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 "base/trace.hh"
  47 #include "debug/VoltageDomain.hh"
  48 #include "params/VoltageDomain.hh"
  49 #include "sim/sim_object.hh"
  50
  51 VoltageDomain::VoltageDomain(const Params *p)
  52     : SimObject(p), voltageOpPoints(p->voltage), _perfLevel(0)
  53 {
  54     fatal_if(voltageOpPoints.empty(), "DVFS: Empty set of voltages for "\
  55              "voltage domain %s\n", name());
  56
  57     // Voltages must be sorted in descending order.
  58     fatal_if(!std::is_sorted(voltageOpPoints.begin(), voltageOpPoints.end(),
  59              std::greater<Voltages::value_type>()), "DVFS: Voltage operation "\
  60              "points not in descending order for voltage domain %s\n",
  61              name());
  62 }
  63
  64 void
  65 VoltageDomain::perfLevel(PerfLevel perf_level)
  66 {
  67     chatty_assert(perf_level < voltageOpPoints.size(),
  68                   "DVFS: Requested voltage ID %d is outside the known "\
  69                   "range for domain %s.\n", perf_level, name());
  70
  71     if (perf_level == _perfLevel) {
  72         // Silently ignore identical overwrites
  73         return;
  74     }
  75
  76     _perfLevel = perf_level;
  77
  78     DPRINTF(VoltageDomain, "Setting voltage to %.3fV idx: %d for domain %s\n",
  79             voltage(), perf_level, name());
  80 }
  81
  82 bool
  83 VoltageDomain::sanitiseVoltages()
  84 {
  85     if (numVoltages() == 1)
  86         return false;
  87
  88     // Find the highest requested performance level and update the voltage
  89     // domain with it
  90     PerfLevel perf_max = (PerfLevel)-1;
  91     for (auto dit = srcClockChildren.begin(); dit != srcClockChildren.end(); ++dit) {
  92         SrcClockDomain* d = *dit;
  93         chatty_assert(d->voltageDomain() == this, "DVFS: Clock domain %s "\
  94                       "(id: %d) should not be registered with voltage domain "\
  95                       "%s\n", d->name(), d->domainID(), name());
  96
  97         PerfLevel perf = d->perfLevel();
  98
  99         DPRINTF(VoltageDomain, "DVFS: Clock domain %s (id: %d) requests perf "\
 100                 "level %d\n", d->name(), d->domainID(), perf);
 101
 102         // NOTE: Descending sort of performance levels: 0 - fast, 5 - slow
 103         if (perf < perf_max) {
 104             DPRINTF(VoltageDomain, "DVFS: Updating max perf level %d -> %d\n",
 105                     perf_max, perf);
 106             perf_max = perf;
 107         }
 108     }
 109     DPRINTF(VoltageDomain, "DVFS: Setting perf level of voltage domain %s "\
 110             "from %d to %d.\n", name(), perfLevel(), perf_max);
 111
 112     // Set the performance level
 113     if (perf_max != perfLevel()) {
 114         perfLevel(perf_max);
 115         return true;
 116     } else {
 117         return false;
 118     }
 119 }
 120
 121 void
 122 VoltageDomain::startup() {
 123     bool changed = sanitiseVoltages();
 124     if (changed) {
 125         warn("DVFS: Perf level for voltage domain %s adapted to "\
 126              "requested perf levels from source clock domains.\n", name());
 127     }
 128 }
 129
 130 void
 131 VoltageDomain::regStats()
 132 {
 133     SimObject::regStats();
 134
 135     currentVoltage
 136         .method(this, &VoltageDomain::voltage)
 137         .name(params()->name + ".voltage")
 138         .desc("Voltage in Volts")
 139         ;
 140 }
 141
 142 VoltageDomain *
 143 VoltageDomainParams::create()
 144 {
 145     return new VoltageDomain(this);
 146 }
 147
 148 void
 149 VoltageDomain::serialize(CheckpointOut &cp) const
 150 {
 151     SERIALIZE_SCALAR(_perfLevel);
 152 }
 153
 154 void
 155 VoltageDomain::unserialize(CheckpointIn &cp)
 156 {
 157     UNSERIALIZE_SCALAR(_perfLevel);
 158     perfLevel(_perfLevel);
 159 }