1 /* Copyright (c) 2010, 2012-2018. The SimGrid Team. All rights reserved. */
3 /* This program is free software; you can redistribute it and/or modify it
4 * under the terms of the license (GNU LGPL) which comes with this package. */
6 #include "simgrid/plugins/dvfs.h"
7 #include "simgrid/plugins/load.h"
8 #include "simgrid/simix.hpp"
9 #include "src/plugins/vm/VirtualMachineImpl.hpp"
10 #include "src/surf/cpu_interface.hpp"
12 #include <boost/algorithm/string.hpp>
13 #include <boost/algorithm/string/classification.hpp>
14 #include <boost/algorithm/string/split.hpp>
15 #include <simgrid/msg.h>
16 #include <simgrid/s4u/Engine.hpp>
20 #include <xbt/config.hpp>
22 /** @addtogroup SURF_plugin_load
24 This plugin makes it very simple for users to obtain the current load for each host.
28 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(surf_plugin_dvfs, surf, "Logging specific to the SURF HostDvfs plugin");
30 static const char* property_sampling_rate = "plugin/dvfs/sampling_rate";
31 static const char* property_governor = "plugin/dvfs/governor";
40 simgrid::s4u::Host* host;
45 explicit Governor(simgrid::s4u::Host* ptr) : host(ptr) { init(); }
46 virtual ~Governor() = default;
50 const char* local_sampling_rate_config = host->getProperty(property_sampling_rate);
51 double global_sampling_rate_config = xbt_cfg_get_double(property_sampling_rate);
52 if (local_sampling_rate_config != nullptr) {
53 sampling_rate = std::stod(local_sampling_rate_config);
55 sampling_rate = global_sampling_rate_config;
59 virtual void update() = 0;
60 virtual std::string getName() = 0;
61 double samplingRate() { return sampling_rate; }
65 * The linux kernel doc describes this governor as follows:
66 * https://www.kernel.org/doc/Documentation/cpu-freq/governors.txt
68 * > The CPUfreq governor "performance" sets the CPU statically to the
69 * > highest frequency within the borders of scaling_min_freq and
72 * We do not support scaling_min_freq/scaling_max_freq -- we just pick the lowest frequency.
74 class Performance : public Governor {
76 explicit Performance(simgrid::s4u::Host* ptr) : Governor(ptr) {}
78 void update() override { host->setPstate(0); }
79 std::string getName() override { return "Performance"; }
83 * The linux kernel doc describes this governor as follows:
84 * https://www.kernel.org/doc/Documentation/cpu-freq/governors.txt
86 * > The CPUfreq governor "powersave" sets the CPU statically to the
87 * > lowest frequency within the borders of scaling_min_freq and
90 * We do not support scaling_min_freq/scaling_max_freq -- we just pick the lowest frequency.
92 class Powersave : public Governor {
94 explicit Powersave(simgrid::s4u::Host* ptr) : Governor(ptr) {}
96 void update() override { host->setPstate(host->getPstatesCount() - 1); }
97 std::string getName() override { return "Powersave"; }
101 * The linux kernel doc describes this governor as follows:
102 * https://www.kernel.org/doc/Documentation/cpu-freq/governors.txt
104 * > The CPUfreq governor "ondemand" sets the CPU frequency depending on the
105 * > current system load. [...] when triggered, cpufreq checks
106 * > the CPU-usage statistics over the last period and the governor sets the
109 class OnDemand : public Governor {
111 * See https://elixir.bootlin.com/linux/v4.15.4/source/drivers/cpufreq/cpufreq_ondemand.c
112 * DEF_FREQUENCY_UP_THRESHOLD and od_update()
114 double freq_up_threshold = 0.80;
117 explicit OnDemand(simgrid::s4u::Host* ptr) : Governor(ptr) {}
119 std::string getName() override { return "OnDemand"; }
120 void update() override
122 double load = host->getCoreCount() * sg_host_get_avg_load(host);
123 sg_host_load_reset(host); // Only consider the period between two calls to this method!
125 if (load > freq_up_threshold) {
126 host->setPstate(0); /* Run at max. performance! */
127 XBT_INFO("Load: %f > threshold: %f --> changed to pstate %i", load, freq_up_threshold, 0);
129 /* The actual implementation uses a formula here: (See Kernel file cpufreq_ondemand.c:158)
131 * freq_next = min_f + load * (max_f - min_f) / 100
133 * So they assume that frequency increases by 100 MHz. We will just use
134 * lowest_pstate - load*pstatesCount()
136 int max_pstate = host->getPstatesCount() - 1;
137 // Load is now < freq_up_threshold; exclude pstate 0 (the fastest)
138 // because pstate 0 can only be selected if load > freq_up_threshold
139 int new_pstate = max_pstate - load * (max_pstate + 1);
140 host->setPstate(new_pstate);
142 XBT_DEBUG("Load: %f < threshold: %f --> changed to pstate %i", load, freq_up_threshold, new_pstate);
148 * This is the conservative governor, which is very similar to the
149 * OnDemand governor. The Linux Kernel Documentation describes it
150 * very well, see https://www.kernel.org/doc/Documentation/cpu-freq/governors.txt:
152 * > The CPUfreq governor "conservative", much like the "ondemand"
153 * > governor, sets the CPU frequency depending on the current usage. It
154 * > differs in behaviour in that it gracefully increases and decreases the
155 * > CPU speed rather than jumping to max speed the moment there is any load
156 * > on the CPU. This behaviour is more suitable in a battery powered
159 class Conservative : public Governor {
160 double freq_up_threshold = .8;
161 double freq_down_threshold = .2;
164 explicit Conservative(simgrid::s4u::Host* ptr) : Governor(ptr) {}
166 virtual std::string getName() override { return "Conservative"; }
167 virtual void update() override
169 double load = host->getCoreCount() * sg_host_get_avg_load(host);
170 int pstate = host->getPstate();
171 sg_host_load_reset(host); // Only consider the period between two calls to this method!
173 if (load > freq_up_threshold) {
175 host->setPstate(pstate - 1);
176 XBT_INFO("Load: %f > threshold: %f -> increasing performance to pstate %d", load, freq_up_threshold, pstate - 1);
179 XBT_DEBUG("Load: %f > threshold: %f -> but cannot speed up even more, already in highest pstate %d", load, freq_up_threshold, pstate);
181 } else if (load < freq_down_threshold) {
182 int max_pstate = host->getPstatesCount() - 1;
183 if (pstate != max_pstate) { // Are we in the slowest pstate already?
184 host->setPstate(pstate + 1);
185 XBT_INFO("Load: %f < threshold: %f -> slowing down to pstate %d", load, freq_down_threshold, pstate + 1);
188 XBT_DEBUG("Load: %f < threshold: %f -> cannot slow down even more, already in slowest pstate %d", load, freq_down_threshold, pstate);
195 * Add this to your host tag:
196 * - <prop id="plugin/dvfs/governor" value="performance" />
198 * Valid values as of now are: performance, powersave, ondemand, conservative
199 * It doesn't matter if you use uppercase or lowercase.
201 * For the sampling rate, use this:
203 * - <prop id="plugin/dvfs/sampling_rate" value="2" />
205 * This will run the update() method of the specified governor every 2 seconds
208 * These properties can also be used within the <config> tag to configure
209 * these values globally. Using them within the <host> will overwrite this
210 * global configuration
214 static simgrid::xbt::Extension<simgrid::s4u::Host, HostDvfs> EXTENSION_ID;
216 explicit HostDvfs(simgrid::s4u::Host*);
220 simgrid::xbt::Extension<simgrid::s4u::Host, HostDvfs> HostDvfs::EXTENSION_ID;
222 HostDvfs::HostDvfs(simgrid::s4u::Host* ptr) {}
224 HostDvfs::~HostDvfs() = default;
229 using simgrid::plugin::dvfs::HostDvfs;
231 /* **************************** events callback *************************** */
232 static void on_host_added(simgrid::s4u::Host& host)
234 if (dynamic_cast<simgrid::s4u::VirtualMachine*>(&host)) // Ignore virtual machines
237 std::string name = std::string("dvfs-daemon-") + host.getCname();
238 simgrid::s4u::ActorPtr daemon = simgrid::s4u::Actor::createActor(name.c_str(), &host, []() {
240 * This lambda function is the function the actor (daemon) will execute
241 * all the time - in the case of the dvfs plugin, this controls when to
242 * lower/raise the frequency.
244 simgrid::s4u::ActorPtr daemonProc = simgrid::s4u::Actor::self();
246 XBT_DEBUG("DVFS process on %s is a daemon: %d", daemonProc->getHost()->getName().c_str(), daemonProc->isDaemon());
248 std::string dvfs_governor;
249 const char* host_conf = daemonProc->getHost()->getProperty(property_governor);
250 if (host_conf != nullptr) {
251 dvfs_governor = std::string(daemonProc->getHost()->getProperty(property_governor));
252 boost::algorithm::to_lower(dvfs_governor);
254 dvfs_governor = xbt_cfg_get_string(property_governor);
255 boost::algorithm::to_lower(dvfs_governor);
258 auto governor = [&dvfs_governor, &daemonProc]() {
259 if (dvfs_governor == "conservative") {
260 return std::unique_ptr<simgrid::plugin::dvfs::Governor>(
261 new simgrid::plugin::dvfs::Conservative(daemonProc->getHost()));
262 } else if (dvfs_governor == "ondemand") {
263 return std::unique_ptr<simgrid::plugin::dvfs::Governor>(
264 new simgrid::plugin::dvfs::OnDemand(daemonProc->getHost()));
265 } else if (dvfs_governor == "performance") {
266 return std::unique_ptr<simgrid::plugin::dvfs::Governor>(
267 new simgrid::plugin::dvfs::Performance(daemonProc->getHost()));
268 } else if (dvfs_governor == "powersave") {
269 return std::unique_ptr<simgrid::plugin::dvfs::Governor>(
270 new simgrid::plugin::dvfs::Powersave(daemonProc->getHost()));
272 XBT_CRITICAL("No governor specified for host %s, falling back to Performance",
273 daemonProc->getHost()->getCname());
274 return std::unique_ptr<simgrid::plugin::dvfs::Governor>(
275 new simgrid::plugin::dvfs::Performance(daemonProc->getHost()));
280 // Sleep *before* updating; important for startup (i.e., t = 0).
281 // In the beginning, we want to go with the pstates specified in the platform file
282 // (so we sleep first)
283 simgrid::s4u::this_actor::sleep_for(governor->samplingRate());
285 XBT_DEBUG("Governor (%s) just updated!", governor->getName().c_str());
288 XBT_WARN("I should have never reached this point: daemons should be killed when all regular processes are done");
292 // This call must be placed in this function. Otherweise, the daemonize() call comes too late and
293 // SMPI will take this process as an MPI process!
297 /* **************************** Public interface *************************** */
300 /** \ingroup SURF_plugin_load
301 * \brief Initializes the HostDvfs plugin
302 * \details The HostDvfs plugin provides an API to get the current load of each host.
304 void sg_host_dvfs_plugin_init()
306 if (HostDvfs::EXTENSION_ID.valid())
309 HostDvfs::EXTENSION_ID = simgrid::s4u::Host::extension_create<HostDvfs>();
311 sg_host_load_plugin_init();
313 simgrid::s4u::Host::onCreation.connect(&on_host_added);
314 xbt_cfg_register_double(property_sampling_rate, 0.1, nullptr,
315 "How often should the dvfs plugin check whether the frequency needs to be changed?");
316 xbt_cfg_register_string(property_governor, "performance", nullptr,
317 "Which Governor should be used that adapts the CPU frequency?");