X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/4b69fae1b624d9a739068fc9629953fc2044c3dd..19284c10d59accc201e72bed4bb717d0fce96f4b:/docs/source/Modeling_howtos.rst diff --git a/docs/source/Modeling_howtos.rst b/docs/source/Modeling_howtos.rst index d17d765666..3772a67904 100644 --- a/docs/source/Modeling_howtos.rst +++ b/docs/source/Modeling_howtos.rst @@ -56,49 +56,6 @@ Unsupported claims, (6) Toy duck approach, and (7) The tunnel view. As you can see, this article is a must read. It's a pity that it's not freely available, though. -.. _howto_calibration: - -Getting realistic results -************************* - -The simulation models in SimGrid have been developed with care and the -object of thorough validation/invalidation campaigns. These models -come with parameters that configure their behaviors. The values of -these parameters are set based on the :ref:`XML platform description -file ` and on parameters passed via :ref:`--cfg=Item:Value -command-line arguments `. A simulator may also include any -number of custom model parameters that are used to instantiate -particular simulated activities (e.g., a simulator developed with the -S4U API typically defines volumes of computation, communication, and -time to pass to methods such as :cpp:func:`execute() -`, :cpp:func:`put() -`, or :cpp:func:`sleep_for() -`). Regardless of the potential -accuracy of the simulation models, if they are instantiated with -unrealistic parameter values, then the simulation will be inaccurate. -The provided default values may or may not be appropriate for -simulating a particular system. - -Given the above, an integral and crucial part of simulation-driven -research is **simulation calibration**: the process by which one picks -simulation parameter values based on observed real-world executions so -that simulated executions have high accuracy. We then say that a -simulator is "calibrated". Once a simulator is calibrated for a -real-world system, it can be used to simulate that system accurately. -But it can also be used to simulate different but structurally -similar systems (e.g., different scales, different basic hardware -characteristics, different application workloads) with high confidence. - -Research conclusions derived from simulation results obtained with an -uncalibrated simulator are questionable in terms of their relevance -for real-world systems. Unfortunately, because simulation calibration -is often a painstaking process, is it often not performed sufficiently -thoroughly (or at all!). We strongly urge SimGrid users to perform -simulation calibration. Here is an example of a research publication -in which the authors have calibrated their (SimGrid) simulators: -https://hal.inria.fr/hal-01523608 - - .. _howto_churn: Modeling churn (e.g., in P2P) @@ -289,6 +246,3 @@ So the final platform for our example becomes : -.. include:: tuto_disk/analysis.irst - -.. include:: tuto_network_calibration/network_calibration_tutorial.rst