tune.c File Reference

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Detailed Description

Tuning module implementation.

Current list of heuristics:

• Cache blocked SpMV
• Register blocked SpMV
• Register blocked sparse .
• Register blocked, switch-to-dense triangular solve

Basic structure of a heuristic:

• Has two associated cost estimates
  1. time to run heuristic,
  2. time to convert.
• Here's a typical implementation of a heuristic:
  

  FUNCTION HeurType :: EvaluateHeuristic( heur:HeurType, A:matrix )
      IF this heuristic does not apply to A and its trace THEN
          RETURN NULL;
      ENDIF
  
      LET results = Choose tuning parameters for A
      RETURN results
  

  
  For example, here is the heuristic for register blocked SpMV:
  

  FUNCTION RBSpMV :: EvaluateHeuristic( heur:HeurType, A:matrix )
      IF A->trace not "dominated" by calls to SpMV THEN
          RETURN NULL;
      ENDIF
  
      LET EstFill[MAX_R, MAX_C] = EstimateFill( A )
      LET Mflops_dense[MAX_R, MAX_C] = LoadRegProfile( A )
  
      LET r, c = max_{r,c} Mflops_dense[r,c] / EstFill[r, c]
  
      IF r == 1 AND c == 1 THEN
          RETURN NULL;
      ELSE
          LET results = new RbSpMV_results( r, c )
          RETURN results
      ENDIF
  

#include <math.h>
#include <oski/common.h>
#include <oski/simplelist.h>
#include <oski/heur_internal.h>
#include <oski/heur_typedep.h>
#include <oski/heurexport.h>
#include <oski/trace.h>
#include <oski/tune.h>
#include <oski/timer.h>
#include <oski/matrix.h>
#include <oski/vecview.h>
#include <oski/xforms.h>

Defines
#define	BEST_FRAC_OBSERVED   .25
	Fraction of observed workload available for tuning.
#define	BEST_FRAC_WORKLOAD   .25
	Fraction of hint workload available for tuning.
Functions
static double	ComputeTuningBudget (oski_matrix_t A_tunable)
	Returns the estimated number of seconds available for tuning.
static int	ChooseFastest (oski_matrix_t A_tunable)
	Determines whether the heuristic-selected data structure leads to faster execution times than the input data structure.
static void	FreeTunedMat (oski_matrix_t A_tunable)
int	oski_TuneMat (oski_matrix_t A_tunable)
	Tune the matrix object using all hints and implicit profiling data.

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Function Documentation

static int ChooseFastest (  oski_matrix_t  A_tunable  )  [static]

Determines whether the heuristic-selected data structure leads to faster execution times than the input data structure. Returns: 1 if the tuned implementation is faster, and 0 otherwise. Todo: Implement this routine, given that we will need to allocate temporary vectors.

static double ComputeTuningBudget (  oski_matrix_t  A_tunable  )  [static]

Returns the estimated number of seconds available for tuning. The estimate is based on the larger of the following two quantities: Estimated time to execute the trace determined by the workload hints. The actual accumulated kernel execution time so far.

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