Re: [gmx-users] Minimal PCI Bandwidth for Gromacs and Infiniband?

2018-03-12 Thread Szilárd Páll
Two things I forgot: - Ryzen chipsets are limited in the number of PCIE lanes, so if you plug in a second card (e.g. IB), you'll get x8 on both, which means GPU transfers will be slower too. Now, this may not be a great issue if you run multiple ranks per GPU which will provide some

Re: [gmx-users] Minimal PCI Bandwidth for Gromacs and Infiniband?

2018-03-12 Thread Szilárd Páll
Hi, Note that it matters a lot how far you want to parallelize and what kind of runs would you do? 10 GbE with RoCE may well be enough to scale across a couple of such nodes, especially if you can squeeze PME into a single node and avoid the MPI collectives across the network. You may not even

Re: [gmx-users] Minimal PCI Bandwidth for Gromacs and Infiniband?

2018-03-12 Thread Mark Abraham
Hi, GROMACS doesn't much care about bandwidth, but rather message latency and message injection rate (which in some cases depends on what else is sharing the network). For those, even high quality gigabit ethernet *can* be good enough, so likely any Infiniband product will be just fine.

Re: [gmx-users] Minimal PCI Bandwidth for Gromacs and Infiniband?

2018-03-12 Thread Simon Kit Sang Chu
Hi everyone, Our group is also interested in purchasing cloud GPU cluster. Amazon only supplies GPU cluster connected by 10Gb/s bandwidth. I notice this post but there is no reply by far. It would be nice if someone give any clue. Regards, Simon 2018-03-06 1:31 GMT+08:00 Daniel Bauer