This bug was fixed in the package linux - 6.2.0-18.18
---------------
linux (6.2.0-18.18) lunar; urgency=medium
* lunar/linux: 6.2.0-18.18 -proposed tracker (LP: #2011750)
* lunar/linux 6.2 fails to boot on arm64 (LP: #2011748)
- SAUCE: Revert "efi: random: fix NULL-deref when refreshing seed"
- SAUCE: Revert "efi: random: refresh non-volatile random seed when RNG is
initialized"
-- Andrea Righi <[email protected]> Wed, 15 Mar 2023 23:54:18
+0100
** Changed in: linux (Ubuntu Lunar)
Status: Fix Committed => Fix Released
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https://bugs.launchpad.net/bugs/2008519
Title:
cpufreq: intel_pstate: Update Balance performance EPP for Sapphire
Rapids
Status in intel:
Fix Released
Status in linux package in Ubuntu:
Fix Released
Status in linux source package in Jammy:
Fix Committed
Status in linux source package in Kinetic:
Fix Committed
Status in linux source package in Lunar:
Fix Released
Bug description:
[SRU Justification]
== Impact ==
See original description. The goal is to adjust the behavior of the balanced
governor for certain Xeon CPUs (those are CPUs rather seen in servers so there
should be no impact on laptop users). While the initial request was Jammy/5.15
only we should do this to Kinetic and Lunar as well so the experience is the
same regardless of release.
== Fix ==
This picks one change from v6.3-rc1 which tweaks the intel_idle driver for a
specific CPU model. For Jammy/5.15 this requires one additional change
which introduces the EPP tweak for Alderlake.
== Test case ==
<TBD one of the artificial workloads to compare before and after>
== Regression Potential ==
The change modifies how quickly CPUs scale up (and probably down) depending
on workload. Power usage unlikely is of that much concern in server space.
Maybe increased heat would be observed.
For Jammy there is the additional risk of havind a different power usage
on Alderlake which is a Laptop CPU. However that change is part of v5.17
and thus would already be in effect with current 22.04 HWE.
== Original description ==
[Feature Description]
Ubuntu uses powersave governor as the default.While the powersave governor
has much lower power, the performance is lower than +25% for several workloads
compared to performance governor.
Report is published: www.Phoronix.com showing difference of 37%
The goal here is to keep mean performance delta of powersave governor
from performance governor around 10% to 12% by running wide variety
of server workloads. For some bursty workload, this delta can be still
large, as ramp up of frequency will still lag with powersave governor
irrespective of EPP setting. The performance governor always requests
maximum frequency.
Based on experiments, EPP of 0x00, 0x10, 0x20, the performance delta for
powersave governor is around 12%. But the EPP 0x20 has 18% lower average
power.
Also experiments are done by raising intel_pstate sysfs min_perf_pct as
high as 50%. This didn't bring in any additional improvements compared
to just changing EPP.
Target Kernel: 6.3
Target Release: 22.04 (5.15 kernel)
[HW/SW Information]
Sapphire Rapids
[Business Justification]
Performance Improvements
Upstream: Merged 6.3
Commit ID: 60675225ebeecea248035fd3a0efc82ae9038a98
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