dvfs_handler.cc revision 10395:77b9f96786c1 
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
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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 <set>
43#include <utility>
44
45#include "base/misc.hh"
46#include "debug/DVFS.hh"
47#include "params/DVFSHandler.hh"
48#include "sim/clock_domain.hh"
49#include "sim/dvfs_handler.hh"
50#include "sim/stat_control.hh"
51#include "sim/voltage_domain.hh"
52
53//
54//
55// DVFSHandler methods implementation
56//
57
58DVFSHandler::DVFSHandler(const Params *p)
59    : SimObject(p),
60      sysClkDomain(p->sys_clk_domain),
61      enableHandler(p->enable),
62      _transLatency(p->transition_latency)
63{
64    // Check supplied list of domains for sanity and add them to the
65    // domain ID -> domain* hash
66    for(auto dit = p->domains.begin(); dit != p->domains.end(); ++dit) {
67        SrcClockDomain *d = *dit;
68        DomainID domain_id = d->domainID();
69
70        fatal_if(sysClkDomain == d, "DVFS: Domain config list has a "\
71                 "system clk domain entry");
72        fatal_if(domain_id == SrcClockDomain::emptyDomainID,
73                 "DVFS: Controlled domain %s needs to have a properly "\
74                 " assigned ID.\n", d->name());
75
76        auto entry = std::make_pair(domain_id, d);
77        bool new_elem = domains.insert(entry).second;
78        fatal_if(!new_elem, "DVFS: Domain %s with ID %d does not have a "\
79                 "unique ID.\n", d->name(), domain_id);
80
81        // Create a dedicated event slot per known domain ID
82        UpdateEvent *event = &updatePerfLevelEvents[domain_id];
83        event->domainIDToSet = d->domainID();
84
85        // Add domain ID to the list of domains
86        domainIDList.push_back(d->domainID());
87    }
88    UpdateEvent::dvfsHandler = this;
89}
90
91DVFSHandler *DVFSHandler::UpdateEvent::dvfsHandler;
92
93DVFSHandler::DomainID
94DVFSHandler::domainID(uint32_t index) const
95{
96    fatal_if(index >= numDomains(), "DVFS: Requested index out of "\
97             "bound, max value %d\n", (domainIDList.size() - 1));
98
99    assert(domains.find(domainIDList[index]) != domains.end());
100
101    return domainIDList[index];
102}
103
104bool
105DVFSHandler::validDomainID(DomainID domain_id) const
106{
107    assert(isEnabled());
108    // This is ensure that the domain id as requested by the software is
109    // availabe in the handler.
110    if (domains.find(domain_id) != domains.end())
111        return true;
112    warn("DVFS: invalid domain ID %d, the DVFS handler does not handle this "\
113         "domain\n", domain_id);
114    return false;
115}
116
117bool
118DVFSHandler::perfLevel(DomainID domain_id, PerfLevel perf_level)
119{
120    assert(isEnabled());
121
122    DPRINTF(DVFS, "DVFS: setPerfLevel domain %d -> %d\n", domain_id, perf_level);
123
124    auto d = findDomain(domain_id);
125    if (!d->validPerfLevel(perf_level)) {
126        warn("DVFS: invalid performance level %d for domain ID %d, request "\
127             "ignored\n", perf_level, domain_id);
128        return false;
129    }
130
131    UpdateEvent *update_event = &updatePerfLevelEvents[domain_id];
132    // Drop an old DVFS change request once we have established that this is a
133    // reasonable request
134    if (update_event->scheduled()) {
135        DPRINTF(DVFS, "DVFS: Overwriting the previous DVFS event.\n");
136        deschedule(update_event);
137    }
138
139    update_event->perfLevelToSet = perf_level;
140
141    // State changes that restore to the current state (and / or overwrite a not
142    // yet completed in-flight request) will be squashed
143    if (d->perfLevel() == perf_level) {
144        DPRINTF(DVFS, "DVFS: Ignoring ineffective performance level change "\
145                "%d -> %d\n", d->perfLevel(), perf_level);
146        return false;
147    }
148
149    // At this point, a new transition will certainly take place -> schedule
150    Tick when = curTick() + _transLatency;
151    DPRINTF(DVFS, "DVFS: Update for perf event scheduled for %ld\n", when);
152
153    schedule(update_event, when);
154    return true;
155}
156
157void
158DVFSHandler::UpdateEvent::updatePerfLevel()
159{
160    // Perform explicit stats dump for power estimation before performance
161    // level migration
162    Stats::dump();
163    Stats::reset();
164
165    // Update the performance level in the clock domain
166    auto d = dvfsHandler->findDomain(domainIDToSet);
167    assert(d->perfLevel() != perfLevelToSet);
168
169    d->perfLevel(perfLevelToSet);
170}
171
172void
173DVFSHandler::serialize(std::ostream &os)
174{
175    //This is to ensure that the handler status is maintained during the
176    //entire simulation run and not changed from command line during checkpoint
177    //and restore
178    SERIALIZE_SCALAR(enableHandler);
179
180    // Pull out the hashed data structure into easy-to-serialise arrays;
181    // ensuring that the data associated with any pending update event is saved
182    std::vector<DomainID> domain_ids;
183    std::vector<PerfLevel> perf_levels;
184    std::vector<Tick> whens;
185    for (auto it = updatePerfLevelEvents.begin();
186         it != updatePerfLevelEvents.end(); ++it) {
187        DomainID id = it->first;
188        UpdateEvent *event = &it->second;
189
190        assert(id == event->domainIDToSet);
191        domain_ids.push_back(id);
192        perf_levels.push_back(event->perfLevelToSet);
193        whens.push_back(event->scheduled() ? event->when() : 0);
194    }
195    arrayParamOut(os, "domain_ids", domain_ids);
196    arrayParamOut(os, "perf_levels", perf_levels);
197    arrayParamOut(os, "whens", whens);
198}
199
200void
201DVFSHandler::unserialize(Checkpoint *cp, const std::string &section)
202{
203    bool temp = enableHandler;
204
205    UNSERIALIZE_SCALAR(enableHandler);
206
207    if(temp != enableHandler) {
208        warn("DVFS: Forcing enable handler status to unserialized value of %d",
209             enableHandler);
210    }
211
212    // Reconstruct the map of domain IDs and their scheduled events
213    std::vector<DomainID> domain_ids;
214    std::vector<PerfLevel> perf_levels;
215    std::vector<Tick> whens;
216    arrayParamIn(cp, section, "domain_ids", domain_ids);
217    arrayParamIn(cp, section, "perf_levels", perf_levels);
218    arrayParamIn(cp, section, "whens", whens);
219
220    for (size_t i = 0; i < domain_ids.size(); ++i) {;
221        UpdateEvent *event = &updatePerfLevelEvents[domain_ids[i]];
222
223        event->domainIDToSet = domain_ids[i];
224        event->perfLevelToSet = perf_levels[i];
225
226        // Schedule all previously scheduled events
227        if (whens[i])
228            schedule(event, whens[i]);
229    }
230    UpdateEvent::dvfsHandler = this;
231}
232
233DVFSHandler*
234DVFSHandlerParams::create()
235{
236    return new DVFSHandler(this);
237}
238