tests/open_memstream.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3
   4 #include <darwintest.h>
   5 #include <darwintest_perf.h>
   6
   7 static void
   8 perf_fixed_size(size_t size_per_write)
   9 {
  10         dt_stat_time_t latency = dt_stat_time_create("write_latency",
  11                         "adding %zu bytes to a memstream", size_per_write);
  12         dt_stat_set_variable_d(latency, "bytes", (double)size_per_write);
  13         char *src = calloc(1, size_per_write);
  14         T_QUIET; T_ASSERT_NOTNULL(src, "allocated source buffer");
  15
  16         while (!dt_stat_stable(latency)) {
  17                 char *buf = NULL;
  18                 size_t size = 0;
  19
  20                 FILE *victim = open_memstream(&buf, &size);
  21                 T_QUIET; T_WITH_ERRNO; T_ASSERT_NOTNULL(victim, "opened memstream");
  22
  23                 T_STAT_MEASURE_BATCH(latency) {
  24                         (void)fwrite(src, size_per_write, 1, victim);
  25                 }
  26
  27                 fclose(victim);
  28                 T_QUIET; T_ASSERT_NOTNULL(buf, "buffer was set by open_memstream");
  29                 T_QUIET; T_ASSERT_GE(size, size_per_write,
  30                                 "memstream added non-zero bytes");
  31
  32                 free(buf);
  33         }
  34
  35         free(src);
  36         dt_stat_finalize(latency);
  37 }
  38
  39 T_DECL(perf_open_memstream, "measure the performance of open_memstream")
  40 {
  41         size_t sizes[] = { 1, 8, 16, 64, 1024, 2048, 4096, 16 * 1024 };
  42         for (size_t i = 0; i < sizeof(sizes) / sizeof(sizes[0]); i++) {
  43                 perf_fixed_size(sizes[i]);
  44         }
  45 }