Commit 54ab7d7c authored by Swapnil Sapkal's avatar Swapnil Sapkal Committed by Mario Limonciello
Browse files

amd-pstate: Switch to amd-pstate by default on some Server platforms 



Currently the default cpufreq driver for all the AMD EPYC servers is
acpi-cpufreq. Going forward, switch to amd-pstate as the default
driver on the AMD EPYC server platforms with CPU family 0x1A or
higher. The default mode will be active mode.

Testing shows that amd-pstate with active mode and performance
governor provides comparable or better performance per-watt against
acpi-cpufreq + performance governor.

Likewise, amd-pstate with active mode and powersave governor with the
energy_performance_preference=power (EPP=255) provides comparable or
better performance per-watt against acpi-cpufreq + schedutil governor
for a wide range of workloads.

Users can still revert to using acpi-cpufreq driver on these platforms
with the "amd_pstate=disable" kernel commandline parameter.

Signed-off-by: default avatarSwapnil Sapkal <swapnil.sapkal@amd.com>
Signed-off-by: default avatarGautham R. Shenoy <gautham.shenoy@amd.com>
Reviewed-by: default avatarMario Limonciello <mario.limonciello@amd.com>
Link: https://lore.kernel.org/r/20241021101836.9047-3-gautham.shenoy@amd.com


Signed-off-by: default avatarMario Limonciello <mario.limonciello@amd.com>
parent 0c411b39

drivers/cpufreq/amd-pstate.c

+2 −2
Original line number Diff line number Diff line
@@ -1832,10 +1832,10 @@ static int __init amd_pstate_init(void) 
	if (cppc_state == AMD_PSTATE_UNDEFINED) {

		/* Disable on the following configs by default:

		 * 1. Undefined platforms

		 * 2. Server platforms

		 * 2. Server platforms with CPUs older than Family 0x1A.

		 */

		if (amd_pstate_acpi_pm_profile_undefined() ||

		    amd_pstate_acpi_pm_profile_server()) {

		    (amd_pstate_acpi_pm_profile_server() && boot_cpu_data.x86 < 0x1A)) {

			pr_info("driver load is disabled, boot with specific mode to enable this\n");

			return -ENODEV;

		}