Browse Source

document more about calibration intervals

Samuel Thibault 12 years ago
parent
commit
dcd7e05d25
1 changed files with 13 additions and 0 deletions
  1. 13 0
      doc/doxygen/chapters/advanced_examples.doxy

+ 13 - 0
doc/doxygen/chapters/advanced_examples.doxy

@@ -394,6 +394,19 @@ there is some hidden parameter such as the number of iterations, etc.
 The example in the directory <c>examples/pi</c> uses this to include
 The example in the directory <c>examples/pi</c> uses this to include
 the number of iterations in the base.
 the number of iterations in the base.
 
 
+StarPU will automatically determine when the performance model is calibrated,
+or rather, it will assume the performance model is calibrated until the
+application submits a task for which the performance can not be predicted. For
+::STARPU_HISTORY_BASED, StarPU will require 10 (::_STARPU_CALIBRATION_MINIMUM)
+measurements for a given size before estimating that an average can be taken as
+estimation for further executions with the same size. For
+::STARPU_REGRESSION_BASED and ::STARPU_NL_REGRESSION_BASED, StarPU will require
+10 (::_STARPU_CALIBRATION_MINIMUM) measurements, and that the minimum measured
+data size is smaller than 90% of the maximum measured data size (i.e. the
+measurement interval is large enough for a regression to have a meaning).
+Calibration can also be forced by setting the \ref STARPU_CALIBRATE environment
+variable to <c>1</c>, or even reset by setting it to <c>2</c>.
+
 How to use schedulers which can benefit from such performance model is explained
 How to use schedulers which can benefit from such performance model is explained
 in \ref TaskSchedulingPolicy.
 in \ref TaskSchedulingPolicy.