1 /* Copyright (c) 2010-2018. 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/s4u/Engine.hpp>
19 #include <xbt/config.hpp>
21 /** @addtogroup SURF_plugin_load
23 This plugin makes it very simple for users to obtain the current load for each host.
27 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(surf_plugin_dvfs, surf, "Logging specific to the SURF HostDvfs plugin");
29 static const char* property_sampling_rate = "plugin/dvfs/sampling_rate";
30 static const char* property_governor = "plugin/dvfs/governor";
39 simgrid::s4u::Host* host;
44 explicit Governor(simgrid::s4u::Host* ptr) : host(ptr) { init(); }
45 virtual ~Governor() = default;
49 const char* local_sampling_rate_config = host->getProperty(property_sampling_rate);
50 double global_sampling_rate_config = xbt_cfg_get_double(property_sampling_rate);
51 if (local_sampling_rate_config != nullptr) {
52 sampling_rate = std::stod(local_sampling_rate_config);
54 sampling_rate = global_sampling_rate_config;
58 virtual void update() = 0;
59 virtual std::string getName() = 0;
60 double samplingRate() { return sampling_rate; }
64 * The linux kernel doc describes this governor as follows:
65 * https://www.kernel.org/doc/Documentation/cpu-freq/governors.txt
67 * > The CPUfreq governor "performance" sets the CPU statically to the
68 * > highest frequency within the borders of scaling_min_freq and
71 * We do not support scaling_min_freq/scaling_max_freq -- we just pick the lowest frequency.
73 class Performance : public Governor {
75 explicit Performance(simgrid::s4u::Host* ptr) : Governor(ptr) {}
77 void update() override { host->setPstate(0); }
78 std::string getName() override { return "Performance"; }
82 * The linux kernel doc describes this governor as follows:
83 * https://www.kernel.org/doc/Documentation/cpu-freq/governors.txt
85 * > The CPUfreq governor "powersave" sets the CPU statically to the
86 * > lowest frequency within the borders of scaling_min_freq and
89 * We do not support scaling_min_freq/scaling_max_freq -- we just pick the lowest frequency.
91 class Powersave : public Governor {
93 explicit Powersave(simgrid::s4u::Host* ptr) : Governor(ptr) {}
95 void update() override { host->setPstate(host->getPstatesCount() - 1); }
96 std::string getName() override { return "Powersave"; }
100 * The linux kernel doc describes this governor as follows:
101 * https://www.kernel.org/doc/Documentation/cpu-freq/governors.txt
103 * > The CPUfreq governor "ondemand" sets the CPU frequency depending on the
104 * > current system load. [...] when triggered, cpufreq checks
105 * > the CPU-usage statistics over the last period and the governor sets the
108 class OnDemand : public Governor {
110 * See https://elixir.bootlin.com/linux/v4.15.4/source/drivers/cpufreq/cpufreq_ondemand.c
111 * DEF_FREQUENCY_UP_THRESHOLD and od_update()
113 double freq_up_threshold = 0.80;
116 explicit OnDemand(simgrid::s4u::Host* ptr) : Governor(ptr) {}
118 std::string getName() override { return "OnDemand"; }
119 void update() override
121 double load = host->getCoreCount() * sg_host_get_avg_load(host);
122 sg_host_load_reset(host); // Only consider the period between two calls to this method!
124 if (load > freq_up_threshold) {
125 host->setPstate(0); /* Run at max. performance! */
126 XBT_INFO("Load: %f > threshold: %f --> changed to pstate %i", load, freq_up_threshold, 0);
128 /* The actual implementation uses a formula here: (See Kernel file cpufreq_ondemand.c:158)
130 * freq_next = min_f + load * (max_f - min_f) / 100
132 * So they assume that frequency increases by 100 MHz. We will just use
133 * lowest_pstate - load*pstatesCount()
135 int max_pstate = host->getPstatesCount() - 1;
136 // Load is now < freq_up_threshold; exclude pstate 0 (the fastest)
137 // because pstate 0 can only be selected if load > freq_up_threshold
138 int new_pstate = max_pstate - load * (max_pstate + 1);
139 host->setPstate(new_pstate);
141 XBT_DEBUG("Load: %f < threshold: %f --> changed to pstate %i", load, freq_up_threshold, new_pstate);
147 * This is the conservative governor, which is very similar to the
148 * OnDemand governor. The Linux Kernel Documentation describes it
149 * very well, see https://www.kernel.org/doc/Documentation/cpu-freq/governors.txt:
151 * > The CPUfreq governor "conservative", much like the "ondemand"
152 * > governor, sets the CPU frequency depending on the current usage. It
153 * > differs in behaviour in that it gracefully increases and decreases the
154 * > CPU speed rather than jumping to max speed the moment there is any load
155 * > on the CPU. This behaviour is more suitable in a battery powered
158 class Conservative : public Governor {
159 double freq_up_threshold = .8;
160 double freq_down_threshold = .2;
163 explicit Conservative(simgrid::s4u::Host* ptr) : Governor(ptr) {}
165 virtual std::string getName() override { return "Conservative"; }
166 virtual void update() override
168 double load = host->getCoreCount() * sg_host_get_avg_load(host);
169 int pstate = host->getPstate();
170 sg_host_load_reset(host); // Only consider the period between two calls to this method!
172 if (load > freq_up_threshold) {
174 host->setPstate(pstate - 1);
175 XBT_INFO("Load: %f > threshold: %f -> increasing performance to pstate %d", load, freq_up_threshold, pstate - 1);
178 XBT_DEBUG("Load: %f > threshold: %f -> but cannot speed up even more, already in highest pstate %d", load, freq_up_threshold, pstate);
180 } else if (load < freq_down_threshold) {
181 int max_pstate = host->getPstatesCount() - 1;
182 if (pstate != max_pstate) { // Are we in the slowest pstate already?
183 host->setPstate(pstate + 1);
184 XBT_INFO("Load: %f < threshold: %f -> slowing down to pstate %d", load, freq_down_threshold, pstate + 1);
187 XBT_DEBUG("Load: %f < threshold: %f -> cannot slow down even more, already in slowest pstate %d", load, freq_down_threshold, pstate);
194 * Add this to your host tag:
195 * - <prop id="plugin/dvfs/governor" value="performance" />
197 * Valid values as of now are: performance, powersave, ondemand, conservative
198 * It doesn't matter if you use uppercase or lowercase.
200 * For the sampling rate, use this:
202 * - <prop id="plugin/dvfs/sampling_rate" value="2" />
204 * This will run the update() method of the specified governor every 2 seconds
207 * These properties can also be used within the <config> tag to configure
208 * these values globally. Using them within the <host> will overwrite this
209 * global configuration
213 static simgrid::xbt::Extension<simgrid::s4u::Host, HostDvfs> EXTENSION_ID;
215 explicit HostDvfs(simgrid::s4u::Host*);
219 simgrid::xbt::Extension<simgrid::s4u::Host, HostDvfs> HostDvfs::EXTENSION_ID;
221 HostDvfs::HostDvfs(simgrid::s4u::Host* ptr) {}
223 HostDvfs::~HostDvfs() = default;
228 using simgrid::plugin::dvfs::HostDvfs;
230 /* **************************** events callback *************************** */
231 static void on_host_added(simgrid::s4u::Host& host)
233 if (dynamic_cast<simgrid::s4u::VirtualMachine*>(&host)) // Ignore virtual machines
236 std::string name = std::string("dvfs-daemon-") + host.get_cname();
237 simgrid::s4u::ActorPtr daemon = simgrid::s4u::Actor::create(name.c_str(), &host, []() {
239 * This lambda function is the function the actor (daemon) will execute
240 * all the time - in the case of the dvfs plugin, this controls when to
241 * lower/raise the frequency.
243 simgrid::s4u::ActorPtr daemon_proc = simgrid::s4u::Actor::self();
245 XBT_DEBUG("DVFS process on %s is a daemon: %d", daemon_proc->get_host()->get_cname(), daemon_proc->is_daemon());
247 std::string dvfs_governor;
248 const char* host_conf = daemon_proc->get_host()->getProperty(property_governor);
249 if (host_conf != nullptr) {
250 dvfs_governor = std::string(daemon_proc->get_host()->getProperty(property_governor));
251 boost::algorithm::to_lower(dvfs_governor);
253 dvfs_governor = xbt_cfg_get_string(property_governor);
254 boost::algorithm::to_lower(dvfs_governor);
257 auto governor = [&dvfs_governor, &daemon_proc]() {
258 if (dvfs_governor == "conservative") {
259 return std::unique_ptr<simgrid::plugin::dvfs::Governor>(
260 new simgrid::plugin::dvfs::Conservative(daemon_proc->get_host()));
261 } else if (dvfs_governor == "ondemand") {
262 return std::unique_ptr<simgrid::plugin::dvfs::Governor>(
263 new simgrid::plugin::dvfs::OnDemand(daemon_proc->get_host()));
264 } else if (dvfs_governor == "performance") {
265 return std::unique_ptr<simgrid::plugin::dvfs::Governor>(
266 new simgrid::plugin::dvfs::Performance(daemon_proc->get_host()));
267 } else if (dvfs_governor == "powersave") {
268 return std::unique_ptr<simgrid::plugin::dvfs::Governor>(
269 new simgrid::plugin::dvfs::Powersave(daemon_proc->get_host()));
271 XBT_CRITICAL("No governor specified for host %s, falling back to Performance",
272 daemon_proc->get_host()->get_cname());
273 return std::unique_ptr<simgrid::plugin::dvfs::Governor>(
274 new simgrid::plugin::dvfs::Performance(daemon_proc->get_host()));
279 // Sleep *before* updating; important for startup (i.e., t = 0).
280 // In the beginning, we want to go with the pstates specified in the platform file
281 // (so we sleep first)
282 simgrid::s4u::this_actor::sleep_for(governor->samplingRate());
284 XBT_DEBUG("Governor (%s) just updated!", governor->getName().c_str());
287 XBT_WARN("I should have never reached this point: daemons should be killed when all regular processes are done");
291 // This call must be placed in this function. Otherweise, the daemonize() call comes too late and
292 // SMPI will take this process as an MPI process!
296 /* **************************** Public interface *************************** */
298 /** \ingroup SURF_plugin_load
299 * \brief Initializes the HostDvfs plugin
300 * \details The HostDvfs plugin provides an API to get the current load of each host.
302 void sg_host_dvfs_plugin_init()
304 if (HostDvfs::EXTENSION_ID.valid())
307 HostDvfs::EXTENSION_ID = simgrid::s4u::Host::extension_create<HostDvfs>();
309 sg_host_load_plugin_init();
311 simgrid::s4u::Host::onCreation.connect(&on_host_added);
312 xbt_cfg_register_double(property_sampling_rate, 0.1, nullptr,
313 "How often should the dvfs plugin check whether the frequency needs to be changed?");
314 xbt_cfg_register_string(property_governor, "performance", nullptr,
315 "Which Governor should be used that adapts the CPU frequency?");