lkml.org 
[lkml]   [2019]   [Jun]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH v2] RDMA/cma: Make CM response timeout and # CM retries configurable
    On Thu, Jun 13, 2019 at 06:58:30PM +0200, Håkon Bugge wrote:

    > If you refer to the backlog parameter in rdma_listen(), I cannot see
    > it being used at all for IB.
    >
    > For CX-3, which is paravirtualized wrt. MAD packets, it is the proxy
    > UD receive queue length for the PF driver that can be construed as a
    > backlog.

    No, in IB you can drop UD packets if your RQ is full - so the proxy RQ
    is really part of the overall RQ on QP1.

    The backlog starts once packets are taken off the RQ and begin the
    connection accept processing.

    > Customer configures #VMs and different workload may lead to way
    > different number of CM connections. The proxying of MAD packet
    > through the PF driver has a finite packet rate. With 64 VMs, 10.000
    > QPs on each, all going down due to a switch failing or similar, you
    > have 640.000 DREQs to be sent, and with the finite packet rate of MA
    > packets through the PF, this takes more than the current CM
    > timeout. And then you re-transmit and increase the burden of the PF
    > proxying.

    I feel like the performance of all this proxying is too low to support
    such a large work load :(

    Can it be improved?

    Jason

    \
     
     \ /
      Last update: 2019-06-13 19:25    [W:4.821 / U:0.428 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site