kernel-packages team mailing list archive

[Tim Gardner <tim.gardner@xxxxxxxxxxxxx>]

https://lists.ubuntu.com/archives/kernel-team/2016-May/077794.html

** Changed in: linux (Ubuntu)
       Status: Incomplete => In Progress

** Changed in: linux (Ubuntu)
     Assignee: (unassigned) => Tim Gardner (timg-tpi)

** Also affects: linux (Ubuntu Yakkety)
   Importance: Undecided
     Assignee: Tim Gardner (timg-tpi)
       Status: In Progress

** Also affects: linux (Ubuntu Xenial)
   Importance: Undecided
       Status: New

** Changed in: linux (Ubuntu Xenial)
       Status: New => In Progress

** Changed in: linux (Ubuntu Xenial)
     Assignee: (unassigned) => Tim Gardner (timg-tpi)

** Changed in: linux (Ubuntu Yakkety)
       Status: In Progress => Fix Committed

-- 
You received this bug notification because you are a member of Kernel
Packages, which is subscribed to linux in Ubuntu.
https://bugs.launchpad.net/bugs/1585850

Title:
  [Bug]KNL:Spread MWAIT cache lines over all nodes

Status in intel:
  New
Status in linux package in Ubuntu:
  Fix Committed
Status in linux source package in Xenial:
  In Progress
Status in linux source package in Yakkety:
  Fix Committed

Bug description:
  KNL sees severely degraded memory bandwidth on MCDRAM with C-states deeper than C1 and with sub numa clustering enabled. This has been root caused to all idle task's MWAIT cache line placed in node 0. Node 0's CHA goes into degraded mode because the many MWAIT lines overflow an internal hash table.
  Fix is to allocate the idle task's task structs on their respective nodes.

  The fix patch is merged into linux-next and will be part of v4.7,
  please back port into 16.04 kernel:

  725fc62 kernek/fork.c: allocate idle task for a CPU always on its
  local node

To manage notifications about this bug go to:
https://bugs.launchpad.net/intel/+bug/1585850/+subscriptions