The default EPP is set at 50%, which is deemed insufficiently
aggressive for meeting the MTL performance expectations in
balance_performance mode.
# cat /sys/devices/system/cpu/cpu0/cpufreq/energy_performance_preference
balance_performance
# iotools rdmsr 0 0x774
0x0000000080003f06
EPP=45% is giving the required performance in MTL.
# iotools rdmsr 0 0x774
0x0000000073003d06
NOTE: Kernel changes are necessary to ensure that the EPP (Energy Performance Preference) configured in the BIOS is not overwritten: https://patchwork.kernel.org/patch/13461932
BUG=b:314275133
TEST=Build and boot.
Change-Id: I1953994cdb4e9363fdd4b4728e3e5236276c06c8
Signed-off-by: Sukumar Ghorai <sukumar.ghorai@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/79386
Reviewed-by: Jakub Czapiga <czapiga@google.com>
Reviewed-by: Sumeet R Pawnikar <sumeet.r.pawnikar@intel.com>
Reviewed-by: Subrata Banik <subratabanik@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
1c295092d6