I have pushed the changes to the OMPI master. It took a little bit more than I had hoped due to the changes to the ORTE infrastructure, but hopefully this will meet your needs. It consists of two new tools:
(a) orte-dvm - starts the virtual machine by launching a daemon on every node of the allocation, as constrained by -host and/or -hostfile. Check the options for outputting the URI as you’ll need that info for the other tool. The DVM remains “up” until you issue the orte-submit -terminate command, or hit the orte-dvm process with a sigterm. (b) orte-submit - takes the place of mpirun. Basically just packages your app and arguments and sends it to orte-dvm for execution. Requires the URI of orte-dvm. The tool exits once the job has completed execution, though you can run multiple jobs in parallel by backgrounding orte-submit or issuing commands from separate shells. I’ve added man pages for both tools, though they may not be complete. Also, I don’t have all the mapping/ranking/binding options supported just yet as I first wanted to see if this meets your basic needs before worrying about the detail. Let me know what you think Ralph > On Jan 21, 2015, at 4:07 PM, Mark Santcroos <mark.santcr...@rutgers.edu> > wrote: > > Hi Ralph, > > All makes sense! Thanks a lot! > > Looking forward to your modifications. > Please don't hesitate to through things with rough-edges to me! > > Cheers, > > Mark > >> On 21 Jan 2015, at 23:21 , Ralph Castain <r...@open-mpi.org> wrote: >> >> Let me address your questions up here so you don’t have to scan thru the >> entire note. >> >> PMIx rationale: PMI has been around for a long time, primarily used inside >> the MPI library implementations to perform wireup. It provided a link from >> the MPI library to the local resource manager. However, as we move towards >> exascale, two things became apparent: >> >> 1. the current PMI implementations don’t scale adequately to get there. The >> API created too many communications and assumed everything was a blocking >> operation, thus preventing asynchronous progress >> >> 2. there were increasing requests for application-level interactions to the >> resource manager. People want ways to spawn jobs (and not just from within >> MPI), request pre-location of data, control power, etc. Rather than having >> every RM write its own interface (and thus make everyone’s code >> non-portable), we at Intel decided to extend the existing PMI definitions to >> support those functions. Thus, an application developer can directly access >> PMIx functions to perform all those operations. >> >> PMIx v1.0 is about to be released - it’ll be backward compatible with PMI-1 >> and PMI-2, plus add non-blocking operations and significantly reduce the >> number of communications. PMIx 2.0 is slated for this summer and will >> include the advanced controls capabilities. >> >> ORCM is being developed because we needed a BSD-licensed, fully featured >> resource manager. This will allow us to integrate the RM even more tightly >> to the file system, networking, and other subsystems, thus achieving higher >> launch performance and providing desired features such as QoS management. >> PMIx is a part of that plan, but as you say, they each play their separate >> roles in the overall stack. >> >> >> Persistent ORTE: there is a learning curve on ORTE, I fear. We do have some >> videos on the web site that can help get you started, and I’ve given a >> number of “classes" at Intel now for that purpose. I still have it on my >> “to-do” list that I summarize those classes and post them on the web site. >> >> For now, let me summarize how things work. At startup, mpirun reads the >> allocation (usually from the environment, but it depends on the host RM) and >> launches a daemon on each allocated node. Each daemon reads its local >> hardware environment and “phones home” to let mpirun know it is alive. Once >> all daemons have reported, mpirun maps the processes to the nodes and sends >> that map to all the daemons in a scalable broadcast pattern. >> >> Upon receipt of the launch message, each daemon parses it to identify which >> procs it needs to locally spawn. Once spawned, each proc connects back to >> its local daemon via a Unix domain socket for wireup support. As procs >> complete, the daemon maintains bookkeeping and reports back to mpirun once >> all procs are done. When all procs are reported complete (or one reports as >> abnormally terminated), mpirun sends a “die” message to every daemon so it >> will cleanly terminate. >> >> What I will do is simply tell mpirun to not do that last step, but instead >> to wait to receive a “terminate” cmd before ending the daemons. This will >> allow you to reuse the existing DVM, making each independent job start a >> great deal faster. You’ll need to either manually terminate the DVM, or the >> RM will do so when the allocation expires. >> >> HTH >> Ralph >> >> >>> On Jan 21, 2015, at 12:52 PM, Mark Santcroos <mark.santcr...@rutgers.edu> >>> wrote: >>> >>> Hi Ralph, >>> >>>> On 21 Jan 2015, at 21:20 , Ralph Castain <r...@open-mpi.org> wrote: >>>> >>>> Hi Mark >>>> >>>>> On Jan 21, 2015, at 11:21 AM, Mark Santcroos <mark.santcr...@rutgers.edu> >>>>> wrote: >>>>> >>>>> Hi Ralph, all, >>>>> >>>>> To give some background, I'm part of the RADICAL-Pilot [1] development >>>>> team. >>>>> RADICAL-Pilot is a Pilot System, an implementation of the Pilot (job) >>>>> concept, which is in its most minimal form takes care of the decoupling >>>>> of resource acquisition and workload management. >>>>> So instead of launching your real_science.exe through PBS, you submit a >>>>> Pilot, which will allow you to perform application level scheduling. >>>>> Most obvious use-case if you want to run many (relatively) small tasks, >>>>> then you really don;t want to go through the batch system every time. >>>>> That is besides the fact that these machines are very bad in managing >>>>> many tasks anyway. >>>> >>>> Yeah, we sympathize. >>> >>> Thats always good :-) >>> >>>> Of course, one obvious solution is to get an allocation and execute a >>>> shell script that runs the tasks within that allocation - yes? >>> >>> Not really. Most of our use-cases have dynamic runtime properties, which >>> means that at t=0 the exact workload is not known. >>> >>> In addition, I don't think such a script would allow me to work around the >>> aprun bottleneck, as I'm not aware of a way to start MPI tasks that span >>> multiple nodes from a Cray worker node. >>> >>>>> I looked a bit better at ORCM and it clearly overlaps with what I want to >>>>> achieve. >>>> >>>> Agreed. In ORCM, we allow a user to request a “session” that results in >>>> allocation of resources. Each session is given an “orchestrator” - the >>>> ORCM “shepherd” daemon - responsible for executing the individual tasks >>>> across the assigned allocation, and a collection of “lamb” daemons (one on >>>> each node of the allocation) that forms a distributed VM. The orchestrator >>>> can execute the tasks very quickly since it doesn’t have to go back to the >>>> scheduler, and we allow it to do so according to any provided precedence >>>> requirement. Again, for simplicity, a shell script is the default >>>> mechanism for submitting the individual tasks. >>> >>> Yeah, similar solution to a similar problem. >>> I noticed that Exascale is also part of the motivation? How does this >>> relate to the pmix effort? Different part of the stack I guess. >>> >>>>> One thing I noticed is that parts of it runs as root, why is that? >>>> >>>> ORCM is a full resource manager, which means it has a scheduler >>>> (rudimentary today) and boot-time daemons that must run as root so they >>>> can fork/exec the session-level daemons (that run at the user level). The >>>> orchestrator and its daemons all run at the user-level. >>> >>> Ok. Our solution is user-space only, as one of our features is that we are >>> able to run across different type of systems. Both approaches come with a >>> tradeoff obviously. >>> >>>>>> We used to have a cmd line option in ORTE for what you propose - it >>>>>> wouldn’t be too hard to restore. Is there some reason to do so? >>>>> >>>>> Can you point me to something that I could look for in the repo history, >>>>> then I can see if it serves my purpose. >>>> >>>> It would be back in the svn repo, I fear - would take awhile to hunt it >>>> down. Basically, it just (a) started all the daemons to create a VM, and >>>> (b) told mpirun to stick around as a persistent daemon. All subsequent >>>> calls to mpirun would reference back to the persistent one, thus using it >>>> to launch the jobs against the standing VM instead of starting a new one >>>> every time. >>> >>> *nod* That's what I tried to do this afternoon actually with the >>> "--ompi-server", but that was not meant to be. >>> >>>> For ORCM, we just took that capability and expressed it as the “shepherd” >>>> plus “lamb” daemon architecture described above. >>> >>> ACK. >>> >>>> If you don’t want to replace the base RM, then using ORTE to establish a >>>> persistent VM is probably the way to go. >>> >>> Indeed, thats what it sounds like. Plus that ORTE is generic enough that I >>> can re-use it on other type of systems too. >>> >>>> I can probably make it do that again fairly readily. We have a developer’s >>>> meeting next week, which usually means I have some free time (during >>>> evenings and topics I’m not involved with), so I can take a crack at this >>>> then if that would be timely enough. >>> >>> Happy to accept that offer. At this stage I'm not sure if I would want a >>> CLI or would be more interested to be able to do this programmatically >>> though. >>> Also more than willing to assist in any way I can. >>> >>> I tried to see how it all worked, but because of the modular nature of ompi >>> that was quite daunting. There is some learning curve I guess :-) >>> So it seems that mpirun is persistent, and opens up a listening port, then >>> some orded's get launched that phone home. >>> From there I got lost in the MCA maze. How do the tasks get unto the >>> compute nodes and started? >>> >>> Thanks a lot again, I appreciate your help. >>> >>> Cheers, >>> >>> Mark >>> _______________________________________________ >>> users mailing list >>> us...@open-mpi.org >>> Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users >>> Link to this post: >>> http://www.open-mpi.org/community/lists/users/2015/01/26227.php >> >> _______________________________________________ >> users mailing list >> us...@open-mpi.org >> Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users >> Link to this post: >> http://www.open-mpi.org/community/lists/users/2015/01/26228.php > > _______________________________________________ > users mailing list > us...@open-mpi.org > Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users > Link to this post: > http://www.open-mpi.org/community/lists/users/2015/01/26229.php
