ceph/src/seastar/dpdk/app/test/test_reciprocal_division_perf.c

   1 /* SPDX-License-Identifier: BSD-3-Clause
   2  * Copyright(c) 2017 Cavium, Inc
   3  */
   4
   5 #include "test.h"
   6
   7 #include <stdio.h>
   8 #include <unistd.h>
   9 #include <inttypes.h>
  10
  11 #include <rte_common.h>
  12 #include <rte_cycles.h>
  13 #include <rte_random.h>
  14 #include <rte_reciprocal.h>
  15
  16 #define MAX_ITERATIONS  (1ULL << 32)
  17 #define DIVIDE_ITER     (1ULL << 28)
  18
  19 static int
  20 test_reciprocal_division_perf(void)
  21 {
  22         int result = 0;
  23         uint32_t divisor_u32 = 0;
  24         uint32_t dividend_u32;
  25         uint64_t divisor_u64 = 0;
  26         uint64_t dividend_u64;
  27         volatile uint32_t nresult_u32;
  28         volatile uint32_t rresult_u32;
  29         volatile uint64_t nresult_u64;
  30         volatile uint64_t rresult_u64;
  31         uint64_t start_cyc;
  32         uint64_t split_cyc;
  33         uint64_t end_cyc;
  34         uint64_t tot_cyc_n = 0;
  35         uint64_t tot_cyc_r = 0;
  36         uint64_t i;
  37         struct rte_reciprocal reci_u32 = {0};
  38         struct rte_reciprocal_u64 reci_u64 = {0};
  39
  40         rte_srand(rte_rdtsc());
  41
  42         printf("Validating unsigned 32bit division.\n");
  43         for (i = 0; i < MAX_ITERATIONS; i++) {
  44                 /* Change divisor every DIVIDE_ITER iterations. */
  45                 if (i % DIVIDE_ITER == 0) {
  46                         divisor_u32 = rte_rand();
  47                         reci_u32 = rte_reciprocal_value(divisor_u32);
  48                 }
  49
  50                 dividend_u32 = rte_rand();
  51
  52                 start_cyc = rte_rdtsc();
  53                 nresult_u32 = dividend_u32 / divisor_u32;
  54                 split_cyc = rte_rdtsc();
  55                 rresult_u32 = rte_reciprocal_divide(dividend_u32,
  56                                 reci_u32);
  57                 end_cyc = rte_rdtsc();
  58
  59                 tot_cyc_n += split_cyc - start_cyc;
  60                 tot_cyc_r += end_cyc - split_cyc;
  61                 if (nresult_u32 != rresult_u32) {
  62                         printf("Division failed, expected %"PRIu32" "
  63                                         "result %"PRIu32"",
  64                                         nresult_u32, rresult_u32);
  65                         result = 1;
  66                         break;
  67                 }
  68         }
  69         printf("32bit Division results:\n");
  70         printf("Total number of cycles normal division     : %"PRIu64"\n",
  71                         tot_cyc_n);
  72         printf("Total number of cycles reciprocal division : %"PRIu64"\n",
  73                         tot_cyc_r);
  74         printf("Cycles per division(normal) : %3.2f\n",
  75                         ((double)tot_cyc_n)/i);
  76         printf("Cycles per division(reciprocal) : %3.2f\n\n",
  77                         ((double)tot_cyc_r)/i);
  78
  79         tot_cyc_n = 0;
  80         tot_cyc_r = 0;
  81
  82         printf("Validating unsigned 64bit division.\n");
  83         for (i = 0; i < MAX_ITERATIONS; i++) {
  84                 /* Change divisor every DIVIDE_ITER iterations. */
  85                 if (i % DIVIDE_ITER == 0) {
  86                         divisor_u64 = rte_rand();
  87                         reci_u64 = rte_reciprocal_value_u64(divisor_u64);
  88                 }
  89
  90                 dividend_u64 = rte_rand();
  91
  92                 start_cyc = rte_rdtsc();
  93                 nresult_u64 = dividend_u64 / divisor_u64;
  94                 split_cyc = rte_rdtsc();
  95                 rresult_u64 = rte_reciprocal_divide_u64(dividend_u64,
  96                                 &reci_u64);
  97                 end_cyc = rte_rdtsc();
  98
  99                 tot_cyc_n += split_cyc - start_cyc;
 100                 tot_cyc_r += end_cyc - split_cyc;
 101                 if (nresult_u64 != rresult_u64) {
 102                         printf("Division failed, expected %"PRIu64" "
 103                                         "result %"PRIu64"",
 104                                         nresult_u64, rresult_u64);
 105                         result = 1;
 106                         break;
 107                 }
 108         }
 109         printf("64bit Division results:\n");
 110         printf("Total number of cycles normal division     : %"PRIu64"\n",
 111                         tot_cyc_n);
 112         printf("Total number of cycles reciprocal division : %"PRIu64"\n",
 113                         tot_cyc_r);
 114         printf("Cycles per division(normal) : %3.2f\n",
 115                         ((double)tot_cyc_n)/i);
 116         printf("Cycles per division(reciprocal) : %3.2f\n\n",
 117                         ((double)tot_cyc_r)/i);
 118
 119         tot_cyc_n = 0;
 120         tot_cyc_r = 0;
 121
 122         printf("Validating unsigned 64bit division with 32bit divisor.\n");
 123         for (i = 0; i < MAX_ITERATIONS; i++) {
 124                 /* Change divisor every DIVIDE_ITER iterations. */
 125                 if (i % DIVIDE_ITER == 0) {
 126                         divisor_u64 = rte_rand() >> 32;
 127                         reci_u64 = rte_reciprocal_value_u64(divisor_u64);
 128                 }
 129
 130                 dividend_u64 = rte_rand();
 131
 132                 start_cyc = rte_rdtsc();
 133                 nresult_u64 = dividend_u64 / divisor_u64;
 134                 split_cyc = rte_rdtsc();
 135                 rresult_u64 = rte_reciprocal_divide_u64(dividend_u64,
 136                                 &reci_u64);
 137                 end_cyc = rte_rdtsc();
 138
 139                 tot_cyc_n += split_cyc - start_cyc;
 140                 tot_cyc_r += end_cyc - split_cyc;
 141                 if (nresult_u64 != rresult_u64) {
 142                         printf("Division failed, expected %"PRIu64" "
 143                                         "result %"PRIu64"",
 144                                         nresult_u64, rresult_u64);
 145                         result = 1;
 146                         break;
 147                 }
 148         }
 149
 150         printf("64bit Division results:\n");
 151         printf("Total number of cycles normal division     : %"PRIu64"\n",
 152                         tot_cyc_n);
 153         printf("Total number of cycles reciprocal division : %"PRIu64"\n",
 154                         tot_cyc_r);
 155         printf("Cycles per division(normal) : %3.2f\n",
 156                         ((double)tot_cyc_n)/i);
 157         printf("Cycles per division(reciprocal) : %3.2f\n\n",
 158                         ((double)tot_cyc_r)/i);
 159
 160         tot_cyc_n = 0;
 161         tot_cyc_r = 0;
 162
 163         printf("Validating division by power of 2.\n");
 164         for (i = 0; i < 64; i++) {
 165                 divisor_u64 = 1ull << i;
 166                 reci_u64 = rte_reciprocal_value_u64(divisor_u64);
 167
 168                 dividend_u64 = rte_rand();
 169
 170                 start_cyc = rte_rdtsc();
 171                 nresult_u64 = dividend_u64 / divisor_u64;
 172                 split_cyc = rte_rdtsc();
 173                 rresult_u64 = rte_reciprocal_divide_u64(dividend_u64,
 174                                 &reci_u64);
 175                 end_cyc = rte_rdtsc();
 176
 177                 tot_cyc_n += split_cyc - start_cyc;
 178                 tot_cyc_r += end_cyc - split_cyc;
 179                 if (nresult_u64 != rresult_u64) {
 180                         printf("Division 64 failed, %"PRIu64"/%"PRIu64" = "
 181                                         "expected %"PRIu64" result %"PRIu64"\n",
 182                                         dividend_u64, divisor_u64,
 183                                         nresult_u64, rresult_u64);
 184                         result = 1;
 185                         break;
 186                 }
 187         }
 188         printf("64bit Division results:\n");
 189         printf("Total number of cycles normal division     : %"PRIu64"\n",
 190                         tot_cyc_n);
 191         printf("Total number of cycles reciprocal division : %"PRIu64"\n",
 192                         tot_cyc_r);
 193         printf("Cycles per division(normal) : %3.2f\n",
 194                         ((double)tot_cyc_n)/i);
 195         printf("Cycles per division(reciprocal) : %3.2f\n",
 196                         ((double)tot_cyc_r)/i);
 197
 198         return result;
 199 }
 200
 201 REGISTER_TEST_COMMAND(reciprocal_division_perf, test_reciprocal_division_perf);