htable: benchmark against hsearch(3)

[ccan] / ccan / htable / tools / hsearchspeed.c

diff --git a/ccan/htable/tools/hsearchspeed.c b/ccan/htable/tools/hsearchspeed.c
new file mode 100644 (file)
index 0000000..ea1a3f5
--- /dev/null
+++ b/ccan/htable/tools/hsearchspeed.c
@@ -0,0 +1,103 @@
+/* Simple speed tests for a hash of strings using hsearch */
+#include <ccan/htable/htable_type.h>
+#include <ccan/htable/htable.c>
+#include <ccan/str_talloc/str_talloc.h>
+#include <ccan/grab_file/grab_file.h>
+#include <ccan/talloc/talloc.h>
+#include <ccan/hash/hash.h>
+#include <ccan/time/time.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+#include <sys/time.h>
+#include <search.h>
+
+/* Nanoseconds per operation */
+static size_t normalize(const struct timeval *start,
+                       const struct timeval *stop,
+                       unsigned int num)
+{
+       struct timeval diff;
+
+       timersub(stop, start, &diff);
+
+       /* Floating point is more accurate here. */
+       return (double)(diff.tv_sec * 1000000 + diff.tv_usec)
+               / num * 1000;
+}
+
+int main(int argc, char *argv[])
+{
+       size_t i, j, num;
+       struct timeval start, stop;
+       char **w;
+       ENTRY *words, *misswords;
+
+       w = strsplit(NULL, grab_file(NULL,
+                                    argv[1] ? argv[1] : "/usr/share/dict/words",
+                                    NULL), "\n");
+       num = talloc_array_length(w) - 1;
+       printf("%zu words\n", num);
+
+       hcreate(num+num/3);
+
+       words = talloc_array(w, ENTRY, num);
+       for (i = 0; i < num; i++) {
+               words[i].key = w[i];
+               words[i].data = words[i].key;
+       }
+
+       /* Append and prepend last char for miss testing. */
+       misswords = talloc_array(w, ENTRY, num);
+       for (i = 0; i < num; i++) {
+               char lastc;
+               if (strlen(w[i]))
+                       lastc = w[i][strlen(w[i])-1];
+               else
+                       lastc = 'z';
+               misswords[i].key = talloc_asprintf(misswords, "%c%s%c%c",
+                                                  lastc, w[i],
+                                                  lastc, lastc);
+       }
+
+       printf("#01: Initial insert: ");
+       fflush(stdout);
+       start = time_now();
+       for (i = 0; i < num; i++)
+               hsearch(words[i], ENTER);
+       stop = time_now();
+       printf(" %zu ns\n", normalize(&start, &stop, num));
+
+       printf("#02: Initial lookup (match): ");
+       fflush(stdout);
+       start = time_now();
+       for (i = 0; i < num; i++)
+               if (hsearch(words[i], FIND)->data != words[i].data)
+                       abort();
+       stop = time_now();
+       printf(" %zu ns\n", normalize(&start, &stop, num));
+
+       printf("#03: Initial lookup (miss): ");
+       fflush(stdout);
+       start = time_now();
+       for (i = 0; i < num; i++) {
+               if (hsearch(misswords[i], FIND))
+                       abort();
+       }
+       stop = time_now();
+       printf(" %zu ns\n", normalize(&start, &stop, num));
+
+       /* Lookups in order are very cache-friendly for judy; try random */
+       printf("#04: Initial lookup (random): ");
+       fflush(stdout);
+       start = time_now();
+       for (i = 0, j = 0; i < num; i++, j = (j + 10007) % num)
+               if (hsearch(words[i], FIND)->data != words[i].data)
+                       abort();
+       stop = time_now();
+       printf(" %zu ns\n", normalize(&start, &stop, num));
+
+       return 0;
+}