src/sim/voltage_domain.cc

   1 /*
   2  * Copyright (c) 2012-2014, 2019 ARM Limited
   3  * All rights reserved
   4  *
   5  * The license below extends only to copyright in the software and shall
   6  * not be construed as granting a license to any other intellectual
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   8  * to a hardware implementation of the functionality of the software
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  12  * modified or unmodified, in source code or in binary form.
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  14  * Redistribution and use in source and binary forms, with or without
  15  * modification, are permitted provided that the following conditions are
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  23  * this software without specific prior written permission.
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  26  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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  35  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  36  */
  37
  38 #include "sim/voltage_domain.hh"
  39
  40 #include <algorithm>
  41
  42 #include "base/logging.hh"
  43 #include "base/trace.hh"
  44 #include "debug/VoltageDomain.hh"
  45 #include "params/VoltageDomain.hh"
  46 #include "sim/serialize.hh"
  47
  48 VoltageDomain::VoltageDomain(const Params &p)
  49     : SimObject(p), voltageOpPoints(p.voltage), _perfLevel(0), stats(*this)
  50 {
  51     fatal_if(voltageOpPoints.empty(), "DVFS: Empty set of voltages for "\
  52              "voltage domain %s\n", name());
  53
  54     // Voltages must be sorted in descending order.
  55     fatal_if(!std::is_sorted(voltageOpPoints.begin(), voltageOpPoints.end(),
  56              std::greater<Voltages::value_type>()), "DVFS: Voltage operation "\
  57              "points not in descending order for voltage domain %s\n",
  58              name());
  59 }
  60
  61 void
  62 VoltageDomain::perfLevel(PerfLevel perf_level)
  63 {
  64     chatty_assert(perf_level < voltageOpPoints.size(),
  65                   "DVFS: Requested voltage ID %d is outside the known "\
  66                   "range for domain %s.\n", perf_level, name());
  67
  68     if (perf_level == _perfLevel) {
  69         // Silently ignore identical overwrites
  70         return;
  71     }
  72
  73     _perfLevel = perf_level;
  74
  75     DPRINTF(VoltageDomain, "Setting voltage to %.3fV idx: %d for domain %s\n",
  76             voltage(), perf_level, name());
  77 }
  78
  79 bool
  80 VoltageDomain::sanitiseVoltages()
  81 {
  82     if (numVoltages() == 1)
  83         return false;
  84
  85     // Find the highest requested performance level and update the voltage
  86     // domain with it
  87     PerfLevel perf_max = (PerfLevel)-1;
  88     for (auto dit = srcClockChildren.begin(); dit != srcClockChildren.end(); ++dit) {
  89         SrcClockDomain* d = *dit;
  90         chatty_assert(d->voltageDomain() == this, "DVFS: Clock domain %s "\
  91                       "(id: %d) should not be registered with voltage domain "\
  92                       "%s\n", d->name(), d->domainID(), name());
  93
  94         PerfLevel perf = d->perfLevel();
  95
  96         DPRINTF(VoltageDomain, "DVFS: Clock domain %s (id: %d) requests perf "\
  97                 "level %d\n", d->name(), d->domainID(), perf);
  98
  99         // NOTE: Descending sort of performance levels: 0 - fast, 5 - slow
 100         if (perf < perf_max) {
 101             DPRINTF(VoltageDomain, "DVFS: Updating max perf level %d -> %d\n",
 102                     perf_max, perf);
 103             perf_max = perf;
 104         }
 105     }
 106     DPRINTF(VoltageDomain, "DVFS: Setting perf level of voltage domain %s "\
 107             "from %d to %d.\n", name(), perfLevel(), perf_max);
 108
 109     // Set the performance level
 110     if (perf_max != perfLevel()) {
 111         perfLevel(perf_max);
 112         return true;
 113     } else {
 114         return false;
 115     }
 116 }
 117
 118 void
 119 VoltageDomain::startup() {
 120     bool changed = sanitiseVoltages();
 121     if (changed) {
 122         warn("DVFS: Perf level for voltage domain %s adapted to "\
 123              "requested perf levels from source clock domains.\n", name());
 124     }
 125 }
 126
 127 void
 128 VoltageDomain::serialize(CheckpointOut &cp) const
 129 {
 130     SERIALIZE_SCALAR(_perfLevel);
 131 }
 132
 133 void
 134 VoltageDomain::unserialize(CheckpointIn &cp)
 135 {
 136     UNSERIALIZE_SCALAR(_perfLevel);
 137     perfLevel(_perfLevel);
 138 }
 139
 140 VoltageDomain::VoltageDomainStats::VoltageDomainStats(VoltageDomain &vd)
 141     : Stats::Group(&vd),
 142     ADD_STAT(voltage, UNIT_VOLT, "Voltage in Volts")
 143 {
 144     voltage.method(&vd, &VoltageDomain::voltage);
 145 }