** 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 <gk...@linux.vnet.ibm.com>
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
--
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/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 <gk...@linux.vnet.ibm.com>
Date: Wed Oct 15 12:42:58 2014 +0200
powerpc/vphn: NUMA node code expects big-endian
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