src/sim/voltage_domain.cc

   1 /*
   2  * Copyright (c) 2012-2014 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
   7  * property including but not limited to intellectual property relating
   8  * to a hardware implementation of the functionality of the software
   9  * licensed hereunder.  You may use the software subject to the license
  10  * terms below provided that you ensure that this notice is replicated
  11  * unmodified and in its entirety in all distributions of the software,
  12  * modified or unmodified, in source code or in binary form.
  13  *
  14  * Redistribution and use in source and binary forms, with or without
  15  * modification, are permitted provided that the following conditions are
  16  * met: redistributions of source code must retain the above copyright
  17  * notice, this list of conditions and the following disclaimer;
  18  * redistributions in binary form must reproduce the above copyright
  19  * notice, this list of conditions and the following disclaimer in the
  20  * documentation and/or other materials provided with the distribution;
  21  * neither the name of the copyright holders nor the names of its
  22  * contributors may be used to endorse or promote products derived from
  23  * this software without specific prior written permission.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  26  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  27  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  28  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  29  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  30  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  31  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  32  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  33  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  34  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  35  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  36  *
  37  * Authors: Vasileios Spiliopoulos
  38  *          Akash Bagdia
  39  */
  40
  41 #include "sim/voltage_domain.hh"
  42
  43 #include <algorithm>
  44
  45 #include "base/statistics.hh"
  46 #include "debug/VoltageDomain.hh"
  47 #include "params/VoltageDomain.hh"
  48 #include "sim/sim_object.hh"
  49
  50 VoltageDomain::VoltageDomain(const Params *p)
  51     : SimObject(p), voltageOpPoints(p->voltage), _perfLevel(0)
  52 {
  53     fatal_if(voltageOpPoints.empty(), "DVFS: Empty set of voltages for "\
  54              "voltage domain %s\n", name());
  55
  56     // Voltages must be sorted in descending order.
  57     fatal_if(!std::is_sorted(voltageOpPoints.begin(), voltageOpPoints.end(),
  58              std::greater<Voltages::value_type>()), "DVFS: Voltage operation "\
  59              "points not in descending order for voltage domain %s\n",
  60              name());
  61 }
  62
  63 void
  64 VoltageDomain::perfLevel(PerfLevel perf_level)
  65 {
  66     chatty_assert(perf_level < voltageOpPoints.size(),
  67                   "DVFS: Requested voltage ID %d is outside the known "\
  68                   "range for domain %s.\n", perf_level, name());
  69
  70     if (perf_level == _perfLevel) {
  71         // Silently ignore identical overwrites
  72         return;
  73     }
  74
  75     _perfLevel = perf_level;
  76
  77     DPRINTF(VoltageDomain, "Setting voltage to %.3fV idx: %d for domain %s\n",
  78             voltage(), perf_level, name());
  79 }
  80
  81 bool
  82 VoltageDomain::sanitiseVoltages()
  83 {
  84     if (numVoltages() == 1)
  85         return false;
  86
  87     // Find the highest requested performance level and update the voltage
  88     // domain with it
  89     PerfLevel perf_max = (PerfLevel)-1;
  90     for (auto dit = srcClockChildren.begin(); dit != srcClockChildren.end(); ++dit) {
  91         SrcClockDomain* d = *dit;
  92         chatty_assert(d->voltageDomain() == this, "DVFS: Clock domain %s "\
  93                       "(id: %d) should not be registered with voltage domain "\
  94                       "%s\n", d->name(), d->domainID(), name());
  95
  96         PerfLevel perf = d->perfLevel();
  97
  98         DPRINTF(VoltageDomain, "DVFS: Clock domain %s (id: %d) requests perf "\
  99                 "level %d\n", d->name(), d->domainID(), perf);
 100
 101         // NOTE: Descending sort of performance levels: 0 - fast, 5 - slow
 102         if (perf < perf_max) {
 103             DPRINTF(VoltageDomain, "DVFS: Updating max perf level %d -> %d\n",
 104                     perf_max, perf);
 105             perf_max = perf;
 106         }
 107     }
 108     DPRINTF(VoltageDomain, "DVFS: Setting perf level of voltage domain %s "\
 109             "from %d to %d.\n", name(), perfLevel(), perf_max);
 110
 111     // Set the performance level
 112     if (perf_max != perfLevel()) {
 113         perfLevel(perf_max);
 114         return true;
 115     } else {
 116         return false;
 117     }
 118 }
 119
 120 void
 121 VoltageDomain::startup() {
 122     bool changed = sanitiseVoltages();
 123     if (changed) {
 124         warn("DVFS: Perf level for voltage domain %s adapted to "\
 125              "requested perf levels from source clock domains.\n", name());
 126     }
 127 }
 128
 129 void
 130 VoltageDomain::regStats()
 131 {
 132     SimObject::regStats();
 133
 134     currentVoltage
 135         .method(this, &VoltageDomain::voltage)
 136         .name(params()->name + ".voltage")
 137         .desc("Voltage in Volts")
 138         ;
 139 }
 140
 141 VoltageDomain *
 142 VoltageDomainParams::create()
 143 {
 144     return new VoltageDomain(this);
 145 }
 146
 147 void
 148 VoltageDomain::serialize(CheckpointOut &cp) const
 149 {
 150     SERIALIZE_SCALAR(_perfLevel);
 151 }
 152
 153 void
 154 VoltageDomain::unserialize(CheckpointIn &cp)
 155 {
 156     UNSERIALIZE_SCALAR(_perfLevel);
 157     perfLevel(_perfLevel);
 158 }