src/sim/clocked_object.cc

   1 /*
   2  * Copyright (c) 2015-2016 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
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  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: Akash Bagdia
  38  *          David Guillen Fandos
  39  */
  40
  41 #include "sim/clocked_object.hh"
  42
  43 #include "base/logging.hh"
  44 #include "sim/power/power_model.hh"
  45
  46 ClockedObject::ClockedObject(const ClockedObjectParams *p) :
  47     SimObject(p), Clocked(*p->clk_domain),
  48     _currPwrState(p->default_p_state),
  49     prvEvalTick(0),
  50     stats(*this)
  51 {
  52     // Register the power_model with the object
  53     for (auto & power_model: p->power_model)
  54         power_model->setClockedObject(this);
  55 }
  56
  57 void
  58 ClockedObject::serialize(CheckpointOut &cp) const
  59 {
  60     unsigned int currPwrState = (unsigned int)_currPwrState;
  61
  62     SERIALIZE_SCALAR(currPwrState);
  63     SERIALIZE_SCALAR(prvEvalTick);
  64 }
  65
  66 void
  67 ClockedObject::unserialize(CheckpointIn &cp)
  68 {
  69     unsigned int currPwrState;
  70
  71     UNSERIALIZE_SCALAR(currPwrState);
  72     UNSERIALIZE_SCALAR(prvEvalTick);
  73
  74     _currPwrState = Enums::PwrState(currPwrState);
  75 }
  76
  77 void
  78 ClockedObject::pwrState(Enums::PwrState p)
  79 {
  80     // Function should ideally be called only when there is a state change
  81     if (_currPwrState == p) {
  82         warn_once("ClockedObject: Already in the requested power state, " \
  83                   "request ignored");
  84         return;
  85     }
  86
  87     // No need to compute stats if in the same tick, update state though. This
  88     // can happen in cases like a) during start of the simulation multiple
  89     // state changes happens in init/startup phase, b) one takes a decision to
  90     // migrate state but decides to reverts back to the original state in the
  91     // same tick if other conditions are not met elsewhere.
  92     // Any state change related stats would have been recorded on previous call
  93     // to the pwrState() function.
  94     if (prvEvalTick == curTick() && curTick() != 0) {
  95        warn("ClockedObject %s: More than one power state change request "\
  96              "encountered within the same simulation tick %d",
  97              name(), prvEvalTick);
  98         _currPwrState = p;
  99         return;
 100     }
 101
 102     // Record stats for previous state.
 103     computeStats();
 104
 105     _currPwrState = p;
 106
 107     stats.numPwrStateTransitions++;
 108 }
 109
 110 void
 111 ClockedObject::computeStats()
 112 {
 113     // Calculate time elapsed from last (valid) state change
 114     Tick elapsed_time = curTick() - prvEvalTick;
 115
 116     stats.pwrStateResidencyTicks[_currPwrState] += elapsed_time;
 117
 118     // Time spent in CLK_GATED state, this might change depending on
 119     // transition to other low power states in respective simulation
 120     // objects.
 121     if (_currPwrState == Enums::PwrState::CLK_GATED) {
 122         stats.pwrStateClkGateDist.sample(elapsed_time);
 123     }
 124
 125     prvEvalTick = curTick();
 126 }
 127
 128 std::vector<double>
 129 ClockedObject::pwrStateWeights() const
 130 {
 131     // Get residency stats
 132     std::vector<double> ret;
 133     Stats::VCounter residencies;
 134     stats.pwrStateResidencyTicks.value(residencies);
 135
 136     // Account for current state too!
 137     Tick elapsed_time = curTick() - prvEvalTick;
 138     residencies[_currPwrState] += elapsed_time;
 139
 140     ret.resize(Enums::PwrState::Num_PwrState);
 141     for (unsigned i = 0; i < Enums::PwrState::Num_PwrState; i++)
 142         ret[i] = residencies[i] / \
 143                      (stats.pwrStateResidencyTicks.total() + elapsed_time);
 144
 145     return ret;
 146 }
 147
 148
 149 ClockedObject::ClockedObjectStats::ClockedObjectStats(ClockedObject &co)
 150     : Stats::Group(&co),
 151     clockedObject(co),
 152     ADD_STAT(numPwrStateTransitions,
 153              "Number of power state transitions"),
 154     ADD_STAT(pwrStateClkGateDist,
 155              "Distribution of time spent in the clock gated state"),
 156     ADD_STAT(pwrStateResidencyTicks,
 157              "Cumulative time (in ticks) in various power states")
 158 {
 159 }
 160
 161 void
 162 ClockedObject::ClockedObjectStats::regStats()
 163 {
 164     Stats::Group::regStats();
 165
 166     using namespace Stats;
 167
 168     const ClockedObjectParams *p = clockedObject.params();
 169
 170     numPwrStateTransitions.flags(nozero);
 171
 172     // Each sample is time in ticks
 173     unsigned num_bins = std::max(p->p_state_clk_gate_bins, 10U);
 174     pwrStateClkGateDist
 175         .init(p->p_state_clk_gate_min, p->p_state_clk_gate_max,
 176           (p->p_state_clk_gate_max / num_bins))
 177         .flags(pdf | nozero | nonan)
 178         ;
 179
 180     pwrStateResidencyTicks
 181         .init(Enums::PwrState::Num_PwrState)
 182         .flags(nozero)
 183         ;
 184     for (int i = 0; i < Enums::PwrState::Num_PwrState; i++) {
 185         pwrStateResidencyTicks.subname(i, Enums::PwrStateStrings[i]);
 186     }
 187
 188     numPwrStateTransitions = 0;
 189 }
 190
 191 void
 192 ClockedObject::ClockedObjectStats::preDumpStats()
 193 {
 194     Stats::Group::preDumpStats();
 195
 196     /**
 197      * For every stats dump, the power state residency and other distribution
 198      * stats should be computed just before the dump to ensure correct stats
 199      * value being reported for current dump window. It avoids things like
 200      * having any unreported time spent in a power state to be forwarded to the
 201      * next dump window which might have rather unpleasant effects (like
 202      * perturbing the distribution stats).
 203      */
 204     clockedObject.computeStats();
 205 }