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| author | Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> | 2020-06-26 11:34:00 -0700 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2020-07-02 13:02:46 +0200 |
| commit | ed7bde7a6dab521ee9e28fe2264018f83d83c7fa (patch) | |
| tree | bad397fef297f8f82bd56102d2363b3f084a6335 /arch/x86/include/asm/msr-index.h | |
| parent | 9ebcfadb0610322ac537dd7aa5d9cbc2b2894c68 (diff) | |
| download | linux-ed7bde7a6dab521ee9e28fe2264018f83d83c7fa.tar.bz2 | |
cpufreq: intel_pstate: Allow enable/disable energy efficiency
By default intel_pstate the driver disables energy efficiency by setting
MSR_IA32_POWER_CTL bit 19 for Kaby Lake desktop CPU model in HWP mode.
This CPU model is also shared by Coffee Lake desktop CPUs. This allows
these systems to reach maximum possible frequency. But this adds power
penalty, which some customers don't want. They want some way to enable/
disable dynamically.
So, add an additional attribute "energy_efficiency" under
/sys/devices/system/cpu/intel_pstate/ for these CPU models. This allows
to read and write bit 19 ("Disable Energy Efficiency Optimization") in
the MSR IA32_POWER_CTL.
This attribute is present in both HWP and non-HWP mode as this has an
effect in both modes. Refer to Intel Software Developer's manual for
details.
The scope of this bit is package wide. Also these systems are single
package systems. So read/write MSR on the current CPU is enough.
The energy efficiency (EE) bit setting needs to be preserved during
suspend/resume and CPU offline/online operation. To do this:
- Restoring the EE setting from the cpufreq resume() callback, if there
is change from the system default.
- By default, don't disable EE from cpufreq init() callback for matching
CPU models. Since the scope is package wide and is a single package
system, move the disable EE calls from init() callback to
intel_pstate_init() function, which is called only once.
Suggested-by: Len Brown <lenb@kernel.org>
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'arch/x86/include/asm/msr-index.h')
| -rw-r--r-- | arch/x86/include/asm/msr-index.h | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h index e8370e64a155..21b409195b46 100644 --- a/arch/x86/include/asm/msr-index.h +++ b/arch/x86/include/asm/msr-index.h @@ -149,6 +149,10 @@ #define MSR_LBR_SELECT 0x000001c8 #define MSR_LBR_TOS 0x000001c9 + +#define MSR_IA32_POWER_CTL 0x000001fc +#define MSR_IA32_POWER_CTL_BIT_EE 19 + #define MSR_LBR_NHM_FROM 0x00000680 #define MSR_LBR_NHM_TO 0x000006c0 #define MSR_LBR_CORE_FROM 0x00000040 @@ -253,8 +257,6 @@ #define MSR_PEBS_FRONTEND 0x000003f7 -#define MSR_IA32_POWER_CTL 0x000001fc - #define MSR_IA32_MC0_CTL 0x00000400 #define MSR_IA32_MC0_STATUS 0x00000401 #define MSR_IA32_MC0_ADDR 0x00000402 |