src/sim/dvfs_handler.cc

   1 /*
   2  * Copyright (c) 2013-2014 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,
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  35  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  36  */
  37
  38 #include "sim/dvfs_handler.hh"
  39
  40 #include <set>
  41 #include <utility>
  42
  43 #include "base/logging.hh"
  44 #include "base/trace.hh"
  45 #include "debug/DVFS.hh"
  46 #include "params/DVFSHandler.hh"
  47 #include "sim/clock_domain.hh"
  48 #include "sim/eventq.hh"
  49 #include "sim/stat_control.hh"
  50 #include "sim/voltage_domain.hh"
  51
  52 //
  53 //
  54 // DVFSHandler methods implementation
  55 //
  56
  57 DVFSHandler::DVFSHandler(const Params *p)
  58     : SimObject(p),
  59       sysClkDomain(p->sys_clk_domain),
  60       enableHandler(p->enable),
  61       _transLatency(p->transition_latency)
  62 {
  63     // Check supplied list of domains for sanity and add them to the
  64     // domain ID -> domain* hash
  65     for (auto dit = p->domains.begin(); dit != p->domains.end(); ++dit) {
  66         SrcClockDomain *d = *dit;
  67         DomainID domain_id = d->domainID();
  68
  69         fatal_if(sysClkDomain == d, "DVFS: Domain config list has a "\
  70                  "system clk domain entry");
  71         fatal_if(domain_id == SrcClockDomain::emptyDomainID,
  72                  "DVFS: Controlled domain %s needs to have a properly "\
  73                  " assigned ID.\n", d->name());
  74
  75         auto entry = std::make_pair(domain_id, d);
  76         bool new_elem = domains.insert(entry).second;
  77         fatal_if(!new_elem, "DVFS: Domain %s with ID %d does not have a "\
  78                  "unique ID.\n", d->name(), domain_id);
  79
  80         // Create a dedicated event slot per known domain ID
  81         UpdateEvent *event = &updatePerfLevelEvents[domain_id];
  82         event->domainIDToSet = d->domainID();
  83
  84         // Add domain ID to the list of domains
  85         domainIDList.push_back(d->domainID());
  86     }
  87     UpdateEvent::dvfsHandler = this;
  88 }
  89
  90 DVFSHandler *DVFSHandler::UpdateEvent::dvfsHandler;
  91
  92 DVFSHandler::DomainID
  93 DVFSHandler::domainID(uint32_t index) const
  94 {
  95     fatal_if(index >= numDomains(), "DVFS: Requested index out of "\
  96              "bound, max value %d\n", (domainIDList.size() - 1));
  97
  98     assert(domains.find(domainIDList[index]) != domains.end());
  99
 100     return domainIDList[index];
 101 }
 102
 103 bool
 104 DVFSHandler::validDomainID(DomainID domain_id) const
 105 {
 106     assert(isEnabled());
 107     // This is ensure that the domain id as requested by the software is
 108     // availabe in the handler.
 109     if (domains.find(domain_id) != domains.end())
 110         return true;
 111     warn("DVFS: invalid domain ID %d, the DVFS handler does not handle this "\
 112          "domain\n", domain_id);
 113     return false;
 114 }
 115
 116 bool
 117 DVFSHandler::perfLevel(DomainID domain_id, PerfLevel perf_level)
 118 {
 119     assert(isEnabled());
 120
 121     DPRINTF(DVFS, "DVFS: setPerfLevel domain %d -> %d\n", domain_id, perf_level);
 122
 123     auto d = findDomain(domain_id);
 124     if (!d->validPerfLevel(perf_level)) {
 125         warn("DVFS: invalid performance level %d for domain ID %d, request "\
 126              "ignored\n", perf_level, domain_id);
 127         return false;
 128     }
 129
 130     UpdateEvent *update_event = &updatePerfLevelEvents[domain_id];
 131     // Drop an old DVFS change request once we have established that this is a
 132     // reasonable request
 133     if (update_event->scheduled()) {
 134         DPRINTF(DVFS, "DVFS: Overwriting the previous DVFS event.\n");
 135         deschedule(update_event);
 136     }
 137
 138     update_event->perfLevelToSet = perf_level;
 139
 140     // State changes that restore to the current state (and / or overwrite a not
 141     // yet completed in-flight request) will be squashed
 142     if (d->perfLevel() == perf_level) {
 143         DPRINTF(DVFS, "DVFS: Ignoring ineffective performance level change "\
 144                 "%d -> %d\n", d->perfLevel(), perf_level);
 145         return false;
 146     }
 147
 148     // At this point, a new transition will certainly take place -> schedule
 149     Tick when = curTick() + _transLatency;
 150     DPRINTF(DVFS, "DVFS: Update for perf event scheduled for %ld\n", when);
 151
 152     schedule(update_event, when);
 153     return true;
 154 }
 155
 156 void
 157 DVFSHandler::UpdateEvent::updatePerfLevel()
 158 {
 159     // Perform explicit stats dump for power estimation before performance
 160     // level migration
 161     Stats::dump();
 162     Stats::reset();
 163
 164     // Update the performance level in the clock domain
 165     auto d = dvfsHandler->findDomain(domainIDToSet);
 166     assert(d->perfLevel() != perfLevelToSet);
 167
 168     d->perfLevel(perfLevelToSet);
 169 }
 170
 171 double
 172 DVFSHandler::voltageAtPerfLevel(DomainID domain_id, PerfLevel perf_level) const
 173 {
 174     VoltageDomain *d = findDomain(domain_id)->voltageDomain();
 175     assert(d);
 176     PerfLevel n = d->numVoltages();
 177     if (perf_level < n)
 178         return d->voltage(perf_level);
 179
 180     // Request outside of the range of the voltage domain
 181     if (n == 1) {
 182         DPRINTF(DVFS, "DVFS: Request for perf-level %i for single-point "\
 183                 "voltage domain %s.  Returning voltage at level 0: %.2f "\
 184                 "V\n", perf_level, d->name(), d->voltage(0));
 185         // Special case for single point voltage domain -> same voltage for
 186         // all points
 187         return d->voltage(0);
 188     }
 189
 190     warn("DVFSHandler %s reads illegal voltage level %u from "\
 191          "VoltageDomain %s. Returning 0 V\n", name(), perf_level, d->name());
 192     return 0.;
 193 }
 194
 195 void
 196 DVFSHandler::serialize(CheckpointOut &cp) const
 197 {
 198     //This is to ensure that the handler status is maintained during the
 199     //entire simulation run and not changed from command line during checkpoint
 200     //and restore
 201     SERIALIZE_SCALAR(enableHandler);
 202
 203     // Pull out the hashed data structure into easy-to-serialise arrays;
 204     // ensuring that the data associated with any pending update event is saved
 205     std::vector<DomainID> domain_ids;
 206     std::vector<PerfLevel> perf_levels;
 207     std::vector<Tick> whens;
 208     for (const auto &ev_pair : updatePerfLevelEvents) {
 209         DomainID id = ev_pair.first;
 210         const UpdateEvent *event = &ev_pair.second;
 211
 212         assert(id == event->domainIDToSet);
 213         domain_ids.push_back(id);
 214         perf_levels.push_back(event->perfLevelToSet);
 215         whens.push_back(event->scheduled() ? event->when() : 0);
 216     }
 217     SERIALIZE_CONTAINER(domain_ids);
 218     SERIALIZE_CONTAINER(perf_levels);
 219     SERIALIZE_CONTAINER(whens);
 220 }
 221
 222 void
 223 DVFSHandler::unserialize(CheckpointIn &cp)
 224 {
 225     bool temp = enableHandler;
 226
 227     UNSERIALIZE_SCALAR(enableHandler);
 228
 229     if (temp != enableHandler) {
 230         warn("DVFS: Forcing enable handler status to unserialized value of %d",
 231              enableHandler);
 232     }
 233
 234     // Reconstruct the map of domain IDs and their scheduled events
 235     std::vector<DomainID> domain_ids;
 236     std::vector<PerfLevel> perf_levels;
 237     std::vector<Tick> whens;
 238     UNSERIALIZE_CONTAINER(domain_ids);
 239     UNSERIALIZE_CONTAINER(perf_levels);
 240     UNSERIALIZE_CONTAINER(whens);
 241
 242     for (size_t i = 0; i < domain_ids.size(); ++i) {;
 243         UpdateEvent *event = &updatePerfLevelEvents[domain_ids[i]];
 244
 245         event->domainIDToSet = domain_ids[i];
 246         event->perfLevelToSet = perf_levels[i];
 247
 248         // Schedule all previously scheduled events
 249         if (whens[i])
 250             schedule(event, whens[i]);
 251     }
 252     UpdateEvent::dvfsHandler = this;
 253 }
 254
 255 DVFSHandler*
 256 DVFSHandlerParams::create()
 257 {
 258     return new DVFSHandler(this);
 259 }