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,
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 *          Stephan Diestelhorst
40 */
41
42#include "sim/dvfs_handler.hh"
43
44#include <set>
45#include <utility>
46
47#include "base/logging.hh"
48#include "base/trace.hh"
49#include "debug/DVFS.hh"
50#include "params/DVFSHandler.hh"
51#include "sim/clock_domain.hh"
52#include "sim/eventq_impl.hh"
53#include "sim/stat_control.hh"
54#include "sim/voltage_domain.hh"
55
56//
57//
58// DVFSHandler methods implementation
59//
60
61DVFSHandler::DVFSHandler(const Params *p)
62    : SimObject(p),
63      sysClkDomain(p->sys_clk_domain),
64      enableHandler(p->enable),
65      _transLatency(p->transition_latency)
66{
67    // Check supplied list of domains for sanity and add them to the
68    // domain ID -> domain* hash
69    for (auto dit = p->domains.begin(); dit != p->domains.end(); ++dit) {
70        SrcClockDomain *d = *dit;
71        DomainID domain_id = d->domainID();
72
73        fatal_if(sysClkDomain == d, "DVFS: Domain config list has a "\
74                 "system clk domain entry");
75        fatal_if(domain_id == SrcClockDomain::emptyDomainID,
76                 "DVFS: Controlled domain %s needs to have a properly "\
77                 " assigned ID.\n", d->name());
78
79        auto entry = std::make_pair(domain_id, d);
80        bool new_elem = domains.insert(entry).second;
81        fatal_if(!new_elem, "DVFS: Domain %s with ID %d does not have a "\
82                 "unique ID.\n", d->name(), domain_id);
83
84        // Create a dedicated event slot per known domain ID
85        UpdateEvent *event = &updatePerfLevelEvents[domain_id];
86        event->domainIDToSet = d->domainID();
87
88        // Add domain ID to the list of domains
89        domainIDList.push_back(d->domainID());
90    }
91    UpdateEvent::dvfsHandler = this;
92}
93
94DVFSHandler *DVFSHandler::UpdateEvent::dvfsHandler;
95
96DVFSHandler::DomainID
97DVFSHandler::domainID(uint32_t index) const
98{
99    fatal_if(index >= numDomains(), "DVFS: Requested index out of "\
100             "bound, max value %d\n", (domainIDList.size() - 1));
101
102    assert(domains.find(domainIDList[index]) != domains.end());
103
104    return domainIDList[index];
105}
106
107bool
108DVFSHandler::validDomainID(DomainID domain_id) const
109{
110    assert(isEnabled());
111    // This is ensure that the domain id as requested by the software is
112    // availabe in the handler.
113    if (domains.find(domain_id) != domains.end())
114        return true;
115    warn("DVFS: invalid domain ID %d, the DVFS handler does not handle this "\
116         "domain\n", domain_id);
117    return false;
118}
119
120bool
121DVFSHandler::perfLevel(DomainID domain_id, PerfLevel perf_level)
122{
123    assert(isEnabled());
124
125    DPRINTF(DVFS, "DVFS: setPerfLevel domain %d -> %d\n", domain_id, perf_level);
126
127    auto d = findDomain(domain_id);
128    if (!d->validPerfLevel(perf_level)) {
129        warn("DVFS: invalid performance level %d for domain ID %d, request "\
130             "ignored\n", perf_level, domain_id);
131        return false;
132    }
133
134    UpdateEvent *update_event = &updatePerfLevelEvents[domain_id];
135    // Drop an old DVFS change request once we have established that this is a
136    // reasonable request
137    if (update_event->scheduled()) {
138        DPRINTF(DVFS, "DVFS: Overwriting the previous DVFS event.\n");
139        deschedule(update_event);
140    }
141
142    update_event->perfLevelToSet = perf_level;
143
144    // State changes that restore to the current state (and / or overwrite a not
145    // yet completed in-flight request) will be squashed
146    if (d->perfLevel() == perf_level) {
147        DPRINTF(DVFS, "DVFS: Ignoring ineffective performance level change "\
148                "%d -> %d\n", d->perfLevel(), perf_level);
149        return false;
150    }
151
152    // At this point, a new transition will certainly take place -> schedule
153    Tick when = curTick() + _transLatency;
154    DPRINTF(DVFS, "DVFS: Update for perf event scheduled for %ld\n", when);
155
156    schedule(update_event, when);
157    return true;
158}
159
160void
161DVFSHandler::UpdateEvent::updatePerfLevel()
162{
163    // Perform explicit stats dump for power estimation before performance
164    // level migration
165    Stats::dump();
166    Stats::reset();
167
168    // Update the performance level in the clock domain
169    auto d = dvfsHandler->findDomain(domainIDToSet);
170    assert(d->perfLevel() != perfLevelToSet);
171
172    d->perfLevel(perfLevelToSet);
173}
174
175double
176DVFSHandler::voltageAtPerfLevel(DomainID domain_id, PerfLevel perf_level) const
177{
178    VoltageDomain *d = findDomain(domain_id)->voltageDomain();
179    assert(d);
180    PerfLevel n = d->numVoltages();
181    if (perf_level < n)
182        return d->voltage(perf_level);
183
184    // Request outside of the range of the voltage domain
185    if (n == 1) {
186        DPRINTF(DVFS, "DVFS: Request for perf-level %i for single-point "\
187                "voltage domain %s.  Returning voltage at level 0: %.2f "\
188                "V\n", perf_level, d->name(), d->voltage(0));
189        // Special case for single point voltage domain -> same voltage for
190        // all points
191        return d->voltage(0);
192    }
193
194    warn("DVFSHandler %s reads illegal voltage level %u from "\
195         "VoltageDomain %s. Returning 0 V\n", name(), perf_level, d->name());
196    return 0.;
197}
198
199void
200DVFSHandler::serialize(CheckpointOut &cp) const
201{
202    //This is to ensure that the handler status is maintained during the
203    //entire simulation run and not changed from command line during checkpoint
204    //and restore
205    SERIALIZE_SCALAR(enableHandler);
206
207    // Pull out the hashed data structure into easy-to-serialise arrays;
208    // ensuring that the data associated with any pending update event is saved
209    std::vector<DomainID> domain_ids;
210    std::vector<PerfLevel> perf_levels;
211    std::vector<Tick> whens;
212    for (const auto &ev_pair : updatePerfLevelEvents) {
213        DomainID id = ev_pair.first;
214        const UpdateEvent *event = &ev_pair.second;
215
216        assert(id == event->domainIDToSet);
217        domain_ids.push_back(id);
218        perf_levels.push_back(event->perfLevelToSet);
219        whens.push_back(event->scheduled() ? event->when() : 0);
220    }
221    SERIALIZE_CONTAINER(domain_ids);
222    SERIALIZE_CONTAINER(perf_levels);
223    SERIALIZE_CONTAINER(whens);
224}
225
226void
227DVFSHandler::unserialize(CheckpointIn &cp)
228{
229    bool temp = enableHandler;
230
231    UNSERIALIZE_SCALAR(enableHandler);
232
233    if (temp != enableHandler) {
234        warn("DVFS: Forcing enable handler status to unserialized value of %d",
235             enableHandler);
236    }
237
238    // Reconstruct the map of domain IDs and their scheduled events
239    std::vector<DomainID> domain_ids;
240    std::vector<PerfLevel> perf_levels;
241    std::vector<Tick> whens;
242    UNSERIALIZE_CONTAINER(domain_ids);
243    UNSERIALIZE_CONTAINER(perf_levels);
244    UNSERIALIZE_CONTAINER(whens);
245
246    for (size_t i = 0; i < domain_ids.size(); ++i) {;
247        UpdateEvent *event = &updatePerfLevelEvents[domain_ids[i]];
248
249        event->domainIDToSet = domain_ids[i];
250        event->perfLevelToSet = perf_levels[i];
251
252        // Schedule all previously scheduled events
253        if (whens[i])
254            schedule(event, whens[i]);
255    }
256    UpdateEvent::dvfsHandler = this;
257}
258
259DVFSHandler*
260DVFSHandlerParams::create()
261{
262    return new DVFSHandler(this);
263}
264