Hi Howard, What was the latency with the 4.3.x branch? Rajeev From: Howard Pritchard via discuss <[email protected]> Reply-To: "[email protected]" <[email protected]> Date: Wednesday, July 30, 2025 at 1:43 PM To: "Zhou, Hui" <[email protected]> Cc: Howard Pritchard <[email protected]>, "[email protected]" <[email protected]> Subject: Re: [mpich-discuss] MPICH 5.0.1 performance on HPE SS11 plus more - a slurm problem Hi Hui That didn’t help. I am not surprised though as our cluster is an NVIDIA free zone. What did help is to switch to the mpich 4. 3. x branch and latency results are nominal and the slurm problem went away too. So we will stick with that branch.  ZjQcmQRYFpfptBannerStart This Message Is From an External Sender This message came from outside your organization. ZjQcmQRYFpfptBannerEnd Hi Hui That didn’t help. I am not surprised though as our cluster is an NVIDIA free zone. What did help is to switch to the mpich 4.3.x branch and latency results are nominal and the slurm problem went away too. So we will stick with that branch. Howard On Mon, Jul 28, 2025 at 4:15 PM Zhou, Hui <[email protected]<mailto:[email protected]>> wrote: Hi Howard, I wonder whether it is due to the overhead of querying pointer attributes. Could you try disable GPU support with `MPIR_CVAR_ENABLE_GPU=0` and see if the latency improves? Hui ________________________________ From: Howard Pritchard via discuss <[email protected]<mailto:[email protected]>> Sent: Monday, July 28, 2025 9:41 AM To: [email protected]<mailto:[email protected]> <[email protected]<mailto:[email protected]>> Cc: Howard Pritchard <[email protected]<mailto:[email protected]>> Subject: [mpich-discuss] MPICH 5.0.1 performance on HPE SS11 plus more - a slurm problem Hi Folks, We are seeing a strange performance issue on our HPE SS11 system when testing osu_latency inter-node with MPICH. First the info: system using libfabric 1. 22. 0 slurm - 24. 11. 5 Here's my mpichversion output: MPICH Version:  5. 0. 0a1 ZjQcmQRYFpfptBannerStart This Message Is From an External Sender This message came from outside your organization. ZjQcmQRYFpfptBannerEnd Hi Folks, We are seeing a strange performance issue on our HPE SS11 system when testing osu_latency inter-node with MPICH. First the info: system using libfabric 1.22.0 slurm - 24.11.5 Here's my mpichversion output: MPICH Version: 5.0.0a1 MPICH Release date: unreleased development copy MPICH ABI: 0:0:0 MPICH Device: ch4:ofi MPICH configure: --prefix=/XXXX/mpich_again/install --enable-g=no --enable-error-checking=no --with-device=ch4:ofi --enable-threads=multiple --with-ch4-shmmods=posix,xpmem --enable-thread-cs=per-vci --with-libfabric=/opt/cray/libfabric/1.22.0 --with-xpmem=/opt/cray/xpmem/default --with-pmix=/opt/pmix/gcc4x/5.0.8 --enable-fast=O3 MPICH CC: gcc -O3 MPICH CXX: g++ -O3 MPICH F77: gfortran -O3 MPICH FC: gfortran -O3 MPICH features: threadcomm And here's the OSU latency results: slurmstepd: error: mpi/pmix_v4: pmixp_coll_belong_chk: nid001439 [1]: pmixp_coll.c:280: No process controlled by this slurmstepd is involved in this collective. slurmstepd: error: mpi/pmix_v4: _process_server_request: nid001439 [1]: pmixp_server.c:923: Unable to pmixp_state_coll_get() slurmstepd: error: mpi/pmix_v4: pmixp_coll_ring_check: nid001438 [0]: pmixp_coll_ring.c:614: 0x15005c005dc0: unexpected contrib from nid001439:1, expected is 0 slurmstepd: error: mpi/pmix_v4: _process_server_request: nid001438 [0]: pmixp_server.c:937: 0x15005c005dc0: unexpected contrib from nid001439:1, coll->seq=0, seq=0 slurmstepd: error: mpi/pmix_v4: pmixp_coll_ring_reset_if_to: nid001438 [0]: pmixp_coll_ring.c:738: 0x1500580532f0: collective timeout seq=0 slurmstepd: error: mpi/pmix_v4: pmixp_coll_log: nid001438 [0]: pmixp_coll.c:286: Dumping collective state slurmstepd: error: mpi/pmix_v4: pmixp_coll_ring_log: nid001438 [0]: pmixp_coll_ring.c:756: 0x1500580532f0: COLL_FENCE_RING state seq=0 slurmstepd: error: mpi/pmix_v4: pmixp_coll_ring_log: nid001438 [0]: pmixp_coll_ring.c:758: my peerid: 0:nid001438 slurmstepd: error: mpi/pmix_v4: pmixp_coll_ring_log: nid001438 [0]: pmixp_coll_ring.c:765: neighbor id: next 1:nid001439, prev 1:nid001439 slurmstepd: error: mpi/pmix_v4: pmixp_coll_ring_log: nid001438 [0]: pmixp_coll_ring.c:775: Context ptr=0x150058053368, #0, in-use=0 slurmstepd: error: mpi/pmix_v4: pmixp_coll_ring_log: nid001438 [0]: pmixp_coll_ring.c:775: Context ptr=0x1500580533a0, #1, in-use=0 slurmstepd: error: mpi/pmix_v4: pmixp_coll_ring_log: nid001438 [0]: pmixp_coll_ring.c:775: Context ptr=0x1500580533d8, #2, in-use=1 slurmstepd: error: mpi/pmix_v4: pmixp_coll_ring_log: nid001438 [0]: pmixp_coll_ring.c:786: seq=0 contribs: loc=1/prev=0/fwd=1 slurmstepd: error: mpi/pmix_v4: pmixp_coll_ring_log: nid001438 [0]: pmixp_coll_ring.c:788: neighbor contribs [2]: slurmstepd: error: mpi/pmix_v4: pmixp_coll_ring_log: nid001438 [0]: pmixp_coll_ring.c:821: done contrib: - slurmstepd: error: mpi/pmix_v4: pmixp_coll_ring_log: nid001438 [0]: pmixp_coll_ring.c:823: wait contrib: nid001439 slurmstepd: error: mpi/pmix_v4: pmixp_coll_ring_log: nid001438 [0]: pmixp_coll_ring.c:825: status=PMIXP_COLL_RING_PROGRESS slurmstepd: error: mpi/pmix_v4: pmixp_coll_ring_log: nid001438 [0]: pmixp_coll_ring.c:829: buf (offset/size): 36/16384 slurmstepd: error: mpi/pmix_v4: pmixp_coll_ring_reset_if_to: nid001439 [1]: pmixp_coll_ring.c:738: 0x151d0c053400: collective timeout seq=0 slurmstepd: error: mpi/pmix_v4: pmixp_coll_log: nid001439 [1]: pmixp_coll.c:286: Dumping collective state slurmstepd: error: mpi/pmix_v4: pmixp_coll_ring_log: nid001439 [1]: pmixp_coll_ring.c:756: 0x151d0c053400: COLL_FENCE_RING state seq=0 slurmstepd: error: mpi/pmix_v4: pmixp_coll_ring_log: nid001439 [1]: pmixp_coll_ring.c:758: my peerid: 1:nid001439 slurmstepd: error: mpi/pmix_v4: pmixp_coll_ring_log: nid001439 [1]: pmixp_coll_ring.c:765: neighbor id: next 0:nid001438, prev 0:nid001438 slurmstepd: error: mpi/pmix_v4: pmixp_coll_ring_log: nid001439 [1]: pmixp_coll_ring.c:775: Context ptr=0x151d0c053478, #0, in-use=0 slurmstepd: error: mpi/pmix_v4: pmixp_coll_ring_log: nid001439 [1]: pmixp_coll_ring.c:775: Context ptr=0x151d0c0534b0, #1, in-use=0 slurmstepd: error: mpi/pmix_v4: pmixp_coll_ring_log: nid001439 [1]: pmixp_coll_ring.c:775: Context ptr=0x151d0c0534e8, #2, in-use=1 slurmstepd: error: mpi/pmix_v4: pmixp_coll_ring_log: nid001439 [1]: pmixp_coll_ring.c:786: seq=0 contribs: loc=1/prev=0/fwd=1 slurmstepd: error: mpi/pmix_v4: pmixp_coll_ring_log: nid001439 [1]: pmixp_coll_ring.c:788: neighbor contribs [2]: slurmstepd: error: mpi/pmix_v4: pmixp_coll_ring_log: nid001439 [1]: pmixp_coll_ring.c:821: done contrib: - slurmstepd: error: mpi/pmix_v4: pmixp_coll_ring_log: nid001439 [1]: pmixp_coll_ring.c:823: wait contrib: nid001438 slurmstepd: error: mpi/pmix_v4: pmixp_coll_ring_log: nid001439 [1]: pmixp_coll_ring.c:825: status=PMIXP_COLL_RING_PROGRESS slurmstepd: error: mpi/pmix_v4: pmixp_coll_ring_log: nid001439 [1]: pmixp_coll_ring.c:829: buf (offset/size): 36/16384 # OSU MPI Latency Test v5.8 # Size Latency (us) 0 1.66 1 9.29 2 9.57 4 9.69 8 9.76 16 9.77 32 9.76 64 9.77 128 10.32 256 7.54 512 7.45 1024 7.38 2048 7.37 4096 7.45 8192 9.21 16384 9.70 32768 10.63 65536 13.15 131072 16.96 262144 23.84 524288 36.16 1048576 60.36 2097152 108.43 4194304 228.31 Note the slurm behavior is - I launch the job. Go get coffee, do some duo-lingo, read some emails, then after about 10 minutes the osu latency runs. I did not get the slurm problems using an older mpich 4.3.1 but did get the same performance issue. 9 usecs doesn't seem right for an 8-byte pingpong over libfabric S11. I was expecting more like 1.6 or so. I am confident the slurm issue is unrelated to the latency issue. Thanks for any suggestions on how to address either issue however.