couldn't allocate MR while test GDR with cuda.

[derekwin]

system info

ubuntu 2204
kernel : 6.5.0-28-generic

nvidia driver and cuda version:

Driver Version: 555.42.02
CUDA Version: 12.5

I install RDMA ofed driver before installing cuda driver and cuda toolkits.

peermem module status:

nvidia_peermem         16384  0
nvidia_uvm           4943872  0
nvidia_drm            122880  0
nvidia_modeset       1368064  1 nvidia_drm
nvidia              54566912  3 nvidia_uvm,nvidia_peermem,nvidia_modeset
video                  73728  1 nvidia_modeset
ib_core               557056  9 rdma_cm,ib_ipoib,nvidia_peermem,iw_cm,ib_umad,rdma_ucm,ib_uverbs,mlx5_ib,ib_cm
drm_kms_helper        274432  4 ast,nvidia_drm
drm                   765952  6 drm_kms_helper,ast,drm_shmem_helper,nvidia,nvidia_drm

error occured:
./ib_send_bw --use_cuda=0

Perftest doesn't supports CUDA tests with inline messages: inline size set to 0

************************************
* Waiting for client to connect... *
************************************
initializing CUDA
Listing all CUDA devices in system:
CUDA device 0: PCIe address is 1B:00
CUDA device 1: PCIe address is 3E:00
CUDA device 2: PCIe address is 89:00
CUDA device 3: PCIe address is B2:00

Picking device No. 0
[pid = 3164333, dev = 0] device name = [NVIDIA GeForce RTX 4090]
creating CUDA Ctx
making it the current CUDA Ctx
CUDA device integrated: 0
cuMemAlloc() of a 131072 bytes GPU buffer
allocated GPU buffer address at 00007c43eac00000 pointer=0x7c43eac00000
Couldn't allocate MR
failed to create mr
Failed to create MR
 Couldn't create IB resources
destroying current CUDA Ctx

./ib_send_bw --use_cuda=0 192.168.2.244

Perftest doesn't supports CUDA tests with inline messages: inline size set to 0
initializing CUDA
Listing all CUDA devices in system:
CUDA device 0: PCIe address is 1B:00
CUDA device 1: PCIe address is 3E:00
CUDA device 2: PCIe address is 89:00
CUDA device 3: PCIe address is B2:00

Picking device No. 0
[pid = 3164350, dev = 0] device name = [NVIDIA GeForce RTX 4090]
creating CUDA Ctx
making it the current CUDA Ctx
CUDA device integrated: 0
cuMemAlloc() of a 131072 bytes GPU buffer
allocated GPU buffer address at 00007847fac00000 pointer=0x7847fac00000
Couldn't allocate MR
failed to create mr
Failed to create MR
 Couldn't create IB resources
destroying current CUDA Ctx

[derekwin]

sry that i didn't notice this suggestion.
8. If GPUDirect is not working, (e.g. you see "Couldn't allocate MR" error message), consider disabling Scatter to CQE feature. Set the environmental variable MLX5_SCATTER_TO_CQE=0. E.g.:
MLX5_SCATTER_TO_CQE=0 ./ib_write_bw -d ib_dev --use_cuda= -a

[derekwin]

after setting MLX5_SCATTER_TO_CQE=0, the problem still exist.

[Jye-525]

@derekwin Did you solve this problem? I encountered the same error now.

[derekwin]

@derekwin Did you solve this problem? I encountered the same error now.

i still have this error. : (

[Jye-525]

@derekwin I just solved it on my side. I test this across 2 nodes, but I only load the nvidia-peermem on one of the nodes. It is solved by loading nvidia-peermem on all the nodes. Here is the command:
sudo modprobe nvidia-peermem

You can use lsmod|grep nvidia_peermem to check if it is loaded. Hope it works for you too.

[YuMJie]

If only one of the two machines is capable of supporting GDR, and the other is a consumer-grade graphics card, how should the bandwidth of GDR be tested?