double samplingRate() { return sampling_rate; }
};
+/**
+ * The linux kernel doc describes this governor as follows:
+ * https://www.kernel.org/doc/Documentation/cpu-freq/governors.txt
+ *
+ * > The CPUfreq governor "performance" sets the CPU statically to the
+ * > highest frequency within the borders of scaling_min_freq and
+ * > scaling_max_freq.
+ *
+ * We do not support scaling_min_freq/scaling_max_freq -- we just pick the lowest frequency.
+ */
class Performance : public Governor {
public:
explicit Performance(simgrid::s4u::Host* ptr) : Governor(ptr) {}
std::string getName() override { return "Performance"; }
};
+/**
+ * The linux kernel doc describes this governor as follows:
+ * https://www.kernel.org/doc/Documentation/cpu-freq/governors.txt
+ *
+ * > The CPUfreq governor "powersave" sets the CPU statically to the
+ * > lowest frequency within the borders of scaling_min_freq and
+ * > scaling_max_freq.
+ *
+ * We do not support scaling_min_freq/scaling_max_freq -- we just pick the lowest frequency.
+ */
class Powersave : public Governor {
public:
explicit Powersave(simgrid::s4u::Host* ptr) : Governor(ptr) {}
std::string getName() override { return "Powersave"; }
};
+/**
+ * The linux kernel doc describes this governor as follows:
+ * https://www.kernel.org/doc/Documentation/cpu-freq/governors.txt
+ *
+ * > The CPUfreq governor "ondemand" sets the CPU frequency depending on the
+ * > current system load. [...] when triggered, cpufreq checks
+ * > the CPU-usage statistics over the last period and the governor sets the
+ * > CPU accordingly.
+ */
class OnDemand : public Governor {
- double freq_up_threshold = 0.95;
+ /**
+ * See https://elixir.bootlin.com/linux/v4.15.4/source/drivers/cpufreq/cpufreq_ondemand.c
+ * DEF_FREQUENCY_UP_THRESHOLD and od_update()
+ */
+ double freq_up_threshold = 0.80;
public:
explicit OnDemand(simgrid::s4u::Host* ptr) : Governor(ptr) {}
}
};
+/**
+ * This is the conservative governor, which is very similar to the
+ * OnDemand governor. The Linux Kernel Documentation describes it
+ * very well, see https://www.kernel.org/doc/Documentation/cpu-freq/governors.txt:
+ *
+ * > The CPUfreq governor "conservative", much like the "ondemand"
+ * > governor, sets the CPU frequency depending on the current usage. It
+ * > differs in behaviour in that it gracefully increases and decreases the
+ * > CPU speed rather than jumping to max speed the moment there is any load
+ * > on the CPU. This behaviour is more suitable in a battery powered
+ * > environment.
+ */
class Conservative : public Governor {
double freq_up_threshold = .8;
double freq_down_threshold = .2;
}
};
+/**
+ * Add this to your host tag:
+ * - <prop id="plugin/dvfs/governor" value="performance" />
+ *
+ * Valid values as of now are: performance, powersave, ondemand, conservative
+ * It doesn't matter if you use uppercase or lowercase.
+ *
+ * For the sampling rate, use this:
+ *
+ * - <prop id="plugin/dvfs/sampling_rate" value="2" />
+ *
+ * This will run the update() method of the specified governor every 2 seconds
+ * on that host.
+ *
+ * These properties can also be used within the <config> tag to configure
+ * these values globally. Using them within the <host> will overwrite this
+ * global configuration
+ */
class HostDvfs {
public:
static simgrid::xbt::Extension<simgrid::s4u::Host, HostDvfs> EXTENSION_ID;