Olivier Teytaud: <aa5e3c330911250005v1d434a5bj8a09067a620ef...@mail.gmail.com>: >> In your (or Sylvain's?) recent paper, you wrote less than one second >> interval was useless. I've observed similar. I'm now evaluating the >> performance with 0.2, 0.4, 1 and 4 second intervals for 5 second per >> move setting on 19x19 board on 32 nodes of HA8000 cluster. >> > >Yes, one second is fine for 5 seconds per move. >Maybe you can check if you have a linear speed-up if you artificially >simulate a >zero communication time ? >My guess is that the communication time should not be a trouble, but if you >don't use MPI, maybe there's something in your implementation of >communications ?
Hmm, I think my communication code is not a trouble. >By the way, a cluster parallelization in MPI can be developped very quickly >and >MPI is efficient - mpi_all_reduce has a computational cost logarithmic in >the number of nodes. Even if the sum-up is done in a logarithmic time (with binary tree style), the collecting time of all infomation from all nodes is proportional to the number of nodes if the master node has few communication ports, isn't it? MPI is a best choice for dedicated HPC clusters, I agree. It forces, however, several constraints such as each node cannot be unplugged or plugged during operation. MPI cannot be installed some computers with not-so-common operating systems or small computers with not enough memory, such as game cosoles. I just want freer parallel and distributed computing environment for MCTS than MPI. My code is now running on a mini pc cluster at my home. I don't want to install MPI to my computers :). By the way, have you experimented not averaging but just adding sceme? When I tested that my code had some bugs and no success. >Good luck, Thanks, Hideki -- g...@nue.ci.i.u-tokyo.ac.jp (Kato) _______________________________________________ computer-go mailing list computer-go@computer-go.org http://www.computer-go.org/mailman/listinfo/computer-go/
