kernel-packages team mailing list archive

[Joseph Salisbury <joseph.salisbury@xxxxxxxxxxxxx>]

** Changed in: linux (Ubuntu)
   Importance: Undecided => High

** Tags added: kernel-da-key xenial

** Tags added: needs-bisect

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https://bugs.launchpad.net/bugs/1536837

Title:
  Severe performance regression in Infiniband or IPoIB

Status in linux package in Ubuntu:
  Incomplete

Bug description:
  When upgrading to the latest 4.4 test kernel from mainline
  development, all IPoIB links showed a severe performance regression as
  compared with kernel 4.2.  The bandwidth of each link dropped from
  around 3Gbps to around 3Mbps (3 orders of magnitude worse!); reverting
  to the 4.2 kernel immediately fixed this problem.

  The 4.3 kernel from Debian does not appear to suffer from this
  regression.  The regression shows up on both IB ports of the Mellanox
  MT25208 controller.  Other hardware has not been tested.

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