+# Copyright (c) 2006-2021. 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.
+
+# This example shows how to simulate a non-linear resource sharing for
+# CPUs.
+
+
+from simgrid import Actor, Engine, NetZone, Host, this_actor
+import sys
+import functools
+
+
+def runner():
+ computation_amount = this_actor.get_host().speed
+ n_task = 10
+
+ this_actor.info("Execute %d tasks of %g flops, should take %d second in a CPU without degradation. It will take the double here." % (
+ n_task, computation_amount, n_task))
+ tasks = [this_actor.exec_init(computation_amount).start()
+ for _ in range(n_task)]
+
+ this_actor.info("Waiting for all tasks to be done!")
+ for task in tasks:
+ task.wait()
+
+ this_actor.info("Finished executing. Goodbye now!")
+
+
+def cpu_nonlinear(host: Host, capacity: float, n: int) -> float:
+ """ Non-linear resource sharing for CPU """
+ # emulates a degradation in CPU according to the number of tasks
+ # totally unrealistic but for learning purposes
+ capacity = capacity / 2 if n > 1 else capacity
+ this_actor.info("Host %s, %d concurrent tasks, new capacity %f" %
+ (host.name, n, capacity))
+ return capacity
+
+
+def load_platform():
+ """ Create a simple 1-host platform """
+ zone = NetZone.create_empty_zone("Zone1")
+ runner_host = zone.create_host("runner", 1e6)
+ runner_host.set_sharing_policy(
+ Host.SharingPolicy.NONLINEAR, functools.partial(cpu_nonlinear, runner_host))
+ runner_host.seal()
+ zone.seal()
+
+ # create actor runner
+ Actor.create("runner", runner_host, runner)
+
+
+if __name__ == '__main__':
+ e = Engine(sys.argv)
+
+ # create platform
+ load_platform()
+
+ # runs the simulation
+ e.run()
+
+ # explicitly deleting Engine object to avoid segfault during cleanup phase.
+ # During Engine destruction, the cleanup of std::function linked to non_linear callback is called.
+ # If we let the cleanup by itself, it fails trying on its destruction because the python main program
+ # has already freed its variables
+ del(e)