when using write op with more than 1024B(MTU) in softroce mode,the operation fail

when write message length is more than 1024B(mtu), it failed in softroce mode, pls help check why.

using the standard tool ib_write_lat to test: when ib_write_lat -s 1024 -n 5 when ib_write_lat -s 1025 -n 5, it fail.

my softroce version in in “Red Hat Enterprise Linux Server release 7.4 (Maipo)”

Is it a bug in softroce? Thanks!

Hi Tianyu,

Have you properly configured Soft-Roce whether upstream or Mellanox OFED Driver.

See reference links below:

HowTo Configure Soft-RoCE https://community.mellanox.com/s/article/howto-configure-soft-roce

How to configure Soft-RoCE with Mellanox OFED 4.x

Also, you original statement is confusing or contradicting itself:

when my write opcode with length=1024, it is ok. but when length=1025 in the same code, it will fail.

when the same code with length=1024 or 1025 run using mellanox CX4 card, it is ok >>> Apparently working.


Dear Tianyu

I have the same problem, any RDMA WR that is bigger than 1 MTU (1024B) fails on SoftROCE between two virtual machines in Virtualbox. (CentOS 7.4.1708, rdma-core-22.1-3.el7.x86_64 )

All examples i have tried (and my own code) fail at the same point so it looks like this is a problem with the driver somehow…

Did you get an answer ?