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/load.h"
7 #include "src/include/surf/surf.hpp"
8 #include "src/kernel/activity/ExecImpl.hpp"
9 #include "src/plugins/vm/VirtualMachineImpl.hpp"
10 #include <simgrid/s4u.hpp>
12 SIMGRID_REGISTER_PLUGIN(host_load, "Cpu load", &sg_host_load_plugin_init)
14 /** @addtogroup plugin_load
16 This plugin makes it very simple for users to obtain the current load for each host.
20 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(surf_plugin_load, surf, "Logging specific to the HostLoad plugin");
25 static const double activity_uninitialized_remaining_cost = -1;
29 static simgrid::xbt::Extension<simgrid::s4u::Host, HostLoad> EXTENSION_ID;
31 explicit HostLoad(simgrid::s4u::Host* ptr)
33 , last_updated_(surf_get_clock())
34 , last_reset_(surf_get_clock())
35 , current_speed_(host_->get_speed())
36 , current_flops_(host_->pimpl_cpu->get_constraint()->get_usage())
40 ~HostLoad() = default;
42 explicit HostLoad(simgrid::s4u::Host& ptr) = delete;
43 explicit HostLoad(simgrid::s4u::Host&& ptr) = delete;
45 double get_current_load();
46 /** Get the the average load since last reset(), as a ratio
48 * That's the ratio (amount of flops that were actually computed) / (amount of flops that could have been computed at full speed)
50 double get_average_load() { update(); return (theor_max_flops_ == 0) ? 0 : computed_flops_ / theor_max_flops_; };
51 /** Amount of flops computed since last reset() */
52 double get_computed_flops() { update(); return computed_flops_; }
53 /** Return idle time since last reset() */
54 double get_idle_time() { update(); return idle_time_; }
55 /** Return idle time over the whole simulation */
56 double get_total_idle_time() { update(); return total_idle_time_; }
58 void add_activity(simgrid::kernel::activity::ExecImplPtr activity);
62 simgrid::s4u::Host* host_ = nullptr;
63 /* Stores all currently ongoing activities (computations) on this machine */
64 std::map<simgrid::kernel::activity::ExecImplPtr, /* cost still remaining*/double> current_activities;
65 double last_updated_ = 0;
66 double last_reset_ = 0;
68 * current_speed each core is running at; we need to store this as the speed
69 * will already have changed once we get notified
71 double current_speed_ = 0;
73 * How many flops are currently used by all the processes running on this
76 double current_flops_ = 0;
77 double computed_flops_ = 0;
78 double idle_time_ = 0;
79 double total_idle_time_ = 0; /* This gets never reset */
80 double theor_max_flops_ = 0;
83 simgrid::xbt::Extension<simgrid::s4u::Host, HostLoad> HostLoad::EXTENSION_ID;
85 void HostLoad::add_activity(simgrid::kernel::activity::ExecImplPtr activity)
87 current_activities.insert({activity, activity_uninitialized_remaining_cost});
90 void HostLoad::update()
92 double now = surf_get_clock();
94 // This loop updates the flops that the host executed for the ongoing computations
95 auto iter = begin(current_activities);
96 while (iter != end(current_activities)) {
97 auto& activity = iter->first; // Just an alias
98 auto& remaining_cost_after_last_update = iter->second; // Just an alias
99 auto current_iter = iter;
102 if (activity->surf_action_->get_finish_time() != now && activity->state_ == e_smx_state_t::SIMIX_RUNNING) {
103 if (remaining_cost_after_last_update == activity_uninitialized_remaining_cost) {
104 remaining_cost_after_last_update = activity->surf_action_->get_cost();
106 double computed_flops_since_last_update = remaining_cost_after_last_update - /*remaining now*/activity->get_remaining();
107 computed_flops_ += computed_flops_since_last_update;
108 remaining_cost_after_last_update = activity->get_remaining();
110 else if (activity->state_ == e_smx_state_t::SIMIX_DONE) {
111 computed_flops_ += remaining_cost_after_last_update;
112 current_activities.erase(current_iter);
116 /* Current flop per second computed by the cpu; current_flops = k * pstate_speed_in_flops, k @in {0, 1, ..., cores-1}
117 * designates number of active cores; will be 0 if CPU is currently idle */
118 current_flops_ = host_->pimpl_cpu->get_constraint()->get_usage();
120 if (current_flops_ == 0) {
121 idle_time_ += (now - last_updated_);
122 total_idle_time_ += (now - last_updated_);
123 XBT_DEBUG("[%s]: Currently idle -> Added %f seconds to idle time (totaling %fs)", host_->get_cname(), (now - last_updated_), idle_time_);
126 theor_max_flops_ += current_speed_ * host_->get_core_count() * (now - last_updated_);
127 current_speed_ = host_->get_speed();
131 /** @brief Get the current load as a ratio = achieved_flops / (core_current_speed * core_amount)
133 * You may also want to check simgrid::s4u::Host::get_load() that simply returns
134 * the achieved flop rate (in flops per seconds), ie the load that a new action arriving on
135 * that host would suffer.
137 * Please note that this function only returns an instantaneous load that may be deceiving
138 * in some scenarios. For example, imagine that an activity terminates at time t, and that
139 * another activity is created on the same host at the exact same timestamp. The load was
140 * never 0 on the simulated machine since the time did not advance between the two events.
141 * But still, if you call this function between the two events (in the simulator course), it
142 * returns 0 although there is no time (in the simulated time) where this value is valid.
144 double HostLoad::get_current_load()
146 // We don't need to call update() here because it is called every time an action terminates or starts
147 return current_flops_ / static_cast<double>(host_->get_speed() * host_->get_core_count());
151 * Resets the counters
153 void HostLoad::reset()
155 last_updated_ = surf_get_clock();
156 last_reset_ = surf_get_clock();
159 theor_max_flops_ = 0;
160 current_flops_ = host_->pimpl_cpu->get_constraint()->get_usage();
161 current_speed_ = host_->get_speed();
163 } // namespace plugin
164 } // namespace simgrid
166 using simgrid::plugin::HostLoad;
168 /* **************************** events callback *************************** */
169 /* This callback is fired either when the host changes its state (on/off) or its speed
170 * (because the user changed the pstate, or because of external trace events) */
171 static void on_host_change(simgrid::s4u::Host& host)
173 if (dynamic_cast<simgrid::s4u::VirtualMachine*>(&host)) // Ignore virtual machines
176 host.extension<HostLoad>()->update();
179 /* This callback is called when an action (computation, idle, ...) terminates */
180 static void on_action_state_change(simgrid::surf::CpuAction* action, simgrid::kernel::resource::Action::State /*previous*/)
182 for (simgrid::surf::Cpu* const& cpu : action->cpus()) {
183 simgrid::s4u::Host* host = cpu->get_host();
185 if (dynamic_cast<simgrid::s4u::VirtualMachine*>(host)) // Ignore virtual machines
188 if (host != nullptr) {
189 host->extension<HostLoad>()->update();
194 /* **************************** Public interface *************************** */
196 /** @brief Initializes the HostLoad plugin
197 * @details The HostLoad plugin provides an API to get the current load of each host.
199 void sg_host_load_plugin_init()
201 if (HostLoad::EXTENSION_ID.valid())
204 HostLoad::EXTENSION_ID = simgrid::s4u::Host::extension_create<HostLoad>();
206 if (simgrid::s4u::Engine::is_initialized()) { // If not yet initialized, this would create a new instance
207 // which would cause seg faults...
208 simgrid::s4u::Engine* e = simgrid::s4u::Engine::get_instance();
209 for (auto& host : e->get_all_hosts()) {
210 host->extension_set(new HostLoad(host));
214 /* When attaching a callback into a signal, you can use a lambda as follows, or a regular function as done below */
216 simgrid::s4u::Host::on_creation.connect([](simgrid::s4u::Host& host) {
217 if (dynamic_cast<simgrid::s4u::VirtualMachine*>(&host)) // Ignore virtual machines
219 host.extension_set(new HostLoad(&host));
222 simgrid::kernel::activity::ExecImpl::on_creation.connect([](simgrid::kernel::activity::ExecImplPtr activity){
223 if (activity->host_ != nullptr) { // We only run on one host
224 simgrid::s4u::Host* host = activity->host_;
225 if (dynamic_cast<simgrid::s4u::VirtualMachine*>(activity->host_))
226 host = dynamic_cast<simgrid::s4u::VirtualMachine*>(activity->host_)->get_pm();
228 host->extension<HostLoad>()->add_activity(activity);
229 host->extension<HostLoad>()->update(); // If the system was idle until now, we need to update *before*
230 // this computation starts running so we can keep track of the
231 // idle time. (Communication operations don't trigger this hook!)
233 else { // This runs on multiple hosts
234 XBT_DEBUG("HostLoad plugin currently does not support executions on several hosts");
237 simgrid::kernel::activity::ExecImpl::on_completion.connect([](simgrid::kernel::activity::ExecImplPtr activity){
238 if (activity->host_ != nullptr) { // We only run on one host
239 simgrid::s4u::Host* host = activity->host_;
240 if (dynamic_cast<simgrid::s4u::VirtualMachine*>(activity->host_))
241 host = dynamic_cast<simgrid::s4u::VirtualMachine*>(activity->host_)->get_pm();
243 host->extension<HostLoad>()->update();
245 else { // This runs on multiple hosts
246 XBT_DEBUG("HostLoad plugin currently does not support executions on several hosts");
249 simgrid::s4u::Host::on_state_change.connect(&on_host_change);
250 simgrid::s4u::Host::on_speed_change.connect(&on_host_change);
253 /** @brief Returns the current load of that host, as a ratio = achieved_flops / (core_current_speed * core_amount)
255 * See simgrid::plugin::HostLoad::get_current_load() for the full documentation.
257 double sg_host_get_current_load(sg_host_t host)
259 xbt_assert(HostLoad::EXTENSION_ID.valid(),
260 "The Load plugin is not active. Please call sg_host_load_plugin_init() during initialization.");
262 return host->extension<HostLoad>()->get_current_load();
265 /** @brief Returns the current load of the host passed as argument
267 * See also @ref plugin_load
269 double sg_host_get_avg_load(sg_host_t host)
271 xbt_assert(HostLoad::EXTENSION_ID.valid(),
272 "The Load plugin is not active. Please call sg_host_load_plugin_init() during initialization.");
274 return host->extension<HostLoad>()->get_average_load();
277 /** @brief Returns the time this host was idle since the last reset
279 * See also @ref plugin_load
281 double sg_host_get_idle_time(sg_host_t host)
283 xbt_assert(HostLoad::EXTENSION_ID.valid(),
284 "The Load plugin is not active. Please call sg_host_load_plugin_init() during initialization.");
286 return host->extension<HostLoad>()->get_idle_time();
289 double sg_host_get_total_idle_time(sg_host_t host)
291 xbt_assert(HostLoad::EXTENSION_ID.valid(),
292 "The Load plugin is not active. Please call sg_host_load_plugin_init() during initialization.");
294 return host->extension<HostLoad>()->get_total_idle_time();
297 double sg_host_get_computed_flops(sg_host_t host)
299 xbt_assert(HostLoad::EXTENSION_ID.valid(),
300 "The Load plugin is not active. Please call sg_host_load_plugin_init() during initialization.");
302 return host->extension<HostLoad>()->get_computed_flops();
305 void sg_host_load_reset(sg_host_t host)
307 xbt_assert(HostLoad::EXTENSION_ID.valid(),
308 "The Load plugin is not active. Please call sg_host_load_plugin_init() during initialization.");
310 host->extension<HostLoad>()->reset();