Ok Jeff, thaks again. I will let you know any advance or doubt on it.
BR, Víctor. El mar, 17 may 2022 a las 20:51, Jeff Squyres (jsquyres) (< jsquy...@cisco.com>) escribió: > Just to clarify: Open MPI's "out of band" messaging *used* to be called > "OOB". Then PMIx split off into its own project, and Open MPI effectively > offloaded our out-of-band messaging to PMIx. > > If you want to inspect PMIx messages, you'll need to look at the headers > in its source code repo: https://github.com/openpmix/openpmix/. It's a > different project than Open MPI, but you can certainly ask questions on > their mailing lists, too. > > -- > Jeff Squyres > jsquy...@cisco.com > > ________________________________________ > From: victor sv <victo...@gmail.com> > Sent: Tuesday, May 17, 2022 4:00 AM > To: Jeff Squyres (jsquyres) > Cc: users@lists.open-mpi.org > Subject: Network traffic packets documentation > > Hi Jeff, > > Thanks for your help. It seems a good point to start :) > > And what about PMIX messages (I think it's called OOB) during the process > spawn? Where can I look the data structure? > > I will probably ask similar questions in the near future. I'm going to > start a proof of concept project (only for fun) to monitor OMPI apps from > different point of views using eBPF (not only network). > > Hopefully you and other active members in the list can help me during the > process. > > Thanks again. > BR, > Víctor. > > > > > > El lunes, 16 de mayo de 2022, Jeff Squyres (jsquyres) <jsquy...@cisco.com > <mailto:jsquy...@cisco.com>> escribió: > Open MPI is generally structured in layers, but adjacent layers don't > necessarily have any knowledge of each other. > > For example, the PML (point-to-point messaging layer) is the first layer > behind MPI point-to-point functions such as MPI_SEND and MPI_RECV. > Different PMLs do not have the same packet layouts, and may, themselves, be > layered. For example, the OB1 PML is mostly a high-level protocol engine > that uses BTLs for low-level sending to and receiving from peers. The > BTLs, therefore, are responsible for their outermost packet formats, and > encapsulate the OB1 payload (which, itself, has a header and a payload). > > If you want to look at the TCP BTL (over the OB1 PML), you can look at the > various structs in opal/mca/btl/tcp. Additionally, you'll need to look at > the OB1 PML structs in ompi/mca/pml/ob1. It's conceivable that you could > make a Wireshark plugin for this use case, for example. The TCP BTL and > OB1 PML structs are subject to change at any time -- it's not like they're > published standards -- but they have been pretty stable for years. > > For other use cases -- e.g., OS-bypass networks -- you'll need to sniff > the packets from the network itself (because, by definition, the OS won't > have visibility of the packets). Regardless, all of those structs are > defined in their BTL / MTL / PML / etc. components. We don't have formal > documentation of any of them, sorry! > > -- > Jeff Squyres > jsquy...@cisco.com<mailto:jsquy...@cisco.com> > > ________________________________________ > From: victor sv <victo...@gmail.com<mailto:victo...@gmail.com>> > Sent: Monday, May 16, 2022 1:17 PM > To: Jeff Squyres (jsquyres) > Cc: users@lists.open-mpi.org<mailto:users@lists.open-mpi.org> > Subject: Re: [OMPI users] Network traffic packets documentation > > Hi Jeff, > > Ok, maybe "packet headers" are not the right words. What I would like to > know is how MPI application data is structured inside each packet in order > to dissect and caracterize the messages. > > As a first step I would like to start with TCP over Ethernet (MCA BTL TCP, > I think). How can I figure out how the application data structure looks > like inside network packets? > > In the future I would like to extend it to other network and transport > combinations. > > What do you think? Has it sense? > > Thanks in advance. > Víctor > > El lun, 16 may 2022 a las 15:45, Jeff Squyres (jsquyres) (< > jsquy...@cisco.com<mailto:jsquy...@cisco.com><mailto:jsquy...@cisco.com > <mailto:jsquy...@cisco.com>>>) escribió: > Open MPI doesn't proscribe a specific network protocol for anything. > Indeed, each network transport uses their own protocols, headers, etc. > It's basically a "each Open MPI plugin needs to be able to talk to itself", > and therefore no commonality is needed (or desired). > > Which network and Open MPI transport are you looking to sniff? > > -- > Jeff Squyres > jsquy...@cisco.com<mailto:jsquy...@cisco.com><mailto:jsquy...@cisco.com > <mailto:jsquy...@cisco.com>> > > ________________________________________ > From: users <users-boun...@lists.open-mpi.org<mailto: > users-boun...@lists.open-mpi.org><mailto:users-boun...@lists.open-mpi.org > <mailto:users-boun...@lists.open-mpi.org>>> on behalf of victor sv via > users <users@lists.open-mpi.org<mailto:users@lists.open-mpi.org><mailto: > users@lists.open-mpi.org<mailto:users@lists.open-mpi.org>>> > Sent: Sunday, May 15, 2022 3:55 PM > To: users@lists.open-mpi.org<mailto:users@lists.open-mpi.org><mailto: > users@lists.open-mpi.org<mailto:users@lists.open-mpi.org>> > Cc: victor sv > Subject: [OMPI users] Network traffic packets documentation > > Hello, > > I would like to sniff the OMPI network traffic from outside the MPI > application. > > I was traversing the OpenMPI code and documentation, but I have not found > any central point explaining MPI communications from the network point of > view. > > Please, is there any official documentation, or paper, or presentation or > picture about MPI packet headers? > > Sorry if this a basic question or if it was already answered. > > Thanks in advance for your help! > BR, > Víctor. >
