Re: [OMPI users] question about the Open-MPI ABI

Because we’ve screwed up in the past? I think the ompi_message_null was me, and I was in a hurry to prototype for the MPI Forum. And then it stuck. Brian On 2/1/23, 3:16 AM, "users on behalf of Jeff Hammond via users" mailto:users-boun...@lists.open-mpi.org> on behalf of users@lists.open-mpi

Re: [OMPI users] Beginner Troubleshooting OpenMPI Installation - pmi.h Error

Can you include the configure command you used for Open MPI, as well as the output of “make all V=1” (it’s ok if that’s from a tree you’ve already tried to build, the full compile command for the file that is failing to compile is the part of interest. Thanks, Brian On 10/4/22, 9:06 AM, "user

Re: [OMPI users] MPI_THREAD_MULTIPLE question

Yes, this is the case for Open MPI 4.x and earlier, due to various bugs. When Open MPI 5.0 ships, we will resolve this issue. Brian On 9/9/22, 9:58 PM, "users on behalf of mrlong336 via users" mailto:users-boun...@lists.open-mpi.org> on behalf of users@lists.open-mpi.org

Re: [OMPI users] How to set parameters to utilize multiple network interfaces?

John - Open MPI's OFI implementation does not stripe messages across processes. Instead, an Open MPI process will choose the "closest" NIC on the system (based on PCI hops and PCI topology, using hwloc). If there is ore than one "closest" NIC, as is the case on P4, where each Intel socket has

[OMPI users] Open MPI release update

Greetings - As you may know, Open MPI 5.0 is going to include an ambitious improvement in Open MPI's runtime system along with a number of performance improvements, and was targeted to ship this summer. While we are still going to make those improvements to our runtime system, it is taking us

Re: [OMPI users] disabling ucx over omnipath

What you're asking for is an ugly path of interconnected dependencies between products owned by different companies. It also completely blows any object model we can think of out of the water. It's all bad in the general case. The best we've come up with for the Libfabric MTL is to disable it

Re: [OMPI users] Limit to number of asynchronous sends/receives?

Adam - There are a couple of theoretical limits on how many requests you can have outstanding (at some point, you will run the host out of memory). However, those issues should be a problem when posting the MPI_Isend or MPI_Irecv, not during MPI_Waitall. 2.1.0 is pretty old; the first step in

Re: [OMPI users] RDMA over Ethernet in Open MPI - RoCE on AWS?

On Sep 11, 2018, at 10:46 AM, Benjamin Brock mailto:br...@cs.berkeley.edu>> wrote: Thanks for your response. One question: why would RoCE still requiring host processing of every packet? I thought the point was that some nice server Ethernet NICs can handle RDMA requests directly? Or am I mis

Re: [OMPI users] How do I build 3.1.0 (or later) with mellanox's libraries

Yeah, there’s no good answer here from an “automatically do the right thing” point of view. The reachable:netlink component (which is used for the TCP BTL) only works with libnl-3 because libnl-1 is a real pain to deal with if you’re trying to parse route behaviors. It will do the right thing

Re: [OMPI users] RDMA over Ethernet in Open MPI - RoCE on AWS?

It sounds like what you’re asking is “how do I get the best performance from Open MPI in AWS?”. The TCP BTL is your best option for performance in AWS. RoCE is going to be a bunch of work to get setup, and you’ll still end up with host processing of every packet. There are a couple simple ins

[OMPI users] Open MPI v3.1.0 Released

The Open MPI Team, representing a consortium of research, academic, and industry partners, is pleased to announce the release of Open MPI version 3.1.0. v3.1.0 is the start of a new release series for Open MPI. New Features include a monitoring framework to track data movement in MPI operatio

Re: [OMPI users] Q: Binding to cores on AWS?

Jumping in a little late… Today, EC2 instances don’t expose all the required information for memory pinning to work, which is why you see the warning. The action-less error message is obviously a bit annoying (although it makes sense in the general case), but we haven’t had the time to work ou

Re: [OMPI users] How can I measure synchronization time of MPI_Bcast()

Gilles suggested your best next course of action; time the MPI_Bcast and MPI_Barrier calls and see if there’s a non-linear scaling effect as you increase group size. You mention that you’re using m3.large instances; while this isn’t the list for in-depth discussion about EC2 instances (the AWS

[OMPI users] Open MPI v3.0.0 released

The Open MPI Team, representing a consortium of research, academic, and industry partners, is pleased to announce the release of Open MPI version 3.0.0. v3.0.0 is the start of a new release series for Open MPI. Open MPI 3.0.0 enables MPI_THREAD_MULTIPLE by default, so a build option to Open MPI

Re: [OMPI users] --enable-builtin-atomics

Well, if you’re trying to get Open MPI running on a platform for which we don’t have atomics support, built-in atomics solves a problem for you… Brian > On Aug 1, 2017, at 9:42 AM, Nathan Hjelm wrote: > > So far only cons. The gcc and sync builtin atomic provide slower performance > on x86-64

Re: [OMPI users] Network performance over TCP

Adam - The btl_tcp_links flag does not currently work (for various reasons) in the 2.x and 3.x series. It’s on my todo list to fix, but I’m not sure it will get done before the 3.0.0 release. Part of the reason that it hasn’t been a priority is that most applications (outside of benchmarks) d

Re: [OMPI users] [OMPI USERS] Jumbo frames

But in many ways, it’s also not helpful to change the MTU from Open MPI. It sounds like you made a bunch of changes all at once; I’d break them down and build up. MTU is a very system-level configuration. Use a tcp transmission test (iperf, etc.) to make sure TCP connections work between the