clocked_object.cc revision 11524 
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
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: Akash Bagdia
38 *          David Guillen Fandos
39 */
40
41#include "sim/clocked_object.hh"
42
43#include "base/misc.hh"
44
45void
46ClockedObject::serialize(CheckpointOut &cp) const
47{
48    unsigned int currPwrState = (unsigned int)_currPwrState;
49
50    SERIALIZE_SCALAR(currPwrState);
51    SERIALIZE_SCALAR(prvEvalTick);
52}
53
54void
55ClockedObject::unserialize(CheckpointIn &cp)
56{
57    unsigned int currPwrState;
58
59    UNSERIALIZE_SCALAR(currPwrState);
60    UNSERIALIZE_SCALAR(prvEvalTick);
61
62    _currPwrState = Enums::PwrState(currPwrState);
63}
64
65void
66ClockedObject::pwrState(Enums::PwrState p)
67{
68    // Function should ideally be called only when there is a state change
69    if (_currPwrState == p) {
70        warn("ClockedObject: Already in the requested power state, request "\
71             "ignored");
72        return;
73    }
74
75    // No need to compute stats if in the same tick, update state though. This
76    // can happen in cases like a) during start of the simulation multiple
77    // state changes happens in init/startup phase, b) one takes a decision to
78    // migrate state but decides to reverts back to the original state in the
79    // same tick if other conditions are not met elsewhere.
80    // Any state change related stats would have been recorded on previous call
81    // to the pwrState() function.
82    if (prvEvalTick == curTick()) {
83        warn("ClockedObject: More than one power state change request "\
84             "encountered within the same simulation tick");
85        _currPwrState = p;
86        return;
87    }
88
89    // Record stats for previous state.
90    computeStats();
91
92    _currPwrState = p;
93
94    numPwrStateTransitions++;
95}
96
97void
98ClockedObject::computeStats()
99{
100    // Calculate time elapsed from last (valid) state change
101    Tick elapsed_time = curTick() - prvEvalTick;
102
103    pwrStateResidencyTicks[_currPwrState] += elapsed_time;
104
105    // Time spent in CLK_GATED state, this might change depending on
106    // transition to other low power states in respective simulation
107    // objects.
108    if (_currPwrState == Enums::PwrState::CLK_GATED) {
109        pwrStateClkGateDist.sample(elapsed_time);
110    }
111
112    prvEvalTick = curTick();
113}
114
115std::vector<double>
116ClockedObject::pwrStateWeights() const
117{
118    // Get residency stats
119    std::vector<double> ret;
120    Stats::VCounter residencies;
121    pwrStateResidencyTicks.value(residencies);
122
123    // Account for current state too!
124    Tick elapsed_time = curTick() - prvEvalTick;
125    residencies[_currPwrState] += elapsed_time;
126
127    ret.resize(Enums::PwrState::Num_PwrState);
128    for (unsigned i = 0; i < Enums::PwrState::Num_PwrState; i++)
129        ret[i] = residencies[i] / \
130                     (pwrStateResidencyTicks.total() + elapsed_time);
131
132    return ret;
133}
134
135void
136ClockedObject::regStats()
137{
138    SimObject::regStats();
139
140    using namespace Stats;
141
142    numPwrStateTransitions
143        .name(params()->name + ".numPwrStateTransitions")
144        .desc("Number of power state transitions")
145        ;
146
147    // Each sample is time in ticks
148    unsigned num_bins = std::max(params()->p_state_clk_gate_bins, 10U);
149    pwrStateClkGateDist
150        .init(params()->p_state_clk_gate_min, params()->p_state_clk_gate_max,
151          (params()->p_state_clk_gate_max / num_bins))
152        .name(params()->name + ".pwrStateClkGateDist")
153        .desc("Distribution of time spent in the clock gated state")
154        .flags(pdf)
155        ;
156
157    pwrStateResidencyTicks
158        .init(Enums::PwrState::Num_PwrState)
159        .name(params()->name + ".pwrStateResidencyTicks")
160        .desc("Cumulative time (in ticks) in various power states")
161        ;
162    for (int i = 0; i < Enums::PwrState::Num_PwrState; i++) {
163        pwrStateResidencyTicks.subname(i, Enums::PwrStateStrings[i]);
164    }
165
166    numPwrStateTransitions = 0;
167
168    /**
169     * For every stats dump, the power state residency and other distribution
170     * stats should be computed just before the dump to ensure correct stats
171     * value being reported for current dump window. It avoids things like
172     * having any unreported time spent in a power state to be forwarded to the
173     * next dump window which might have rather unpleasant effects (like
174     * perturbing the distribution stats).
175     */
176    registerDumpCallback(new ClockedObjectDumpCallback(this));
177}
178