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
0
votes
1 answer

NVMoF: how to tell a command capsule from a response capsule

Let's say I have RoCEv2 traffic between 2 nodes A & B. A uses RDMA_SEND to send a command capsule to B. Then A receives a capsule from B (B also uses RDMA_SEND). At this moment, how does A know if this is the response to its command sent in step…
Yao Lin
  • 11
  • 2
0
votes
1 answer

register large buffer for RDMA in Linux kernel module

i'm a newbie experimenting a project using rdma (ib_verbs) in kernel module. I got the example code from krping and tinkering on it. The system run on 64bits Linux Centos with a custom 3.10 Linux kernel that require transparent huge pages…
Chavit
  • 3
  • 4
0
votes
1 answer

What is a Producer index (PI) in the context of ibv_exp_post_send and ibv_exp_post_task?

I am trying to use the Cross-Channel Communication support described in Appendix D to the RDMA Aware Programming User Manual. Unfortunately I am a bit confused as to the meanings of certain function arguments. My Question The ibv_exp_post_send()…
fintelia
  • 1,201
  • 6
  • 17
0
votes
1 answer

Error using verbs Memory Windows (ibv_alloc_mw)

I am trying to use memory windows and I am getting EPERM (errno=1) when calling ibv_alloc_mw (with both types of MWs). I have mellanox ConnectX-3 cards and the following OFED: ofed_info | head -n 1 MLNX_OFED_LINUX-3.2-2.0.0.0 (OFED-3.2-2.0.0): It…
JC1
  • 657
  • 6
  • 21
0
votes
1 answer

RDMA Fast Memory Registration (FMR)

I'm developing a system that uses RDMA extensively (on Mellanox hardware) and would like to be able to register memory regions more efficiently/faster. I have taken a look into Fast Memory Registration and I have a few questions: Is FMR going away?…
JC1
  • 657
  • 6
  • 21
0
votes
1 answer

Issue in SA query Infiniband

What is the parameter context passed to the function ib_sa_path_rec_get from ib_sa?
S. Salman
  • 590
  • 1
  • 6
  • 22
0
votes
1 answer

Issue with ibv_poll_cq() & ib_poll_cq()

Client Side: ib_poll_cq(cq,1,&wc){ if(wc.status == IB_WC_SUCCESS) printk("Successful\n"); else printk("Failure: %d\n", wc.status); } Server Side: do { num_comp = ibv_poll_cq(s_ctx.recv_cq, 1, &wc); } while (num_comp ==…
S. Salman
  • 590
  • 1
  • 6
  • 22
0
votes
1 answer

Krping module for RDMA

I have been trying to make krpring module work which can be found here: http://git.openfabrics.org/?p=~sgrimberg/krping.git;a=summary [ 446.242534] rdma_krping: Unknown symbol ib_alloc_fast_reg_page_list (err -22) [ 446.242542] rdma_krping:…
S. Salman
  • 590
  • 1
  • 6
  • 22
0
votes
1 answer

How to avoid getting stuck in rdma_get_recv_comp() or __ibv_get_cq_event()?

Fellow RDMA hackers, does anyone know if rdma_get_recv_comp(), which calls __ibv_get_cq_event() ever time out? My problem is with the same programs as shown here: RDMA program randomly hangs It works fine, but it's not robust against random client…
Yale Zhang
  • 1,447
  • 12
  • 30
0
votes
1 answer

wireshark decode as ddp

I am using wireshark to look at ddp/rdma packets, which usually works fine. Sometimes wireshark can't recognize that the next protocol after tcp is ddp/rdma (although I know it is), so I tried using "decode as" but there is no option for ddp/rdma in…
user5165960
  • 65
  • 4
0
votes
3 answers

Is it possible to implement RDMA (RoCE) only on client side without worrying about Server RDMA support?

I require to reduce latency of windows application using RDMA,but I have control over only one side of communication,RDMA(Kernel Bypass) implementation irrespective of other side. Is it possible to implement RDMA (RoCE) only on client side without…
Kapil
  • 1
  • 2
0
votes
0 answers

Address already in use in targetcli iser enable

kindly help me to fix this problem I am using "targetcli-2.0rc1" I have created the portal with IP address 192.168.1.11 and port no : 3260 When I am doing "iser_enable" then it throws following error /iscsi/iqn.20...168.1.11:3260> iser_enable…
Dinesh Kb
  • 31
  • 2
0
votes
1 answer

RDMA WRITE: ibv_wc.byte_len does not match what I try to write

I'm an Infiniband/RDMA newbie playing with RDMA on Mellanox Infiniband hardware. I used the source code here. The program runs pretty normal at first glance: The server writes some bytes to the client memory using RDMA_WRITE operation. However, I…
Weijia Song
  • 153
  • 8
0
votes
1 answer

libibverbs Hello World

I'm trying to find a short "Hello World" example that uses Infiniband with libibverbs. This goes into a good direction, but writing "Hello World" to the terminal should be possible in less than 800 lines. I was hoping for something like this.
mrks
  • 8,033
  • 1
  • 33
  • 62
0
votes
0 answers

Unable to send traffic over RDMA

I have softROCE setup on SUSE Linux SP11. I am trying to validate the traffic over RXE device. I am able to send and receive traffic using ibv_*_pingpong. But for rping it is giving and error RDMA_CM_EVENT_UNREACHABLE, error -110. #rxe_cfg -l Name …
dhara
  • 1
  • 3
1 2 3
…
11
12