[Mvapich-discuss] Configure issue: enables MPI 4 suite when detecting MPI_Session_Init

[Subramoni, Hari]

Hi, Antoine.

Many thanks for reporting this issue to us. Your observation is correct. We will look into this and fix it. It should be available with the next release of OMB.

Best,
Hari.

-----Original Message-----
From: Mvapich-discuss <mvapich-discuss-bounces at lists.osu.edu> On Behalf Of ANTOINE MORVAN via Mvapich-discuss
Sent: Monday, March 18, 2024 5:54 AM
To: mvapich-discuss at lists.osu.edu
Subject: [Mvapich-discuss] Configure issue: enables MPI 4 suite when detecting MPI_Session_Init

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Hello, 

I was playing with the OSU benchmark 7.3 with Intel OneAPI & Intel MPI 2024 version.

By default, the build is failing with some undefined symbols:

make[4]: *** Waiting for unfinished jobs....
osu_bcast_persistent.o: In function `main':
osu_bcast_persistent.c:(.text+0x3f3): undefined reference to `MPI_Bcast_init'
osu_reduce_persistent.o: In function `main':
osu_reduce_persistent.c:(.text+0x41d): undefined reference to `MPI_Reduce_init'
osu_allreduce_persistent.o: In function `main':
osu_allreduce_persistent.c:(.text+0x41b): undefined reference to `MPI_Allreduce_init'
osu_alltoall_persistent.o: In function `main':
osu_alltoall_persistent.c:(.text+0x4c5): undefined reference to `MPI_Alltoall_init'
osu_gather_persistent.o: In function `main':
osu_gather_persistent.c:(.text+0x43b): undefined reference to `MPI_Gather_init'
osu_scatter_persistent.o: In function `main':
osu_scatter_persistent.c:(.text+0x4a6): undefined reference to `MPI_Scatter_init'
osu_scatter_persistent.c:(.text+0x4f3): undefined reference to `MPI_Scatter_init'

After further investigation, it appears that the configure script of the OSU benchmarks is enabling the MPI 4 benchmarks when detecting MPI_Session_Init available in the MPI implementation. 
The Intel MPI 2021 update 11 bundled with OneAPI 2024 does provide an implementation for MPI sessions (https://urldefense.com/v3/__https://www.intel.com/content/www/us/en/developer/articles/release-notes/mpi-library-release-notes.html__;!!KGKeukY!2fwDrANnfX4-Ec39ASWOQKXsoFaVuD_wWBcF5egWOKZ8PB4qviFiBZfuBdyQKRpeo50eSNprVVLqxdIhKsnN3RBFcZ-EVee7tmAN$ ) but does not exposes all of the MPI 4 API. So, relying on just the sessions would not be enough to ensure the MPI implementation is MPI 4 ready.

On top of this, the configure help clearly states that MPI 4 benchmarks are disabled bby default : 

$OSU_SRC/configure --help
[...]
  --enable-mpi4           Enables MPI4 support and features for benchmarks
                          (default is false)

So either the help is not up to date (it does enable the MPI 4 depending on some configure logics); or the configure script is faulty.

Best regards,
Antoine Morvan (He/Him)
HPC Application Expert - CEPP (Center for Excellence in Performance Programming) - HPC, AI & Quantum GBL
M: +33 (0) 6 43 12 98 21
12 F RUE DU PATIS TATELIN - 35700 Rennes - France eviden.com



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