Allow performance models to have bigger variation: 50% instead of just 10%

configure.ac

@@ -1681,7 +1681,7 @@ AC_LANG_POP([C++])
 AC_MSG_CHECKING(calibration heuristic of history-based StarPU calibrator)
 AC_ARG_ENABLE(calibration-heuristic, [AS_HELP_STRING([--enable-calibration-heuristic=<number>],
 			[Define the maximum authorized deviation of StarPU history-based calibrator.])],
-			calibration_heuristic=$enableval, calibration_heuristic=10)
+			calibration_heuristic=$enableval, calibration_heuristic=50)
 AC_MSG_RESULT($calibration_heuristic)
 AC_DEFINE_UNQUOTED(STARPU_HISTORYMAXERROR, [$calibration_heuristic], [calibration heuristic value])
 

doc/doxygen/chapters/40environment_variables.doxy

@@ -608,7 +608,7 @@ properly, without performing the actual application-provided computation.
 \addindex __env__STARPU_HISTORY_MAX_ERROR
 History-based performance models will drop measurements which are really far
 froom the measured average. This specifies the allowed variation. The default is
-10 (%), i.e. the measurement is allowed to be x1.1 faster or /1.1 slower than the
+50 (%), i.e. the measurement is allowed to be x1.5 faster or /1.5 slower than the
 average.
 </dd>