garnet/bin/power_manager/src/message.rs

// Copyright 2019 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

use crate::types::{Celsius, ThermalLoad, Watts};

/// Defines the message types and arguments to be used for inter-node communication
#[derive(Debug, PartialEq, PartialOrd)]
#[allow(dead_code)]
pub enum Message {
    /// Read the temperature
    ReadTemperature,

    /// Get the number of CPUs in the system
    GetNumCpus,

    /// Get the total CPU load which is the sum of the load of all CPUs in the system. Per-CPU load
    /// is reported as a value between 0.0 - 1.0 and is calculated by dividing the total time a
    /// CPU spent not idle during a duration by the total time elapsed during the same duration,
    /// where the duration is defined as the time since the previous GetTotalCpuLoad call. The
    /// first call returns a load of 0.0 because the time duration required to calculate load is
    /// undefined without a second call.
    GetTotalCpuLoad,

    /// Instruct the node to limit the power consumption of its corresponding component (e.g., CPU)
    /// Arg: the max number of watts that the component should be allowed to consume
    SetMaxPowerConsumption(Watts),

    /// Command a system shutdown
    /// Arg: a string specifying the reason for the shutdown, to be used for logging
    SystemShutdown(String),

    /// Instruct a node to update its thermal load value
    /// Arg: a ThermalLoad value which represents the severity of thermal load in the system
    UpdateThermalLoad(ThermalLoad),

    /// Get the current performance state
    GetPerformanceState,

    /// Set the new performance state
    /// Arg: a value in the range [0 - x] where x is an upper bound defined in the
    /// dev_control_handler crate. An increasing value indicates a lower performance state.
    SetPerformanceState(u32),

    /// File a crash report
    /// Arg: the crash report signature
    FileCrashReport(String),
}

/// Defines the return values for each of the Message types from above
#[derive(Debug)]
#[allow(dead_code)]
pub enum MessageReturn {
    /// Arg: temperature in Celsius
    ReadTemperature(Celsius),

    /// Arg: the number of CPUs in the system
    GetNumCpus(u32),

    /// Arg: the sum of the load from all CPUs in the system. The value is defined as
    /// 0.0 - [number_cpus]. The first call will return a load of 0.0.
    GetTotalCpuLoad(f32),

    /// Arg: the max number of watts that the component will use. This number should typically be at
    /// or below the number that was specified in the Message, but there may be cases where it
    /// actually exceeds that number (e.g., a CPU that cannot operate below the requested power
    /// level).
    SetMaxPowerConsumption(Watts),

    /// There is no arg in this MessageReturn type. It only serves as an ACK.
    SystemShutdown,

    /// There is no arg in this MessageReturn type. It only serves as an ACK.
    UpdateThermalLoad,

    /// Arg: the performance state returned from the node
    GetPerformanceState(u32),

    /// There is no arg in this MessageReturn type. It only serves as an ACK.
    SetPerformanceState,

    /// There is no arg in this MessageReturn type. It only serves as an ACK.
    FileCrashReport,
}