opr_convect_scalar.cu

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/*
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#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include "convect_scalar_kernel.h"
#include "elem_block_tune.h"
#include <device/device_config.h>
#include <device/cuda/check.h>
 
extern "C" {
  #include <common/neko_log.h>
}
 
template < const int >
int tune_convect_scalar(void *du, void *u,
               void *cr, void *cs, void *ct,
               void *dx, void *dy, void *dz,
               int *nel, int *lx, int *eb_sel, int *ch_sel);
 
extern "C" {
 
  void cuda_convect_scalar(void *du, void *u,
                  void *cr, void *cs, void *ct,
                  void *dx, void *dy, void *dz,
                  int *nel, int *lx) {
 
    static int autotune[17] = { 0 };
    /* elements per block candidate chosen by the tuner */
    static int autotune_eb[17] = { 0 };
    /* chunk candidate chosen for the 1d variant */
    static int autotune_ch[17] = { 0 };
 
    const dim3 nthrds_1d(1024, 1, 1);
    const dim3 nthrds_kstep((*lx), (*lx), 1);
    const dim3 nblcks((*nel), 1, 1);
    const cudaStream_t stream = (cudaStream_t) glb_cmd_queue;
 
#define CASE_1D(LX, C)                                                          \
    convect_scalar_kernel_1d<real, LX, NEKO_CHUNKS(LX, C)>                      \
      <<<nblcks, NEKO_CHUNKS_NTHRDS(LX, C), 0, stream>>>                        \
      ((real *) du, (real *) u,                                                 \
       (real *) cr, (real *) cs, (real *) ct,                                   \
       (real *) dx, (real *) dy, (real *) dz);                                  \
    CUDA_CHECK(cudaGetLastError());
 
/* Runtime dispatch onto the tuned chunk candidate */
#define CASE_1D_SEL(LX, SEL)                                                    \
    switch (SEL) {                                                              \
    case 0:  CASE_1D(LX, 0); break;                                             \
    case 1:  CASE_1D(LX, 1); break;                                             \
    case 2:  CASE_1D(LX, 2); break;                                             \
    default: CASE_1D(LX, 3); break;                                             \
    }
 
#define CASE_KSTEP(LX, C)                                                       \
    convect_scalar_kernel_kstep<real, LX, NEKO_EB(LX, C)>                       \
      <<<NEKO_EB_NBLCKS(*nel, LX, C), NEKO_EB_NTHRDS(LX, C), 0, stream>>>       \
      ((real *) du, (real *) u,                                                 \
       (real *) cr, (real *) cs, (real *) ct,                                   \
       (real *) dx, (real *) dy, (real *) dz, *nel);                            \
    CUDA_CHECK(cudaGetLastError());
 
/* Runtime dispatch onto the tuned candidate */
#define CASE_KSTEP_SEL(LX, SEL)                                                 \
    switch (SEL) {                                                              \
    case 0:  CASE_KSTEP(LX, 0); break;                                          \
    case 1:  CASE_KSTEP(LX, 1); break;                                          \
    default: CASE_KSTEP(LX, 2); break;                                          \
    }
 
#define CASE(LX)                                                                \
    case LX:                                                                    \
      if(autotune[LX] == 0 ) {                                                  \
        autotune[LX]=tune_convect_scalar<LX>(du, u,                             \
                                    cr, cs, ct,                                 \
                                    dx, dy, dz,                                 \
                                    nel, lx, &autotune_eb[LX],                  \
                                    &autotune_ch[LX]);                          \
      } else if (autotune[LX] == 1 ) {                                          \
        CASE_1D_SEL(LX, autotune_ch[LX]);                                       \
      } else if (autotune[LX] == 2 ) {                                          \
        CASE_KSTEP_SEL(LX, autotune_eb[LX]);                                    \
      }                                                                         \
      break
 
#define CASE_LARGE(LX)                                                          \
    case LX:                                                                    \
      CASE_KSTEP(LX, 0);                                                        \
      break
 
 
    if ((*lx) < 11) {
      switch(*lx) {
        CASE(2);
        CASE(3);
        CASE(4);
        CASE(5);
        CASE(6);
        CASE(7);
        CASE(8);
        CASE(9);
        CASE(10);
      default:
        {
          fprintf(stderr, __FILE__ ": size not supported: %d\n", *lx);
          exit(1);
        }
      }
    }
    else {
      switch(*lx) {
        CASE_LARGE(11);
        CASE_LARGE(12);
        CASE_LARGE(13);
        CASE_LARGE(14);
        CASE_LARGE(15);
        CASE_LARGE(16);
      default:
        {
          fprintf(stderr, __FILE__ ": size not supported: %d\n", *lx);
          exit(1);
        }
      }
    }
  }
}
 
template < const int LX >
int tune_convect_scalar(void *du, void *u,
               void *cr, void *cs, void *ct,
               void *dx, void *dy, void *dz,
               int *nel, int *lx, int *eb_sel, int *ch_sel) {
  cudaEvent_t start,stop;
  float time1[NEKO_CHUNKS_CANDIDATES];
  int best1 = 0;
  float time2[NEKO_EB_CANDIDATES];
  const int rounds = neko_tune_rounds();
  const int iters = neko_tune_iters();
  /* Candidates of the kstep sweep, one -- the unblocked shape -- when the
     elements per block sweep is off */
  const int eb_cand = neko_eb_sweep() ? NEKO_EB_CANDIDATES : 1;
  /* Geometry pinned by each formulation's own variable, -1 to sweep it */
  const int ch_pin = neko_chunks_pin();
  const int eb_pin = neko_eb_pin();
  /* Formulation pinned by NEKO_AUTOTUNE, as the identifier this returns */
  int strat = 0;
  int best = 0;
  int retval;
 
  for (int c = 0; c < NEKO_EB_CANDIDATES; c++) {
    time2[c] = NEKO_TUNE_INIT;
  }
  for (int c = 0; c < NEKO_CHUNKS_CANDIDATES; c++) {
    time1[c] = NEKO_TUNE_INIT;
  }
 
  const dim3 nthrds_1d(1024, 1, 1);
  const dim3 nthrds_kstep((*lx), (*lx), 1);
  const dim3 nblcks((*nel), 1, 1);
  const cudaStream_t stream = (cudaStream_t) glb_cmd_queue;
 
  char *env_value = NULL;
  char neko_log_buf[80];
 
  env_value=getenv("NEKO_AUTOTUNE");
 
  sprintf(neko_log_buf, "Autotune convect_scalar (lx: %d)", *lx);
  log_section(neko_log_buf);
 
  *eb_sel = 0;
  *ch_sel = 0;
 
  /*
   * NEKO_AUTOTUNE names a formulation, and that is all it does: the sweep
   * below is narrowed to that one kernel family, but its geometry -- the
   * chunk size, the elements per block -- is still measured candidate
   * against candidate.
   */
  if(env_value) {
    if( !strcmp(env_value,"1D") ) {
      strat = 1;
    } else if( !strcmp(env_value,"KSTEP") ) {
      strat = 2;
    } else {
       sprintf(neko_log_buf, "Invalid value set for NEKO_AUTOTUNE");
       log_error(neko_log_buf);
    }
  }
 
  /* Geometry of the pinned formulation, if its own variable fixes that too.
     Both pinned leaves nothing to measure, so the kernel is launched once and
     reported, which is what pinning has always done */
  const int pin = (strat == 1) ? ch_pin : (strat == 2) ? eb_pin : -1;
 
  if (pin >= 0) {
    switch (strat) {
    case 1:
      *ch_sel = pin;
      CASE_1D_SEL(LX, pin);
      sprintf(neko_log_buf, "Set by env   : 1 (1D, %d chunk)",
              NEKO_CHUNKS_SEL(LX, pin));
      break;
    default:
      *eb_sel = pin;
      CASE_KSTEP_SEL(LX, pin);
      sprintf(neko_log_buf, "Set by env   : 2 (KSTEP, %d elem/block)",
              NEKO_EB_SEL(LX, pin));
      break;
    }
    log_message(neko_log_buf);
    log_end_section();
    return strat;
  }
 
  if (strat) {
    sprintf(neko_log_buf, "Set by env   : %d (%s)", strat, env_value);
    log_message(neko_log_buf);
  }
 
  /* Formulations the sweep considers, see NEKO_TUNE_FOR() */
  const bool try_1d = (strat == 0 || strat == 1);
  const bool try_kstep = (strat == 0 || strat == 2);
 
  cudaEventCreate(&start);
  cudaEventCreate(&stop);
  /* Warm every variant before timing anything: each specialisation has to be
     resident and the clocks at steady state, or whichever is timed first is
     measured on a colder part */
  for (int i = 0; i < NEKO_TUNE_WARMUP; i++) {
    NEKO_TUNE_FOR(c, try_1d, ch_pin, NEKO_CHUNKS_CANDIDATES) {
      CASE_1D_SEL(LX, c);
    }
    NEKO_TUNE_FOR(c, try_kstep, eb_pin, eb_cand) {
      CASE_KSTEP_SEL(LX, c);
    }
  }
 
  /* Interleaved rounds, best time per variant */
  for (int r = 0; r < rounds; r++) {
    NEKO_TUNE_FOR(c, try_1d, ch_pin, NEKO_CHUNKS_CANDIDATES) {
      NEKO_TUNE_TIME(time1, CASE_1D_SEL, LX, c, iters);
    }
    NEKO_TUNE_FOR(c, try_kstep, eb_pin, eb_cand) {
      NEKO_TUNE_TIME(time2, CASE_KSTEP_SEL, LX, c, iters);
    }
  }
 
  NEKO_TUNE_LOG(LX, time1, time2);
  NEKO_TUNE_BEST(time1, best1, NEKO_CHUNKS_CANDIDATES);
  NEKO_TUNE_BEST(time2, best, NEKO_EB_CANDIDATES);
  *eb_sel = best;
  *ch_sel = best1;
 
  if (time1[best1] < time2[best]) {
    retval = 1;
  } else {
    retval = 2;
  }
 
  /* Leave the chosen kernel's output in place: the tuner stands in for a real
     evaluation and the variants do not sum in the same order */
  if (retval == 1) {
    CASE_1D_SEL(LX, best1);
  } else {
    CASE_KSTEP_SEL(LX, best);
  }
 
  if (retval == 1) {
    sprintf(neko_log_buf, "Chose        : 1 (1D, %d chunk)",
            NEKO_CHUNKS_SEL(LX, best1));
  } else {
    sprintf(neko_log_buf, "Chose        : 2 (KSTEP, %d elem/block)",
            NEKO_EB_SEL(LX, best));
  }
  log_message(neko_log_buf);
  log_end_section();
  return retval;
}