src/sim/voltage_domain.hh

   1 /*
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   3  * All rights reserved
   4  *
   5  * The license below extends only to copyright in the software and shall
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  37
  38 #ifndef __SIM_VOLTAGE_DOMAIN_HH__
  39 #define __SIM_VOLTAGE_DOMAIN_HH__
  40
  41 #include <vector>
  42
  43 #include "base/statistics.hh"
  44 #include "params/VoltageDomain.hh"
  45 #include "sim/clock_domain.hh"
  46 #include "sim/sim_object.hh"
  47
  48 /**
  49  * A VoltageDomain is used to group clock domains that operate under
  50  * the same voltage. The class provides methods for setting and
  51  * getting the voltage.
  52  */
  53 class VoltageDomain : public SimObject
  54 {
  55   public:
  56
  57     typedef VoltageDomainParams Params;
  58     VoltageDomain(const Params &p);
  59
  60     typedef SrcClockDomain::PerfLevel PerfLevel;
  61
  62     /**
  63      * Get the current voltage.
  64      *
  65      * @return Voltage of the domain
  66      */
  67     double voltage() const { return voltageOpPoints[_perfLevel]; }
  68
  69     /**
  70      * Get the voltage at specified performance level.
  71      *
  72      * @param perf_level Performance level for which the voltage is requested
  73      * @return Voltage of the domain at specified performance level
  74      */
  75     double voltage(PerfLevel perf_level) const
  76     {
  77         chatty_assert(perf_level < numVoltages(), "VoltageDomain %s "\
  78                       "request for voltage perf level %u is outside "\
  79                       "of numVoltages %u", name(), perf_level,
  80                       numVoltages());
  81         return voltageOpPoints[perf_level];
  82     }
  83
  84     uint32_t numVoltages() const { return (uint32_t)voltageOpPoints.size(); }
  85
  86     /**
  87      * Set the voltage point of the domain.
  88      * @param Voltage value to be set
  89      */
  90     void perfLevel(PerfLevel perf_level);
  91
  92     /**
  93      * Get the voltage point of the domain.
  94      * @param Voltage value to be set
  95      */
  96     PerfLevel perfLevel() const { return _perfLevel; }
  97
  98     /**
  99      * Register a SrcClockDomain with this voltage domain.
 100      * @param src_clock_domain The SrcClockDomain to register.
 101      */
 102     void registerSrcClockDom(SrcClockDomain *src_clock_dom) {
 103         assert(src_clock_dom->voltageDomain() == this);
 104         srcClockChildren.push_back(src_clock_dom);
 105     }
 106
 107     /**
 108      * Startup has all SrcClockDomains registered with this voltage domain, so
 109      * try to make sure that all perf level requests from them are met.
 110      */
 111     void startup() override;
 112
 113     /**
 114      * Recomputes the highest (fastest, i.e., numerically lowest) requested
 115      * performance level of all associated clock domains, and updates the
 116      * performance level of this voltage domain to match.  This means that for
 117      * two connected clock domains, one fast and one slow, the voltage domain
 118      * will provide the voltage associated with the fast DVFS operation point.
 119      * Must be called whenever a clock domain decides to swtich its performance
 120      * level.
 121      *
 122      * @return True, if the voltage was actually changed.
 123      */
 124     bool sanitiseVoltages();
 125
 126     void serialize(CheckpointOut &cp) const override;
 127     void unserialize(CheckpointIn &cp) override;
 128
 129   private:
 130     typedef std::vector<double> Voltages;
 131     /**
 132      * List of possible minimum voltage at each of the frequency operational
 133      * points, should be in descending order and same size as freqOpPoints.
 134      * An empty list corresponds to default voltage specified for the voltage
 135      * domain its clock domain belongs. The same voltage is applied for each
 136      * freqOpPoints, overall implying NO DVS
 137      */
 138     const Voltages voltageOpPoints;
 139     PerfLevel _perfLevel;
 140
 141     struct VoltageDomainStats : public Stats::Group
 142     {
 143         VoltageDomainStats(VoltageDomain &vd);
 144
 145         /**
 146          * Stat for reporting voltage of the domain
 147          */
 148         Stats::Value voltage;
 149     } stats;
 150
 151     /**
 152      * List of associated SrcClockDomains that are connected to this voltage
 153      * domain.
 154      */
 155     typedef std::vector<SrcClockDomain *> SrcClockChildren;
 156     SrcClockChildren srcClockChildren;
 157 };
 158
 159 #endif