-/* Copyright (c) 2017-2018. The SimGrid Team. All rights reserved. */
+/* Copyright (c) 2017-2019. The SimGrid Team. All rights reserved. */
/* This program is free software; you can redistribute it and/or modify it
* under the terms of the license (GNU LGPL) which comes with this package. */
-#include "xbt/log.h"
#include <simgrid/s4u.hpp>
+/* This example shows how to use simgrid::s4u::Engine::get_filtered_hosts() to retrieve
+ * all hosts that match a given criteria. This criteria can be specified either with:
+ * - an inlined callback
+ * - a boolean function, such as filter_speed_more_than_50Mf() below
+ * - a functor (= function object), that can either be stateless such as filter::SingleCore below, or that can save
+ * state such as filter::FrequencyChanged below
+ *
+ * This file provides examples for each of these categories. You should implement your own filters in your code.
+ */
+
XBT_LOG_NEW_DEFAULT_CATEGORY(s4u_engine_filtering, "Messages specific for this s4u example");
namespace filter {
+/* First example of thing that we can use as a filtering criteria: a simple boolean function */
+static bool filter_speed_more_than_50Mf(const simgrid::s4u::Host* host)
+{
+ return host->get_speed() > 50E6;
+}
+
+/* Second kind of thing that we can use as a filtering criteria: a functor (=function object).
+ * This one is a bit stupid: it's a lot of boilerplate over a dummy boolean function.
+ */
+class SingleCore {
+public:
+ bool operator()(const simgrid::s4u::Host* host) { return host->get_core_count() == 1; }
+};
+
+/* This functor is a bit more complex, as it saves the current state when created.
+ * Then, it allows one to easily retrieve the hosts which frequency changed since the functor creation.
+ */
class FrequencyChanged {
std::map<simgrid::s4u::Host*, int> host_list;
public:
- FrequencyChanged(simgrid::s4u::Engine& e) {
+ explicit FrequencyChanged(simgrid::s4u::Engine& e)
+ {
std::vector<simgrid::s4u::Host*> list = e.get_all_hosts();
for (auto& host : list) {
host_list.insert({host, host->get_pstate()});
double get_old_speed(simgrid::s4u::Host* host) { return host_list.at(host); }
};
-class SingleCore {
-public:
- bool operator()(simgrid::s4u::Host* host) { return host->get_core_count() == 1; }
-};
-
-bool filter_speed_more_than_50Mf(simgrid::s4u::Host* host);
-bool filter_speed_more_than_50Mf(simgrid::s4u::Host* host)
-{
- return host->getSpeed() > 50E6;
-}
}
int main(int argc, char* argv[])
{
simgrid::s4u::Engine e(&argc, argv);
e.load_platform(argv[1]);
- /**
- * Use a lambda function to filter hosts: We only want multicore hosts
- */
- XBT_INFO("Hosts currently registered with this engine: %lu", e.get_host_count());
+ /* Use a lambda function to filter hosts: We only want multicore hosts */
+ XBT_INFO("Hosts currently registered with this engine: %zu", e.get_host_count());
std::vector<simgrid::s4u::Host*> list =
- e.get_filtered_hosts([](simgrid::s4u::Host* host) { return host->get_core_count() > 1; });
+ e.get_filtered_hosts([](const simgrid::s4u::Host* host) { return host->get_core_count() > 1; });
for (auto& host : list)
XBT_INFO("The following hosts have more than one core: %s", host->get_cname());
xbt_assert(list.size() == 1);
- /*
- * Use a function object (functor) without memory
- */
+ /* Use a function object (functor) without memory */
list = e.get_filtered_hosts(filter::SingleCore());
for (auto& host : list)
XBT_INFO("The following hosts are SingleCore: %s", host->get_cname());
- /**
- * This just shows how to use a function object that uses
- * memory to filter.
- */
+ /* Use a function object that uses memory to filter */
XBT_INFO("A simple example: Let's retrieve all hosts that changed their frequency");
filter::FrequencyChanged filter(e);
e.host_by_name("MyHost2")->set_pstate(2);
list = e.get_filtered_hosts(filter);
for (auto& host : list)
- XBT_INFO("The following hosts changed their frequency: %s (from %.1ff to %.1ff)", host->get_cname(), host->getPstateSpeed(filter.get_old_speed(host)), host->getSpeed());
+ XBT_INFO("The following hosts changed their frequency: %s (from %.1ff to %.1ff)", host->get_cname(),
+ host->get_pstate_speed(filter.get_old_speed(host)), host->get_speed());
- /*
- * You can also just use any normal function (namespaced as well, if you want) to filter
- */
+ /* You can also just use any regular function (namespaced on need) to filter */
list = e.get_filtered_hosts(filter::filter_speed_more_than_50Mf);
for (auto& host : list)
