[mpich-discuss] MPI_Comm_spawn crosses node boundaries

Mccall, Kurt E. (MSFC-EV41) kurt.e.mccall at nasa.gov
Mon Feb 7 12:41:26 CST 2022


Ken,

To review, I configured as follows:

$ configure   CFLAGS=-DUSE_PMI2_API   LIBS=-lpmi2   --with-pm=none   --with-pmi=slurm   --with-slurm=/opt/slurm     < ...>

and ran srun with the argument --mpi=pmi2.

The job is stil segfaulting in MPI_Comm_spawn in one process and returning an error from MPI_Barrier in the other.   Error messages below:


The MPI_Comm_spawn error:


backtrace for error: backtrace after receiving signal SIGSEGV:
    /home/kmccall/Needles2/./NeedlesMpiMM() [0x45ab36]
    /lib64/libpthread.so.0(+0x12c20) [0x7f4833387c20]
    /lib64/libc.so.6(+0x15d6b7) [0x7f483310d6b7]
    /lib64/libc.so.6(__strdup+0x12) [0x7f4833039802]
    /lib64/libpmi2.so.0(+0x171c) [0x7f483294371c]
    /lib64/libpmi2.so.0(+0x185e) [0x7f483294385e]
    /lib64/libpmi2.so.0(PMI2_Job_Spawn+0x1a7) [0x7f48329453d8]
    /home/kmccall/mpich-slurm-install-4.0_2/lib/libmpi.so.12(+0x23a7db) [0x7f4834e0a7db]
    /home/kmccall/mpich-slurm-install-4.0_2/lib/libmpi.so.12(+0x1fc805) [0x7f4834dcc805]
    /home/kmccall/mpich-slurm-install-4.0_2/lib/libmpi.so.12(MPI_Comm_spawn+0x507) [0x7f4834cea9f7]


The MPI_Barrier error:

MPI_Barrier returned the error MPI runtime error: Unknown error class, error stack:
internal_Barrier(84).......................: MPI_Barrier(MPI_COMM_WORLD) failed
MPIR_Barrier_impl(91)......................:
MPIR_Barrier_allcomm_auto(45)..............:
MPIR_Barrier_intra_dissemination(39).......:
MPIDI_CH3U_Complete_posted_with_error(1090): Process failed




Thanks,
Kurt

-----Original Message-----
From: Raffenetti, Ken <raffenet at anl.gov> 
Sent: Friday, February 4, 2022 4:08 PM
To: Mccall, Kurt E. (MSFC-EV41) <kurt.e.mccall at nasa.gov>; discuss at mpich.org
Subject: [EXTERNAL] Re: [mpich-discuss] MPI_Comm_spawn crosses node boundaries

:(. We need to link -lpmi2 instead of -lpmi. This really needs a patch in our configure script, but adding this to your configure is worth a shot:

  LIBS=-lpmi2

Ken

On 2/4/22, 1:56 PM, "Mccall, Kurt E. (MSFC-EV41)" <kurt.e.mccall at nasa.gov> wrote:

    I added the CFLAGS argument and the configuration completed, but make ended with a link error.

    lib/.libs/libmpi.so: undefined reference to `PMI2_Abort'
    lib/.libs/libmpi.so: undefined reference to `PMI2_Info_GetJobAttr'
    lib/.libs/libmpi.so: undefined reference to `PMI2_Job_Spawn'
    lib/.libs/libmpi.so: undefined reference to `PMI2_Nameserv_publish'
    lib/.libs/libmpi.so: undefined reference to `PMI2_Finalize'
    lib/.libs/libmpi.so: undefined reference to `PMI2_KVS_Put'
    lib/.libs/libmpi.so: undefined reference to `PMI2_Info_GetNodeAttr'
    lib/.libs/libmpi.so: undefined reference to `PMI2_KVS_Get'
    lib/.libs/libmpi.so: undefined reference to `PMI2_KVS_Fence'
    lib/.libs/libmpi.so: undefined reference to `PMI2_Nameserv_unpublish'
    lib/.libs/libmpi.so: undefined reference to `PMI2_Info_PutNodeAttr'
    lib/.libs/libmpi.so: undefined reference to `PMI2_Job_GetId'
    lib/.libs/libmpi.so: undefined reference to `PMI2_Init'
    lib/.libs/libmpi.so: undefined reference to `PMI2_Nameserv_lookup'
    collect2: error: ld returned 1 exit status

    -----Original Message-----
    From: Raffenetti, Ken <raffenet at anl.gov> 
    Sent: Friday, February 4, 2022 1:23 PM
    To: Mccall, Kurt E. (MSFC-EV41) <kurt.e.mccall at nasa.gov>; discuss at mpich.org
    Subject: [EXTERNAL] Re: [mpich-discuss] MPI_Comm_spawn crosses node boundaries

    I think I see a new issue. The Slurm website documentation says that their PMI library doesn't support PMI_Spawn_multiple from the PMI 1 API. We can try to force PMI 2 and see what happens. Try adding this to your configure line.

      CFLAGS=-DUSE_PMI2_API

    Ken

    On 2/4/22, 11:58 AM, "Mccall, Kurt E. (MSFC-EV41)" <kurt.e.mccall at nasa.gov> wrote:

        Did that, and launched the job with "srun --mpi=none" and one of the processes failed when MPI_Comm_spawn was called.   Note the :

        internal_Comm_spawn(101)......: MPI_Comm_spawn(command=NeedlesMpiMM, argv=0x226b030, maxprocs=1, info=0x9c000000, 0, MPI_COMM_SELF, intercomm=0x7ffffda9448c, array_of_errcodes=0x7ffffda94378) failed
        MPIDI_Comm_spawn_multiple(225): PMI_Spawn_multiple returned -1



        The other process failed when MPI_Barrier was called:


        internal_Barrier(84).......................: MPI_Barrier(MPI_COMM_WORLD) failed
        MPIR_Barrier_impl(91)......................:
        MPIR_Barrier_allcomm_auto(45)..............:
        MPIR_Barrier_intra_dissemination(39).......:
        MPIDI_CH3U_Complete_posted_with_error(1090): Process failed
        MPI runtime error: Unknown error class, error stack:
        internal_Barrier(84).......................: MPI_Barrier(MPI_COMM_WORLD) failed
        MPIR_Barrier_impl(91)......................:
        MPIR_Barrier_allcomm_auto(45)..............:
        MPIR_Barrier_intra_dissemination(39).......:
        MPIDI_CH3U_Complete_posted_with_error(1090): Process failed
        MPI runtime error: Unknown error class, error stack:
        internal_Barrier(84).......................: MPI_Barrier(MPI_COMM_WORLD) failed
        MPIR_Barrier_impl(91)......................:
        MPIR_Barrier_allcomm_auto(45)..............:
        MPIR_Barrier_intra_dissemination(39).......:
        MPIDI_CH3U_Complete_posted_with_error(1090): Process failed
        MPI manager 1 threw exception: MPI runtime error: Unknown error class, error stack:
        internal_Barrier(84).......................: MPI_Barrier(MPI_COMM_WORLD) failed
        MPIR_Barrier_impl(91)......................:
        MPIR_Barrier_allcomm_auto(45)..............:
        MPIR_Barrier_intra_dissemination(39).......:
        MPIDI_CH3U_Complete_posted_with_error(1090): Process failed

        -----Original Message-----
        From: Raffenetti, Ken <raffenet at anl.gov> 
        Sent: Friday, February 4, 2022 11:42 AM
        To: Mccall, Kurt E. (MSFC-EV41) <kurt.e.mccall at nasa.gov>; discuss at mpich.org
        Subject: [EXTERNAL] Re: [mpich-discuss] MPI_Comm_spawn crosses node boundaries

        Yes, you should also use --with-pm=none. If using mpicc to build your application, you should not have to add -lpmi. The script will handle it for you.

        If using another method, you might have to add it. These days with shared libraries, linkers are often able to manage "inter-library" dependencies just fine. Static builds are a different story.

        Ken

        On 2/4/22, 11:35 AM, "Mccall, Kurt E. (MSFC-EV41)" <kurt.e.mccall at nasa.gov> wrote:

            Ken,

            >> configure --with-slurm=/opt/slurm --with-pmi=slurm

            That is similar to your first suggestion below.   With the above, do I have to include --with-pm=none?   I guess I also have to link my application with -lpmi, right?

            Thanks,
            Kurt

            -----Original Message-----
            From: Raffenetti, Ken <raffenet at anl.gov> 
            Sent: Friday, February 4, 2022 11:02 AM
            To: Mccall, Kurt E. (MSFC-EV41) <kurt.e.mccall at nasa.gov>; discuss at mpich.org
            Subject: [EXTERNAL] Re: [mpich-discuss] MPI_Comm_spawn crosses node boundaries

            When running with srun you need to use the Slurm PMI library, not the embedded Simple PMI2 library. Simple PMI2 is API compatible, but uses a different wire protocol that the Slurm implementation. Try this instead:

              configure --with-slurm=/opt/slurm --with-pmi=slurm

            This will link the Slurm PMI library to MPICH. I do acknowledge how confusing this must be to users :). Probably a good FAQ topic for our Github discussions page.

            Ken

            On 2/3/22, 7:00 PM, "Mccall, Kurt E. (MSFC-EV41)" <kurt.e.mccall at nasa.gov> wrote:

                Ken,

                I'm trying to build MPICH 4.0 in several ways, one of which will be what you suggested below.   For this particular attempt suggested by the Slurm MPI guide, I built it with

                configure --with-slurm=/opt/slurm --with-pmi=pmi2/simple <etc>

                and invoked it with

                srun --mpi=pmi2 <etc>

                The job is crashing with this message.   Any idea what is wrong?

                slurmstepd: error: mpi/pmi2: no value for key  in req
                slurmstepd: error: mpi/pmi2: no value for key  in req
                slurmstepd: error: mpi/pmi2: no value for key <99>è­þ^? in req
                slurmstepd: error: mpi/pmi2: no value for key  in req
                slurmstepd: error: mpi/pmi2: no value for key  in req
                slurmstepd: error: mpi/pmi2: no value for key ´2¾ÿ^? in req
                slurmstepd: error: mpi/pmi2: no value for key ; in req
                slurmstepd: error: mpi/pmi2: no value for key  in req
                slurmstepd: error: *** STEP 52227.0 ON n001 CANCELLED AT 2022-02-03T18:48:02 ***

                -----Original Message-----
                From: Raffenetti, Ken <raffenet at anl.gov> 
                Sent: Friday, January 28, 2022 3:15 PM
                To: Mccall, Kurt E. (MSFC-EV41) <kurt.e.mccall at nasa.gov>; discuss at mpich.org
                Subject: [EXTERNAL] Re: [mpich-discuss] MPI_Comm_spawn crosses node boundaries

                On 1/28/22, 2:22 PM, "Mccall, Kurt E. (MSFC-EV41)" <kurt.e.mccall at nasa.gov> wrote:

                    Ken,

                    I confirmed that MPI_Comm_spawn fails completely if I build MPICH without the PMI2 option.

                Dang, I thought that would work :(.

                    Looking at the Slurm documentation https://gcc02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fslurm.schedmd.com%2Fmpi_guide.html%23intel_mpiexec_hydra&data=04%7C01%7Ckurt.e.mccall%40nasa.gov%7C9249f74763f1428b909908d9e82adeef%7C7005d45845be48ae8140d43da96dd17b%7C0%7C0%7C637796093091225985%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=dcpAlSu4FLsL2o39rDH0t1jyzq4AYSOQlZXMReZmmJU%3D&reserved=0
                    it states  "All MPI_comm_spawn work fine now going through hydra's PMI 1.1 interface."   The full quote is below for reference.

                    1) how do I build MPICH to support hydra's PMI 1.1 interface?

                That is the default, so no extra configuration should be needed. One thing I notice in your log output is that the Slurm envvars seems to have changed name from what we have in our source. E.g. SLURM_JOB_NODELIST vs. SLURM_NODELIST. Do your initial processes launch on the right nodes?

                    2) Can you offer any guesses on how to build Slurm to do the same?  (I realize this isn't a Slurm forum  😊)

                Hopefully you don't need to rebuild Slurm to do it. What you could try is configuring the Slurm PMI library when building MPICH. Add "--with-pm=none --with-pmi=slurm --with-slurm=<path/to/install>". Then use srun instead of mpiexec and see how it goes.

                Ken







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