geopm::MSRIOGroup – IOGroup providing MSR-based signals and controls

Synopsis

Link with -lgeopmd

set<string> MSRIOGroup::signal_names(void) const override;

set<string> MSRIOGroup::control_names(void) const override;

bool MSRIOGroup::is_valid_signal(const string &signal_name) const override;

bool MSRIOGroup::is_valid_control(const string &control_name) const override;

int MSRIOGroup::signal_domain_type(const string &signal_name) const override;

int MSRIOGroup::control_domain_type(const string &control_name) const override;

int MSRIOGroup::push_signal(const string &signal_name,
                            int domain_type,
                            int domain_idx) override;

int MSRIOGroup::push_control(const string &control_name,
                             int domain_type,
                             int domain_idx) override;

void MSRIOGroup::read_batch(void) override;

void MSRIOGroup::write_batch(void) override;

double MSRIOGroup::sample(int sample_idx) override;

void MSRIOGroup::adjust(int control_idx,
                        double setting) override;

double MSRIOGroup::read_signal(const string &signal_name,
                               int domain_type,
                               int domain_idx) override;

void MSRIOGroup::write_control(const string &control_name,
                               int domain_type,
                               int domain_idx,
                               double setting) override;

void MSRIOGroup::save_control(void) override;

void MSRIOGroup::restore_control(void) override;

function<double(const vector<double> &)> MSRIOGroup::agg_function(const string &signal_name) const override;

function<string(double)> MSRIOGroup::format_function(const string &signal_name) const override;

string MSRIOGroup::signal_description(const string &signal_name) const override;

string MSRIOGroup::control_description(const string &control_name) const override;

int MSRIOGroup::signal_behavior(const string &signal_name) const override;

void MSRIOGroup::save_control(const string &save_path) override;

void MSRIOGroup::restore_control(const string &save_path) override;

string MSRIOGroup::name(void) const override;

void MSRIOGroup::parse_json_msrs(const string &str);

static string MSRIOGroup::msr_allowlist(int cpuid);

static int MSRIOGroup::cpuid(void);

static string MSRIOGroup::plugin_name(void);

static unique_ptr<IOGroup> MSRIOGroup::make_plugin(void);

Description

The MSRIOGroup implements the geopm::IOGroup(3) interface to provide hardware signals and controls using MSRs on Intel platforms. It relies on geopm_pio_msr(7) and geopm::MSRIO(3).

Class Methods

signal_names(): Returns the list of signal names provided by this IOGroup. This includes aliases for common hardware-based signals such as CPU_FREQUENCY_STATUS, as well as the supported MSRs for the current platform.
control_names(): Returns the list of control names provided by this IOGroup. This includes aliases for common hardware-based controls such as CPU_FREQUENCY_MAX_CONTROL, as well as the supported MSRs for the current platform.
is_valid_signal(): Returns whether the given signal_name is supported by the MSRIOGroup for the current platform. Note that different platforms may have different supported MSRs.
is_valid_control(): Returns whether the given control_name is supported by the MSRIOGroup for the current platform. Note that different platforms may have different supported MSRs.
signal_domain_type(): Returns the domain type for the signal specified by signal_name. The domain for a signal may be different on different platforms.
control_domain_type(): Returns the domain type for the control specified by control_name. The domain for a control may be different on different platforms.
push_signal(): Adds the signal specified by signal_name for domain_type at index domain_idx to the list of signals to be read during read_batch(). If the domain of a signal spans multiple Linux logical CPUs, only one CPU from that domain will be read, since all CPUs from the same domain and index will return the same value.
push_control(): Adds the control specified by control_name for domain_type at index domain_idx to the list of controls to be written during write_batch(). If the domain of a control spans multiple Linux logical CPUs, values written to that control will be written to all CPUs in the domain.
read_batch(): Sets up geopm::MSRIO(3) for batch reading if needed, then reads all pushed signals through the MSRIO::read_batch() method.
write_batch(): Writes all adjusted values through the geopm::MSRIO(3) write_batch() method.
sample(): Returns the value of the signal specified by a sample_idx returned from push_signal(). The value will have been updated by the most recent call to read_batch().
adjust(): Sets the control specified by a control_idx returned from push_control() to the value setting. The value will be written to the underlying MSR by the next call to write_batch().
read_signal(): Immediately read and decode the underlying MSR supporting signal_name for domain_type at index domain_idx and return the result in SI units.
write_control(): Immediately encode the SI unit value setting and write the correct bits of the MSR supporting control_name for domain_type at domain_idx.
save_control(): Attempts to read and save the current values of all control MSRs for the platform. If any control is not able to be read, it will be skipped.
restore_control(): Using the values saved by save_control(), attempts to write back the original values of all control MSRs. Any control that is not able to be written will be skipped.
agg_function(): Returns the function that should be used to aggregate signal_name. If one was not previously specified by this class, the default function is select_first() from geopm::Agg(3). Throws an exception if the signal_name is not valid.
format_function(): Returns the function that should be used to format the signal_name. If the signal_name string ends with a '#' character, the function returned is string_format_raw64(). Throws an exception if the signal_name is not valid or if the signal_name was not found.
signal_description(): Returns a string description for signal_name, if defined. Further descriptions of MSR signals can be found in The Intel Software Developer’s Manual
control_description(): Returns a string description for control_name, if defined. Further descriptions of MSR controls can be found in The Intel Software Developer’s Manual
signal_behavior(): Returns one of the IOGroup::signal_behavior_e values which describes about how a signal will change as a function of time. This can be used when generating reports to decide how to summarize a signal’s value for the entire application run.
parse_json_msrs(): Parse a JSON string and add any raw MSRs and fields as available signals and controls.
name(): Calls plugin_name() internally.
msr_allowlist(): Fill string with the msr-safe allowlist file contents reflecting all known MSRs for the current platform, or if cpuid is provided, for the platform specified by cpuid. Returns a string formatted to be written to an msr-safe allowlist file.
cpuid(): Get the cpuid of the current platform.
plugin_name(): Returns the name of the plugin to use when this plugin is registered with the IOGroup factory; see geopm::PluginFactory(3) for more details.
make_plugin(): Returns a pointer to a new MSRIOGroup object; see geopm::PluginFactory(3) for more details.

Enum Type

enum m_cpuid_e {
    M_CPUID_SNB = 0x62D,
    M_CPUID_IVT = 0x63E,
    M_CPUID_HSX = 0x63F,
    M_CPUID_BDX = 0x64F,
    M_CPUID_KNL = 0x657,
    M_CPUID_SKX = 0x655,
    M_CPUID_ICX = 0x66A,
};

enum m_cpuid_e: Contains the list of currently-supported cpuid values. The cpuid can be determined by running lscpu and appending the CPU family in hex to the Model in hex.

Environment

If the GEOPM_MSR_CONFIG_PATH environment variable is set to a colon-separated list of paths, the paths will be checked for files starting with msr_ and ending in .json. The /etc/geopm directory will also be searched. The MSRIOGroup will attempt to load additional MSR definitions from any JSON file it finds. The files must follow this schema:

{
    "$schema": "http://json-schema.org/draft-04/schema#",
    "id": "https://geopm.github.io/msrs.schema.json",
    "title": "MSR specification",
    "definitions" : {
      "msrFields": {
        "type": "object",
        "properties": {
          "begin_bit": {
            "type": "integer"
          },
          "end_bit": {
            "type": "integer"
          },
          "function": {
            "enum": ["scale", "log_half", "7_bit_float", "overflow", "logic"]
          },
          "units": {
            "enum": ["none", "seconds", "hertz", "watts", "joules", "celsius", "amperes", "volts"]
          },
          "scalar": {
            "type": "number"
          },
          "behavior": {
            "enum": ["constant", "monotone", "variable", "label"]
          },
          "writeable": {
            "type": "boolean"
          },
          "aggregation": {
            "enum": ["sum", "average", "median", "logical_and", "logical_or", "region_hash", "region_hint", "min", "max", "stddev", "select_first", "expect_same"]
          },
          "description": {
            "type": "string"
          }
        },
        "required": ["begin_bit", "end_bit", "function", "scalar", "units", "writeable", "behavior", "aggregation"],
        "additionalProperties": false
      },
      "msrObject": {
        "type": "object",
        "properties": {
          "offset": {
            "type": "string"
          },
          "domain": {
            "enum": ["board", "package", "core", "cpu", "memory", "package_integrated_memory", "nic", "package_integrated_nic", "gpu", "package_integrated_gpu", "gpu_chip"]
          },
          "fields": {
            "type": "object",
            "additionalProperties": {
              "$ref": "#/definitions/msrFields"
            }
          }
        },
        "required": ["offset", "domain", "fields"],
        "additionalProperties": false
      }
    },
    "type": "object",
    "properties": {
      "msrs": {
        "type": "object",
        "additionalProperties": {
          "$ref": "#/definitions/msrObject"
        }
      }
    },
    "additionalProperties": false
}