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[Chris J Arges <1401150@xxxxxxxxxxxxxxxxxx>]

** Changed in: linux (Ubuntu)
     Assignee: (unassigned) => Chris J Arges (arges)

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

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

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

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

** Changed in: linux (Ubuntu Trusty)
     Assignee: (unassigned) => Chris J Arges (arges)

** Changed in: linux (Ubuntu Utopic)
     Assignee: (unassigned) => Chris J Arges (arges)

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

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

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

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

** Description changed:

- -- Problem Description --
+ SRU Justification:
+ 
+ [Impact]
  The current VPHN code assumes the NUMA toplogy updates data are big endian. They are native endian actually since the hypervisor pass them through registers. This has a great performance impact on little endian guests.
+ 
+ [Test Case]
+ Install NUMA capable power8 machine in LE mode, install LE guest. Measure performance differences in LE guest after applying this patch.
+ 
+ [Fix]
+ commit 5c9fb1899400096c6818181c525897a31d57e488 upstream
+ in v3.18-rc2
  
  A fix has been sent to fix the issue:
  
  http://patchwork.ozlabs.org/patch/396171/
  
  Please pick the following commit from Michael Ellermans's tree:
  
  http://git.kernel.org/cgit/linux/kernel/git/mpe/linux.git/commit/?id=5c9fb1899400096c6818181c525897a31d57e488
  
  which reads: "powerpc/vphn: NUMA node code expects big-endian"
  
  Now upstream:
  
  commit 5c9fb1899400096c6818181c525897a31d57e488
  Author: Greg Kurz <gkurz@xxxxxxxxxxxxxxxxxx>
  Date:   Wed Oct 15 12:42:58 2014 +0200
  
-     powerpc/vphn: NUMA node code expects big-endian
+     powerpc/vphn: NUMA node code expects big-endian

-- 
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https://bugs.launchpad.net/bugs/1401150

Title:
  Endianness issue in the VPHN topology update code

Status in linux package in Ubuntu:
  In Progress
Status in linux source package in Trusty:
  In Progress
Status in linux source package in Utopic:
  In Progress

Bug description:
  SRU Justification:

  [Impact]
  The current VPHN code assumes the NUMA toplogy updates data are big endian. They are native endian actually since the hypervisor pass them through registers. This has a great performance impact on little endian guests.

  [Test Case]
  Install NUMA capable power8 machine in LE mode, install LE guest. Measure performance differences in LE guest after applying this patch.

  [Fix]
  commit 5c9fb1899400096c6818181c525897a31d57e488 upstream
  in v3.18-rc2

  A fix has been sent to fix the issue:

  http://patchwork.ozlabs.org/patch/396171/

  Please pick the following commit from Michael Ellermans's tree:

  http://git.kernel.org/cgit/linux/kernel/git/mpe/linux.git/commit/?id=5c9fb1899400096c6818181c525897a31d57e488

  which reads: "powerpc/vphn: NUMA node code expects big-endian"

  Now upstream:

  commit 5c9fb1899400096c6818181c525897a31d57e488
  Author: Greg Kurz <gkurz@xxxxxxxxxxxxxxxxxx>
  Date:   Wed Oct 15 12:42:58 2014 +0200

      powerpc/vphn: NUMA node code expects big-endian

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