[PATCH v3] benchtest: malloc tcache hotpath benchtest.

[Wilco Dijkstra]

Hi Cupertino,

This looks much better, a few minor comments below. A question, how solid are
the results of repeated runs on your system? If it still varies a bit, you could try
adding bench_start () from bench-util.c/h - this is used to increase frequency if
you didn't disable frequency scaling.

Cheers,
Wilco

+/* Benchmark duration in seconds.  */
+#define BENCHMARK_DURATION     10

10 seconds is excessive, I'd reduce this to 2-3 seconds.

+/* Allocate and free blocks in a random order.  */
+static size_t
+malloc_benchmark_loop (void)
+{
+  size_t iters = 0;
+  void *elem = NULL;
+
+  while (!timeout)
+    {
+      elem = TEST_FUNC (alloc_size);
+      free (elem);
+      iters++;
+    }
+
+  return iters;
+}

So this measures latency of dependent malloc/free - I think it is more
realistic to measure throughput. It's best to unroll this and either do
4x malloc, 4x free or 4x malloc+free of different block sizes.

+static void usage(const char *name)
+{
+  fprintf (stderr, "%s: <alloc_size>\n", name);
+  exit (1);
+}

Missing line break.

+int
+main (int argc, char **argv)
+{
+  timing_t cur;
+  size_t iters = 0;
+  json_ctx_t json_ctx;
+  double d_total_s, d_total_i;
+  struct sigaction act;
+
+  if (argc == 1)
+    alloc_size = 1024;
+  else if (argc == 2)
+    {
+      long ret;
+
+      errno = 0;
+      ret = strtol(argv[1], NULL, 10);

Space before '('

+
+      if (errno || ret == 0)
+       usage(argv[0]);

And here

+      alloc_size = ret;
+    }
+  else
+    usage(argv[0]);

And here

+  json_init (&json_ctx, 0, stdout);
+
+  json_document_begin (&json_ctx);
+
+  json_attr_string (&json_ctx, "timing_type", TIMING_TYPE);
+
+  json_attr_object_begin (&json_ctx, "functions");
+
+  json_attr_object_begin (&json_ctx, TEST_NAME);
+
+  json_attr_object_begin (&json_ctx, "");
+
+  memset (&act, 0, sizeof (act));
+  act.sa_handler = &alarm_handler;
+
+  sigaction (SIGALRM, &act, NULL);
+
+  alarm (BENCHMARK_DURATION);
+
+  cur = do_benchmark (&iters);
+
+  struct rusage usage;
+  getrusage(RUSAGE_SELF, &usage);

Dead code...

+  d_total_s = cur;
+  d_total_i = iters;
+
+  json_attr_double (&json_ctx, "duration", d_total_s);
+  json_attr_double (&json_ctx, "iterations", d_total_i);
+  json_attr_double (&json_ctx, "time_per_iteration", d_total_s / d_total_i);
+
+  json_attr_object_end (&json_ctx);
+
+  json_attr_object_end (&json_ctx);
+
+  json_attr_object_end (&json_ctx);
+
+  json_document_end (&json_ctx);
+
+  return 0;
+}
--
2.39.5