Improve performance and idle power consumption
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
AMD |
Fix Released
|
Undecided
|
Alex Hung | ||
linux-oem-5.14 (Ubuntu) |
Invalid
|
Undecided
|
Unassigned | ||
Focal |
Fix Released
|
Undecided
|
Unassigned |
Bug Description
[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:/
[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:/
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?
Changed in amd: | |
assignee: | nobody → Alex Hung (alexhung) |
information type: | Proprietary → Public |
description: | updated |
Changed in linux-oem-5.14 (Ubuntu): | |
status: | New → Invalid |
Changed in linux-oem-5.14 (Ubuntu Focal): | |
status: | New → Fix Committed |
tags: |
added: verification-done-focal removed: verification-needed-focal |
Changed in amd: | |
status: | New → Fix Committed |
Changed in amd: | |
status: | Fix Committed → Fix Released |
Changed in amd: | |
status: | Fix Released → In Progress |
Changed in amd: | |
status: | In Progress → Fix Released |
I tried this on a Ryzen 5 2500U but couldn't see any differences. That was the only AMD system I can have physical access at the moment.
Which CPU or platform is supported by this patch?