src/sim/power/thermal_model.hh

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#ifndef __SIM_THERMAL_MODEL_HH__
#define __SIM_THERMAL_MODEL_HH__

#include <vector>

#include "base/temperature.hh"
#include "sim/clocked_object.hh"
#include "sim/power/thermal_domain.hh"
#include "sim/power/thermal_entity.hh"
#include "sim/power/thermal_node.hh"
#include "sim/sim_object.hh"

struct ThermalCapacitorParams;
struct ThermalModelParams;
struct ThermalReferenceParams;
struct ThermalResistorParams;

/**
 * A ThermalResistor is used to model a thermal resistance between two
 * thermal domains. This domains can be either a reference (fixed temp.) or
 * a heat producer (power source).
 */
class ThermalResistor : public SimObject, public ThermalEntity
{
  public:
    typedef ThermalResistorParams Params;
    ThermalResistor(const Params &p);

    void setNodes(ThermalNode * n1, ThermalNode * n2) {
        node1 = n1;
        node2 = n2;
    }

    LinearEquation getEquation(ThermalNode * tn, unsigned n,
                               double step) const override;

  private:
    /* Resistance value in K/W */
    const double _resistance;
    /* Nodes connected to the resistor */
    ThermalNode * node1, * node2;
};

/**
 * A ThermalCapacitor is used to model a thermal capacitance between two
 * thermal domains. This domains can be either a reference (fixed temp.) or
 * a heat producer (power source).
 */
class ThermalCapacitor : public SimObject, public ThermalEntity
{
  public:
    typedef ThermalCapacitorParams Params;
    ThermalCapacitor(const Params &p);

    LinearEquation getEquation(ThermalNode * tn, unsigned n,
                               double step) const override;

    void setNodes(ThermalNode * n1, ThermalNode * n2) {
        node1 = n1;
        node2 = n2;
    }

  private:
    /* Capacitance value in J/K */
    const double _capacitance;
    /* Nodes connected to the resistor */
    ThermalNode * node1, * node2;
};

/**
 * A ThermalReference is a thermal domain with fixed temperature.
 * It's the homologue to the voltage source in a circuit.
 */
class ThermalReference : public SimObject, public ThermalEntity
{
  public:
    typedef ThermalReferenceParams Params;
    ThermalReference(const Params &p);

    void
    setNode(ThermalNode *n)
    {
        node = n;
    }

    LinearEquation getEquation(ThermalNode * tn, unsigned n,
                               double step) const override;

    /* Fixed temperature value */
    const Temperature _temperature;
    /* Nodes connected to the resistor */
    ThermalNode * node;
};


/**
 * @sa \ref gem5PowerModel "gem5 Thermal Model"
 *
 * A ThermalModel is the element which ties all thermal objects
 * together and provides the thermal solver to the system.
 * It is reponsible for updating temperature for all Thermal
 * Domains over time by reading power from simobjects.
 */
class ThermalModel : public ClockedObject
{
  public:
    typedef ThermalModelParams Params;
    ThermalModel(const Params &p);

    void addDomain(ThermalDomain * d);
    void addReference(ThermalReference * r);
    void addCapacitor(ThermalCapacitor * c);
    void addResistor(ThermalResistor * r);

    void addNode(ThermalNode * n) { nodes.push_back(n); }

    Temperature getTemperature() const;

    void startup() override;
    void doStep();

  private:

    /* Keep track of all components used for the thermal model */
    std::vector <ThermalDomain *> domains;
    std::vector <ThermalReference *> references;
    std::vector <ThermalCapacitor *> capacitors;
    std::vector <ThermalResistor *> resistors;

    std::vector <ThermalEntity *> entities;

    /* Keep a list of the instantiated nodes */
    std::vector <ThermalNode*> nodes;
    std::vector <ThermalNode*> eq_nodes;

    /** Stepping event to update the model values */
    EventFunctionWrapper stepEvent;

    /** Step in seconds for thermal updates */
    const double _step;
};

#endif