| 2018-07-13 04:39:12 |
bugproxy |
bug |
|
|
added bug |
| 2018-07-13 04:39:14 |
bugproxy |
tags |
|
architecture-ppc64le bugnameltc-169712 severity-high targetmilestone-inin1804 |
|
| 2018-07-13 04:39:15 |
bugproxy |
ubuntu: assignee |
|
Ubuntu on IBM Power Systems Bug Triage (ubuntu-power-triage) |
|
| 2018-07-13 04:39:19 |
bugproxy |
affects |
ubuntu |
qemu (Ubuntu) |
|
| 2018-07-13 05:20:58 |
Frank Heimes |
tags |
architecture-ppc64le bugnameltc-169712 severity-high targetmilestone-inin1804 |
architecture-ppc64le bugnameltc-169712 severity-high targetmilestone-inin1804 triage-g |
|
| 2018-07-13 05:21:22 |
Frank Heimes |
bug task added |
|
ubuntu-power-systems |
|
| 2018-07-13 05:21:32 |
Frank Heimes |
ubuntu-power-systems: importance |
Undecided |
High |
|
| 2018-07-13 05:21:49 |
Frank Heimes |
ubuntu-power-systems: assignee |
|
Canonical Server Team (canonical-server) |
|
| 2018-07-13 05:22:18 |
Frank Heimes |
bug |
|
|
added subscriber Christian Ehrhardt |
| 2018-07-16 07:03:21 |
Christian Ehrhardt |
nominated for series |
|
Ubuntu Bionic |
|
| 2018-07-16 07:03:21 |
Christian Ehrhardt |
bug task added |
|
qemu (Ubuntu Bionic) |
|
| 2018-07-16 07:03:26 |
Christian Ehrhardt |
qemu (Ubuntu Bionic): status |
New |
Triaged |
|
| 2018-07-16 07:03:28 |
Christian Ehrhardt |
qemu (Ubuntu): status |
New |
In Progress |
|
| 2018-07-16 07:26:48 |
Frank Heimes |
ubuntu-power-systems: status |
New |
Triaged |
|
| 2018-07-16 09:33:34 |
Launchpad Janitor |
merge proposal linked |
|
https://code.launchpad.net/~paelzer/ubuntu/+source/qemu/+git/qemu/+merge/348575 |
|
| 2018-07-16 14:15:08 |
Manoj Iyer |
qemu (Ubuntu): assignee |
Ubuntu on IBM Power Systems Bug Triage (ubuntu-power-triage) |
David Britton (davidpbritton) |
|
| 2018-07-16 14:15:20 |
Manoj Iyer |
qemu (Ubuntu Bionic): assignee |
|
David Britton (davidpbritton) |
|
| 2018-07-16 14:15:23 |
Manoj Iyer |
qemu (Ubuntu): importance |
Undecided |
High |
|
| 2018-07-16 14:15:25 |
Manoj Iyer |
qemu (Ubuntu Bionic): importance |
Undecided |
High |
|
| 2018-07-16 18:19:53 |
Launchpad Janitor |
merge proposal unlinked |
https://code.launchpad.net/~paelzer/ubuntu/+source/qemu/+git/qemu/+merge/348575 |
|
|
| 2018-07-20 07:37:05 |
Launchpad Janitor |
qemu (Ubuntu): status |
In Progress |
Fix Released |
|
| 2018-11-05 15:21:43 |
Manoj Iyer |
qemu (Ubuntu Bionic): assignee |
David Britton (davidpbritton) |
|
|
| 2018-11-05 15:21:49 |
Manoj Iyer |
qemu (Ubuntu): assignee |
David Britton (davidpbritton) |
|
|
| 2018-11-26 14:51:26 |
Frank Heimes |
ubuntu-power-systems: status |
Triaged |
Incomplete |
|
| 2018-11-29 13:41:34 |
Christian Ehrhardt |
qemu (Ubuntu Bionic): status |
Triaged |
Incomplete |
|
| 2019-01-07 11:17:27 |
Christian Ehrhardt |
qemu (Ubuntu Bionic): status |
Incomplete |
Won't Fix |
|
| 2019-01-07 11:38:22 |
Andrew Cloke |
ubuntu-power-systems: status |
Incomplete |
Won't Fix |
|
| 2019-04-03 09:02:39 |
Christian Ehrhardt |
qemu (Ubuntu Bionic): status |
Won't Fix |
Incomplete |
|
| 2019-04-03 09:10:45 |
Christian Ehrhardt |
description |
== Comment: #0 - JENIFER HOPPER <jhopper@us.ibm.com> - 2018-07-12 11:41:50 ==
---Problem Description---
We would like to request the following simple qemu patch be applied because it can provide significant performance improvements for Power9 KVM guests that benefit from 2MB THP usage:
commit 0c1272cc7c72dfe0ef66be8f283cf67c74b58586
osdep: powerpc64 align memory to allow 2MB radix THP page tables
This allows KVM with the Book3S radix MMU mode to take advantage of
THP and install larger pages in the partition scope page tables (the
host translation).
--
For instance, when THP is enabled I measured a 10% throughput improvement with this patch for a full system P9 Radix guest running the SPECjbb2005 workload.
Contact Information = jhopper@us.ibm.com
---uname output---
Linux perfwsp6 4.15.0-20-generic #21-Ubuntu SMP Tue Apr 24 06:14:44 UTC 2018 ppc64le ppc64le ppc64le GNU/Linux
Machine Type = 8335-GTH
---Debugger---
A debugger is not configured
---Steps to Reproduce---
Run a workload that benefits from THP usage in a P9 KVM guest. |
[Impact]
* Memory on ppc64el was only aligned at pagesize, but for THP to benefit
aligning on 2MB would be beneficial for translations (performance)
[Test Case]
* It was reported that running specjbb2005 in guests on a P9 system can
gain up to 10% performance. Therefore running that with a guest that
workload (guest pinned, THP set to always) would be the test that shall
be done (on a non shared performance capable machine). IBM committed to
verify the PPA and eventually the SRU with such a setup (or
comparable).
[Fix]
* Backport https://git.qemu.org/?p=qemu.git;a=commit;h=0c1272cc7c72dfe0ef66be8f283cf67c74b58586
[Regression Potential]
* It adds a PPC64 check for the alignment, that does not change any other
architectures (unless this one line change is wrong). The change runs
fine in later versions and is requested by IBM owning the ppc64el arch.
The effect should be just some speedup by THP being able to pick up
some more memory. As we have seen (comment #8) side effects are
possible, but all that are known are sorted out now.
[Other Info]
* This was postponed for a while as the change would have made another
issue more likely. But that is now fixed (in the kernel), so we can go
on.
--- original bug ---
== Comment: #0 - JENIFER HOPPER <jhopper@us.ibm.com> - 2018-07-12 11:41:50 ==
---Problem Description---
We would like to request the following simple qemu patch be applied because it can provide significant performance improvements for Power9 KVM guests that benefit from 2MB THP usage:
commit 0c1272cc7c72dfe0ef66be8f283cf67c74b58586
osdep: powerpc64 align memory to allow 2MB radix THP page tables
This allows KVM with the Book3S radix MMU mode to take advantage of
THP and install larger pages in the partition scope page tables (the
host translation).
--
For instance, when THP is enabled I measured a 10% throughput improvement with this patch for a full system P9 Radix guest running the SPECjbb2005 workload.
Contact Information = jhopper@us.ibm.com
---uname output---
Linux perfwsp6 4.15.0-20-generic #21-Ubuntu SMP Tue Apr 24 06:14:44 UTC 2018 ppc64le ppc64le ppc64le GNU/Linux
Machine Type = 8335-GTH
---Debugger---
A debugger is not configured
---Steps to Reproduce---
Run a workload that benefits from THP usage in a P9 KVM guest. |
|
| 2019-04-03 09:27:21 |
Frank Heimes |
ubuntu-power-systems: status |
Won't Fix |
Incomplete |
|
| 2019-05-30 15:44:58 |
Manoj Iyer |
ubuntu-power-systems: importance |
High |
Medium |
|
| 2019-05-30 15:45:03 |
Manoj Iyer |
qemu (Ubuntu Bionic): importance |
High |
Medium |
|
| 2019-07-22 14:22:38 |
Manoj Iyer |
qemu (Ubuntu): importance |
High |
Medium |
|
| 2019-07-22 14:23:05 |
Manoj Iyer |
ubuntu-power-systems: assignee |
Canonical Server Team (canonical-server) |
|
|
| 2019-09-27 05:47:46 |
Christian Ehrhardt |
qemu (Ubuntu Bionic): status |
Incomplete |
Won't Fix |
|
| 2019-09-27 06:46:22 |
Andrew Cloke |
ubuntu-power-systems: status |
Incomplete |
Fix Released |
|
