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Questions tagged [rdma]

RDMA refers to "Remote Direct Memory Access," which is a set of networking technologies typically used for high performance, low latency communication.

RDMA refers to "Remote Direct Memory Access," which is a set of networking technologies typically used for high performance, low latency communication.

RDMA networks have three main attributes:

  1. Asynchronous queueing: network operations are submitted by adding requests "work queues" which are asynchronously executed by hardware; when complete, the result is returned to software in a "completion queue."
  2. Kernel bypass: userspace processes can submit operations directly to the network adapter hardware without any system calls.
  3. One-sided operations: one system can read from or write into the memory of a remote system without involving any software on the remote system.
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NVMeOF/RDMA sync file modifications

I just set up the NVMeOF/RDMA environment to play around. I have a target node which NVMe SSD is accessed by some client nodes. However, when I delete a file say test on one client node, the rest nodes cannot see this operation and can still read…
shengjiang
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RDMA: Can I safely remove spinlocks from mlx4_post_send() function for one sided RDMA operations?

I am porting linux-rdma to a platform with minimal OS support, e.g., spinlocks are not supported. My application aims to have application-threads and a worker-thread. The application-threads create and enqueue requests to a shared queue. The…
Demy
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ibv_post_send performance optimization in KMDF windows driver

I want to use RDMA in a KMDF driver where the buffer received in an EvtIoWrite will be written directly to remote memory but this operation is performance critical so I'm wondering if there is a way to avoid copying the buffer to an RDMA memory…
CommanderLake
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Is it possible to implement DPDK with RDMA support?

I have learned DPDK uses UIO to bypass kernel and I wonder whether DPDK can work with RDMA. Any advice would be appreciated.
xassqa
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mellanox official website test program gpu_direct_rdma_access occurred Couldn't register GPU MR

I used the official website library of gpu direct rdma, gpu_direct_rdma_access. When I was testing the program, the code reported an error, and the Debug information was as shown in the figure below enter image description here Finally, the reason…
Ccfeiker
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what to change in ibverbs when switching from UD to RC connections

I'm looking at a ibverbs code from Mellanox. With a send/recv operation via ibverbs. The code is using UD connections. But it didnt work when I change qp_type = IBV_QPT_UD to IBV_QPT_RC What do I need to change in this case other then the…
WhoAmIWhereAmIWhatIAmDoing
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rsocket - RDMA API - unable to use SOCK_DGRAM option

i instantiated rsocket object, it fails with error of 'no such file or directory' . rsocket(AF_INET, SOCK_DGRAM, IPPROTO_UDP) how to use function rsendto/rrecvfrom if i cannot has a udp rsocket object? centos7.7, rdma : 52mlnx1-1.52104 thanks
potato.s
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How to get the server to write to memory region of client device over RDMA

As the title suggest I'm trying to send data over to the client (via RDMA) instead of the client sending to the server. All of the examples I can find on the topic is client to the server. Is there any resources/references i can refer to?
MaoMaoCake
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softROCE RDMA same device on different ports

I was wondering if there is a way to create rdma rxe devices with the same device name, but different ports. Essentially, the same RDMA device but with different ports, over different eth interfaces. When I do something like $ sudo rdma link add…
Haris
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RoCE connection problem with MLNX_OFED (RDMA over Converged Ethernet)

I am trying to get RoCe (RDMA over converged ethernet) to work on two workstations. I have installed MLNX_OFED on both computers which are equiped with Mellanox ConnectX-5 EN 100GbE adapters and connected directly to each other via corresponding…
Fiskrens
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Using tensorflow with VERBS support without infiniband device

I am interested in the RDMA support in tensorflow 1.15 for workers and parameter servers to communicate directly without going through CPU. I do not have infiniband VERBS devices but can build tensorflow from source with VERBS support bazel build…
John Jiang
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How to test RDMA code without actual hardware?

I have C++ code which makes use of infiniband verbs for RDMA communication. I need to unit test this code, and thus, the function calls related to RDMA such as ibv_get_device_list() need to succeed without any actual hardware. From my understanding,…
xyz123
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NO CPU interactions in initiating DMA and RDMA operations

I'm trying to build/use a PCIe device using DMA/RDMA, and there're some questions: (1) is it possible to initiate a DMA operation from the device side without interactions with the CPU driver I know in most cases, the CPU driver programs the DMA…
장하민
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MSN (message sequence number) in response for a retransmitted RDMA Read

While running ib_read_bw test for 64K message sizes from Mellanox CX-4 (request initiator) to another RNIC, re-transmissions are happening from Mellanox for the 5th RDMA-READ on-wards for 50KB of data (first 12KBs has been ACKed successfully), after…
Anji M
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rdma-core rsocket server receiver connect fork a new sub process, send return 13 permission denied

Now I am testing rdma-core with fork. In server I use rselect and raccept to receive rsocket connection from client. Server can rrecv the msg from client successfully. But server cannot rsend to client. It return -1 and errno 13 permission…
Jason Liu
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