$ tree /sys/devices/system/cpu/cpu0/
/sys/devices/system/cpu/cpu0/
├── cache
│   ├── index0
│   ├── ...
│   ├── index3
│   └── uevent
├── cpufreq -> ../cpufreq/policy0
├── cpuidle
│   ├── state0
│   │   ├── above
│   │   ├── below
│   │   ├── default_status
│   │   ├── desc
│   │   ├── disable
│   │   ├── latency
│   │   ├── name
│   │   ├── power
│   │   ├── rejected
│   │   ├── residency
│   │   ├── time
│   │   └── usage
│   └── state1
│       ├── above
│       ├── below
│       ├── default_status
│       ├── desc
│       ├── disable
│       ├── latency
│       ├── name
│       ├── power
│       ├── rejected
│       ├── residency
│       ├── time
│       └── usage
├── crash_notes
├── crash_notes_size
├── driver -> ../../../../bus/cpu/drivers/processor
├── firmware_node -> ../../../LNXSYSTM:00/LNXCPU:00
├── hotplug
│   ├── fail
│   ├── state
│   └── target
├── node0 -> ../../node/node0
├── power
│   ├── async
│   ├── autosuspend_delay_ms
│   ├── control
│   ├── pm_qos_resume_latency_us
│   ├── runtime_active_kids
│   ├── runtime_active_time
│   ├── runtime_enabled
│   ├── runtime_status
│   ├── runtime_suspended_time
│   └── runtime_usage
├── subsystem -> ../../../../bus/cpu
├── topology
│   ├── cluster_cpus
│   ├── cluster_cpus_list
│   ├── cluster_id
│   ├── core_cpus
│   ├── core_cpus_list
│   ├── core_id
│   ├── core_siblings
│   ├── core_siblings_list
│   ├── die_cpus
│   ├── die_cpus_list
│   ├── die_id
│   ├── package_cpus
│   ├── package_cpus_list
│   ├── physical_package_id
│   ├── thread_siblings
│   └── thread_siblings_list
└── uevent

$ tree /sys/devices/system/cpu/cpu0/cpufreq/
/sys/devices/system/cpu/cpu0/cpufreq/
├── affected_cpus
├── cpuinfo_max_freq
├── cpuinfo_min_freq
├── cpuinfo_transition_latency
├── related_cpus
├── scaling_available_governors
├── scaling_cur_freq
├── scaling_driver
├── scaling_governor
├── scaling_max_freq
├── scaling_min_freq
└── scaling_setspeed

$ tree /sys/devices/system/cpu/cpu0/cpuidle/
/sys/devices/system/cpu/cpu0/cpuidle/
├── state0
│   ├── above
│   ├── below
│   ├── default_status
│   ├── desc
│   ├── disable
│   ├── latency
│   ├── name
│   ├── power
│   ├── rejected
│   ├── residency
│   ├── time
│   └── usage
├── state1
│   ├── above
│   ├── below
│   ├── default_status
│   ├── desc
│   ├── disable
│   ├── latency
│   ├── name
│   ├── power
│   ├── rejected
│   ├── residency
│   ├── s2idle
│   │   ├── time
│   │   └── usage
│   ├── time
│   └── usage
│...

$ tree /sys/devices/system/cpu/cpu0/
/sys/devices/system/cpu/cpu0/
├── power
│   ├── async
│   ├── autosuspend_delay_ms
│   ├── control
│   ├── pm_qos_resume_latency_us
│   ├── runtime_active_kids
│   ├── runtime_active_time
│   ├── runtime_enabled
│   ├── runtime_status
│   ├── runtime_suspended_time
│   └── runtime_usage

$ tree /sys/devices/system/cpu/cpu0/
/sys/devices/system/cpu/cpu0/
├── topology
│   ├── cluster_cpus
│   ├── cluster_cpus_list
│   ├── cluster_id
│   ├── core_cpus
│   ├── core_cpus_list
│   ├── core_id
│   ├── core_siblings
│   ├── core_siblings_list
│   ├── die_cpus
│   ├── die_cpus_list
│   ├── die_id
│   ├── package_cpus
│   ├── package_cpus_list
│   ├── physical_package_id
│   ├── thread_siblings
│   └── thread_siblings_list
└── uevent

$ ls /sys/devices/system/cpu/cpuidle/
available_governors  current_driver  current_governor  current_governor_ro

$ cat /sys/devices/system/cpu/cpuidle/available_governors
menu
$ cat /sys/devices/system/cpu/cpuidle/current_driver
acpi_idle
$ cat /sys/devices/system/cpu/cpuidle/current_governor
menu

// https://github.com/torvalds/linux/blob/v5.15/Documentation/admin-guide/kernel-parameters.txt

    idle=        [X86]
            Format: idle=poll, idle=halt, idle=nomwait

            1. idle=poll forces a polling idle loop that can slightly improve the performance of waking up a
               idle CPU, but will use a lot of power and make the system run hot. Not recommended.
            2. idle=halt: Halt is forced to be used for CPU idle. In such case C2/C3 won't be used again.
            3. idle=nomwait: Disable mwait for CPU C-states

// https://github.com/torvalds/linux/blob/v5.15/Documentation/admin-guide/kernel-parameters.txt#L1988

	intel_pstate=	[X86]
			disable
			  Do not enable intel_pstate as the default
			  scaling driver for the supported processors
			passive
			  Use intel_pstate as a scaling driver, but configure it
			  to work with generic cpufreq governors (instead of
			  enabling its internal governor).  This mode cannot be
			  used along with the hardware-managed P-states (HWP)
			  feature.
			force
			  Enable intel_pstate on systems that prohibit it by default
			  in favor of acpi-cpufreq. Forcing the intel_pstate driver
			  instead of acpi-cpufreq may disable platform features, such
			  as thermal controls and power capping, that rely on ACPI
			  P-States information being indicated to OSPM and therefore
			  should be used with caution. This option does not work with
			  processors that aren't supported by the intel_pstate driver
			  or on platforms that use pcc-cpufreq instead of acpi-cpufreq.
			no_hwp
			  Do not enable hardware P state control (HWP)
			  if available.
			hwp_only
			  Only load intel_pstate on systems which support
			  hardware P state control (HWP) if available.
			support_acpi_ppc
			  Enforce ACPI _PPC performance limits. If the Fixed ACPI
			  Description Table, specifies preferred power management
			  profile as "Enterprise Server" or "Performance Server",
			  then this feature is turned on by default.
			per_cpu_perf_limits
			  Allow per-logical-CPU P-State performance control limits using
			  cpufreq sysfs interface

// https://github.com/torvalds/linux/blob/v5.15/Documentation/admin-guide/kernel-parameters.txt

	intel_idle.max_cstate=	[KNL,HW,ACPI,X86]
			0	disables intel_idle and fall back on acpi_idle.
			1 to 9	specify maximum depth of C-state.

	processor.max_cstate=	[HW,ACPI]
			Limit processor to maximum C-state
			max_cstate=9 overrides any DMI blacklist limit.

$ cat /proc/cpuinfo | awk '/cpu MHz/ { printf("cpu=%d freq=%s\n", i++, $NF)}'
cpu=0 freq=3393.622
cpu=1 freq=3393.622
cpu=2 freq=3393.622
cpu=3 freq=3393.622

$ tuned-adm list
Available profiles:
- balanced                    - General non-specialized tuned profile
- desktop                     - Optimize for the desktop use-case
- latency-performance         - Optimize for deterministic performance at the cost of increased power consumption
- network-latency             - Optimize for deterministic performance at the cost of increased power consumption, focused on low latency network performance
- network-throughput          - Optimize for streaming network throughput, generally only necessary on older CPUs or 40G+ networks
- powersave                   - Optimize for low power consumption
- throughput-performance      - Broadly applicable tuning that provides excellent performance across a variety of common server workloads
- virtual-guest               - Optimize for running inside a virtual guest
- virtual-host                - Optimize for running KVM guests
Current active profile: latency-performance

$ tuned-adm active
Current active profile: latency-performance

$ tuned-adm profile_info latency-performance
Profile name:
latency-performance

Profile summary:
Optimize for deterministic performance at the cost of increased power consumption

$ tuned-adm profile_mode
Profile selection mode: manual

turbostat - Report processor frequency and idle statistics
turbostat  reports processor topology, frequency, idle power-state statistics, temperature and power on X86 processors.

$ turbostat --quiet --hide sysfs,IRQ,SMI,CoreTmp,PkgTmp,GFX%rc6,GFXMHz,PkgWatt,CorWatt,GFXWatt
            Core CPU  Avg_MHz    Busy%     Bzy_MHz   TSC_MHz   CPU%c1    CPU%c3    CPU%c6    CPU%c7
            -    -    488        12.52     3900      3498      12.50     0.00      0.00      74.98
            0    0    5          0.13      3900      3498      99.87     0.00      0.00      0.00
            0    4    3897       99.99     3900      3498      0.01
            1    1    0          0.00      3856      3498      0.01      0.00      0.00      99.98
            1    5    0          0.00      3861      3498      0.01
            2    2    1          0.02      3889      3498      0.03      0.00      0.00      99.95
            2    6    0          0.00      3863      3498      0.05
            3    3    0          0.01      3869      3498      0.02      0.00      0.00      99.97
            3    7    0          0.00      3878      3498      0.03