers_url":"https://api.github.com/users/mpip/followers","following_url":"https://api.github.com/users/mpip/following{/other_user}","gists_url":"https://api.github.com/users/mpip/gists{/gist_id}","starred_url":"https://api.github.com/users/mpip/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/mpip/subscriptions","organizations_url":"https://api.github.com/users/mpip/orgs","repos_url":"https://api.github.com/users/mpip/repos","events_url":"https://api.github.com/users/mpip/events{/privacy}","received_events_url":"https://api.github.com/users/mpip/received_events","type":"User","site_admin":false},"created_at":"2015-09-05T03:21:04Z","updated_at":"2015-09-05T03:21:04Z","body":"PFFT uses FFTW for the computation of local FFTs, local memory transpositions (that are necessary to ensure the right memory order for MPI Alltoall) and global (parallel) memory transpositions. The master branch of PFFT already supports OpenMP builds via configure option --enable-openmp. This switches on OpenMP support of FFTW in all steps. However, FFTW gives almost no speedup in the local and global transposition steps. In many cases the communication part is very time consuming. In addition, there some special features of PFFT that do not have OpenMP support at the moment. For example,\r\n- pruned PFFT\r\n- ghost cell exchange and reduce\r\n\r\nFor pruned FFT, we have to  reorder an contiguous array into a strided array. I'm not sure if this can be done efficiently with OpenMP.\r\n\r\nFor ghost cell send we have to the same. In addition, the MPI communication will not benefit from more threads."}}