Stack Overflow
Stack Overflow

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.
177 questions
1
vote
0 answers

Relationship among different RDMA libraries

I'm new to RDMA technology, and I'm confused by several rdma libraries. I cannot figure out the relationship among them. The libraries and kernel headers I'm confused with are as follows: 1.rdma-core/libibverbs 2.rdma-core/librdmacm…
MitsuiYang
  • 21
  • 2
1
vote
0 answers

Multiclient server using fork how support rdma rsocket

Now we want to support rdma in our old server and client procces. Before we use server listen tcp socket and accept client connection. Then fork a new child process to handle the client process. It looks like there is limitation supporting fork in…
Jason Liu
  • 21
  • 5
1
vote
1 answer

Client IP address at server using RDMA?

I have an RDMA program which works well. Now I have a requirement that I want to get the client IP address after the RDMA connection is established. Socket API recv automatically provided source address information. How about RDMA? Seems it's base…
Gemini
  • 107
  • 1
  • 9
1
vote
1 answer

RDMA cluster benchmarking

Requirement : I have a cluster of 4 machines and I want to get the collective latency and bandwidth for RDMA Write & RDMA Read operation in full mesh. I used ib_write_lat/ib_read_lat for latency and ib_write_bw/ib_read_bw for bandwidth. But those…
manu ks
  • 63
  • 4
1
vote
0 answers

Can RDMA be used to write to memory-mapped registers?

How are memory accesses to memory-mapped registers intercepted and routed to the correct device (rather than letting them go through to RAM)? Is it possible to use RDMA to write to a memory-mapped register? I suppose the answer to this question is…
Jack Humphries
  • 13,056
  • 14
  • 84
  • 125
1
vote
0 answers

/usr/include/rdma/rdma_cma.h:91:2: error: unknown type name ‘__be16’ __be16 pkey;

when I was install SOft-iWARP on ubuntu16.04 to support the RDMA without the expensive hardware, I met with this. I have both linux-headers-4.8.0-39-generic and linux-headers-4.4.0-64-generic on my computer. Is it the problem of linux-core ? how can…
wenwen zhang
  • 11
  • 1
1
vote
1 answer

libibverbs: Warning: no userspace device-specific driver found for /sys/class/infiniband_verbs/uverbs0

Am getting the below messages when I try to check for install devices with the command ibv_devices. libibverbs: Warning: no userspace device-specific driver found for /sys/class/infiniband_verbs/uverbs1 libibverbs: Warning: no userspace …
Sowparnika
  • 11
  • 1
  • 4
1
vote
0 answers

How to run an Intel MPI RDMA application on Azure within two CentOS A8 VM instances

I can't seem to figure out how to run an Intel MPI RDMA application on Azure within two CentOS A8 VM instances. I am trying to test the RDMA setup on my two Azure A8 virtual machines (VM1, VM2) on the same private network 10.1.1.0/24. Note that, as…
Farhana Sarker
  • 11
  • 1
1
vote
1 answer

RDMA memory buffer

I knew that RDMA requires both sender and receiver register their memory before data transfer. I am wondering if the registered memory on both sender and receiver should be same or not. If same, I think RDMA wastes lots of memory since both side…
Technorc Luke
  • 23
  • 3
1
vote
2 answers

rdma_create_qp() error: invalid argument

I'm new to rdma programming and am currently setting up a simple client/server using ib verbs and rdma cma, but have hit a wall. My server runs and waits for the connection, but my client never connects because it fails at rdma_create_qp(). I'm not…
Pixel Razor
  • 11
  • 4
1
vote
1 answer

crash scenario in Remote Direct Memory Access (RDMA)

My question is quite simple: If a machine's CPU/OS fails, is its memory still usable via Remote Direct Memory Access (RDMA) from remote machine?
HuangJie
  • 1,488
  • 1
  • 16
  • 33
1
vote
0 answers

kernel program RDMA (krping)

I'm using a kernel module to do RDMA transfer in kernel space on Infiniband (krping.c, link: git.openfabrics.org Git - ~sgrimberg/krping.git/summary). The cards I have are Mellanox ConnectX-4 (driver: mlx5), Linux kernel version: 3.13, Ubuntu 12.04,…
S. Salman
  • 590
  • 1
  • 6
  • 22
1
vote
1 answer

RDMA API for Linux kernel

Is there an API for RDMA (Infiniband) that can be used in kernel Space? Most of the API's that I have found are user Space. kDAPL and kAL can be used in the linux kernel; however, I have not yet found sample code to use these API's. Can somebody…
S. Salman
  • 590
  • 1
  • 6
  • 22
1
vote
2 answers

RDMA transfer without mapping memory

I have supplementary processes which should exchange files over IB network. Then the files will be used by other processes. The workflow is following: Create files in /dev/shm Resize files appropriately Map files in process' VM Register mmaped area…
mcsim
  • 1,647
  • 2
  • 16
  • 35
1
vote
1 answer

How to send messages over RDMA (Infiniband) from within KVM code to another instance of KVM?

I am trying to setup an RDMA channel between two instances of KVM. I want to send a simple string between the two instances using RDMA (Infiniband) Verbs API from inside the hypervisor. I don't want to do anything on the user-space - purely kernel…
gohar94
  • 138
  • 1
  • 3
  • 11
1 2 3
…
11 12