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 = sg_host_get_current_load(host);
124 // FIXME I don't like that we multiply with the getCoreCount() just here...
125 if (load*host->getCoreCount() > freq_up_threshold) {
126 host->setPstate(0); /* Run at max. performance! */
127 XBT_INFO("Load: %f > threshold: %f --> changed to pstate %i", load * host->getCoreCount(), 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 int new_pstate = max_pstate - load * max_pstate;
138 host->setPstate(new_pstate);
140 XBT_DEBUG("Load: %f --> changed to pstate %i", load*host->getCoreCount(), new_pstate);
146 * This is the conservative governor, which is very similar to the
147 * OnDemand governor. The Linux Kernel Documentation describes it
148 * very well, see https://www.kernel.org/doc/Documentation/cpu-freq/governors.txt:
150 * > The CPUfreq governor "conservative", much like the "ondemand"
151 * > governor, sets the CPU frequency depending on the current usage. It
152 * > differs in behaviour in that it gracefully increases and decreases the
153 * > CPU speed rather than jumping to max speed the moment there is any load
154 * > on the CPU. This behaviour is more suitable in a battery powered
157 class Conservative : public Governor {
158 double freq_up_threshold = .8;
159 double freq_down_threshold = .2;
162 explicit Conservative(simgrid::s4u::Host* ptr) : Governor(ptr) {}
164 virtual std::string getName() override { return "Conservative"; }
165 virtual void update() override
167 double load = sg_host_get_current_load(host)*host->getCoreCount();
168 int pstate = host->getPstate();
170 if (load > freq_up_threshold) {
172 host->setPstate(pstate - 1);
173 XBT_INFO("Load: %f > threshold: %f -> increasing performance to pstate %d", load, freq_up_threshold, pstate - 1);
176 XBT_DEBUG("Load: %f > threshold: %f -> but cannot speed up even more, already in highest pstate %d", load, freq_up_threshold, pstate);
178 } else if (load < freq_down_threshold) {
179 int max_pstate = host->getPstatesCount() - 1;
180 if (pstate != max_pstate) { // Are we in the slowest pstate already?
181 host->setPstate(pstate + 1);
182 XBT_INFO("Load: %f < threshold: %f -> slowing down to pstate %d", load, freq_down_threshold, pstate + 1);
185 XBT_DEBUG("Load: %f < threshold: %f -> cannot slow down even more, already in slowest pstate %d", load, freq_down_threshold, pstate);
192 * Add this to your host tag:
193 * - <prop id="plugin/dvfs/governor" value="performance" />
195 * Valid values as of now are: performance, powersave, ondemand, conservative
196 * It doesn't matter if you use uppercase or lowercase.
198 * For the sampling rate, use this:
200 * - <prop id="plugin/dvfs/sampling_rate" value="2" />
202 * This will run the update() method of the specified governor every 2 seconds
205 * These properties can also be used within the <config> tag to configure
206 * these values globally. Using them within the <host> will overwrite this
207 * global configuration
211 static simgrid::xbt::Extension<simgrid::s4u::Host, HostDvfs> EXTENSION_ID;
213 explicit HostDvfs(simgrid::s4u::Host*);
217 simgrid::xbt::Extension<simgrid::s4u::Host, HostDvfs> HostDvfs::EXTENSION_ID;
219 HostDvfs::HostDvfs(simgrid::s4u::Host* ptr) {}
221 HostDvfs::~HostDvfs() = default;
226 using simgrid::plugin::dvfs::HostDvfs;
228 /* **************************** events callback *************************** */
229 static void on_host_added(simgrid::s4u::Host& host)
231 if (dynamic_cast<simgrid::s4u::VirtualMachine*>(&host)) // Ignore virtual machines
234 std::string name = std::string("dvfs-daemon-") + host.getCname();
235 simgrid::s4u::ActorPtr daemon = simgrid::s4u::Actor::createActor(name.c_str(), &host, []() {
237 * This lambda function is the function the actor (daemon) will execute
238 * all the time - in the case of the dvfs plugin, this controls when to
239 * lower/raise the frequency.
241 simgrid::s4u::ActorPtr daemonProc = simgrid::s4u::Actor::self();
243 XBT_DEBUG("DVFS process on %s is a daemon: %d", daemonProc->getHost()->getName().c_str(), daemonProc->isDaemon());
245 std::string dvfs_governor;
246 const char* host_conf = daemonProc->getHost()->getProperty(property_governor);
247 if (host_conf != nullptr) {
248 dvfs_governor = std::string(daemonProc->getHost()->getProperty(property_governor));
249 boost::algorithm::to_lower(dvfs_governor);
251 dvfs_governor = xbt_cfg_get_string(property_governor);
252 boost::algorithm::to_lower(dvfs_governor);
255 auto governor = [&dvfs_governor, &daemonProc]() {
256 if (dvfs_governor == "conservative") {
257 return std::unique_ptr<simgrid::plugin::dvfs::Governor>(
258 new simgrid::plugin::dvfs::Conservative(daemonProc->getHost()));
259 } else if (dvfs_governor == "ondemand") {
260 return std::unique_ptr<simgrid::plugin::dvfs::Governor>(
261 new simgrid::plugin::dvfs::OnDemand(daemonProc->getHost()));
262 } else if (dvfs_governor == "performance") {
263 return std::unique_ptr<simgrid::plugin::dvfs::Governor>(
264 new simgrid::plugin::dvfs::Performance(daemonProc->getHost()));
265 } else if (dvfs_governor == "powersave") {
266 return std::unique_ptr<simgrid::plugin::dvfs::Governor>(
267 new simgrid::plugin::dvfs::Powersave(daemonProc->getHost()));
269 XBT_CRITICAL("No governor specified for host %s, falling back to Performance",
270 daemonProc->getHost()->getCname());
271 return std::unique_ptr<simgrid::plugin::dvfs::Governor>(
272 new simgrid::plugin::dvfs::Performance(daemonProc->getHost()));
277 // Sleep *before* updating; important for startup (i.e., t = 0).
278 // In the beginning, we want to go with the pstates specified in the platform file
279 // (so we sleep first)
280 simgrid::s4u::this_actor::sleep_for(governor->samplingRate());
282 XBT_DEBUG("Governor (%s) just updated!", governor->getName().c_str());
285 XBT_WARN("I should have never reached this point: daemons should be killed when all regular processes are done");
289 // This call must be placed in this function. Otherweise, the daemonize() call comes too late and
290 // SMPI will take this process as an MPI process!
294 /* **************************** Public interface *************************** */
297 /** \ingroup SURF_plugin_load
298 * \brief Initializes the HostDvfs plugin
299 * \details The HostDvfs plugin provides an API to get the current load of each host.
301 void sg_host_dvfs_plugin_init()
303 if (HostDvfs::EXTENSION_ID.valid())
306 HostDvfs::EXTENSION_ID = simgrid::s4u::Host::extension_create<HostDvfs>();
308 sg_host_load_plugin_init();
310 simgrid::s4u::Host::onCreation.connect(&on_host_added);
311 xbt_cfg_register_double(property_sampling_rate, 0.1, nullptr,
312 "How often should the dvfs plugin check whether the frequency needs to be changed?");
313 xbt_cfg_register_string(property_governor, "performance", nullptr,
314 "Which Governor should be used that adapts the CPU frequency?");