| 2021-08-27 13:17:53 |
Mario Limonciello |
bug |
|
|
added bug |
| 2021-09-02 13:46:51 |
Alex Hung |
amd: assignee |
|
Alex Hung (alexhung) |
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| 2021-10-08 20:45:14 |
Alex Hung |
information type |
Proprietary |
Public |
|
| 2021-10-08 20:56:38 |
Alex Hung |
description |
A patch queued for 5.15 to change the C3 entry will improve AMD performance.
https://lore.kernel.org/patchwork/patch/1478776/
Empirical measurements show:
40-45% improvement in speedometer score.
~15% improvement in idle power.
Can you please include in 5.13-oem and 5.14-oem kernels? |
[Impact]
This can improve AMD performance for all Zen or newer CPU which support C3 shares cache.
[Fix]
Its not necessary to flush the caches in software before entering C3.
Empirical measurements show:
40-45% improvement in speedometer score.
~15% improvement in idle power.
The patch is in linux-next (tag next-20211007) and can be found @ https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/arch/x86/kernel/acpi/cstate.c?id=a8fb40966f19ff81520d9ccf8f7e2b95201368b8
[Test]
This is requested by AMD.
[Where problems could occur]
Low risk. This only works on AMD Zen CPUs that supports this features. AMD tested it and provided estimated measurement results.
==== Original descriptions ====
A patch queued for 5.15 to change the C3 entry will improve AMD performance.
https://lore.kernel.org/patchwork/patch/1478776/
Empirical measurements show:
40-45% improvement in speedometer score.
~15% improvement in idle power.
Can you please include in 5.13-oem and 5.14-oem kernels? |
|
| 2021-10-25 16:45:35 |
Timo Aaltonen |
bug task added |
|
linux-oem-5.14 (Ubuntu) |
|
| 2021-10-25 17:01:38 |
Timo Aaltonen |
nominated for series |
|
Ubuntu Focal |
|
| 2021-10-25 17:01:38 |
Timo Aaltonen |
bug task added |
|
linux-oem-5.14 (Ubuntu Focal) |
|
| 2021-10-25 17:01:44 |
Timo Aaltonen |
linux-oem-5.14 (Ubuntu): status |
New |
Invalid |
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| 2021-10-25 17:01:47 |
Timo Aaltonen |
linux-oem-5.14 (Ubuntu Focal): status |
New |
Fix Committed |
|
| 2021-10-27 11:41:32 |
Ubuntu Kernel Bot |
tags |
|
verification-needed-focal |
|
| 2021-10-27 23:57:56 |
Alex Hung |
tags |
verification-needed-focal |
verification-done-focal |
|
| 2021-10-28 13:33:39 |
Amit Bhutani |
amd: status |
New |
Fix Committed |
|
| 2021-11-09 05:31:08 |
Launchpad Janitor |
linux-oem-5.14 (Ubuntu Focal): status |
Fix Committed |
Fix Released |
|
| 2021-11-09 20:56:53 |
Alex Hung |
amd: status |
Fix Committed |
Fix Released |
|
| 2022-01-06 22:24:59 |
Alex Hung |
amd: status |
Fix Released |
In Progress |
|
| 2022-02-04 00:01:03 |
Alex Hung |
amd: status |
In Progress |
Fix Released |
|
