htable: benchmark against hsearch(3)
authorRusty Russell <rusty@rustcorp.com.au>
Tue, 27 Sep 2011 06:28:44 +0000 (15:58 +0930)
committerRusty Russell <rusty@rustcorp.com.au>
Tue, 27 Sep 2011 06:28:44 +0000 (15:58 +0930)
Since that has a fixed hash table size and doesn't support delete, we can't
do a thorough comparison, but we can insert and search.

ccan/htable/tools/Makefile
ccan/htable/tools/hsearchspeed.c [new file with mode: 0644]
ccan/htable/tools/stringspeed.c

index 289d92b33532a8b09b8ba5e608f8102c7de86f5e..a21c51cb55ea12819a050984dc2d35feeaf89406 100644 (file)
@@ -1,7 +1,7 @@
 CFLAGS=-Wall -Werror -O3 -I../../..
 #CFLAGS=-Wall -Werror -g -I../../..
 
-all: speed stringspeed
+all: speed stringspeed hsearchspeed
 
 speed: speed.o hash.o
 
@@ -14,5 +14,7 @@ stringspeed: stringspeed.o hash.o ../../talloc.o ../../str_talloc.o ../../grab_f
 
 stringspeed.o: speed.c ../htable.h ../htable.c
 
+hsearchspeed: hsearchspeed.o ../../talloc.o ../../str_talloc.o ../../grab_file.o ../../str.o ../../time.o ../../noerr.o
+
 clean:
-       rm -f stringspeed speed
+       rm -f stringspeed speed hsearchspeed *.o
diff --git a/ccan/htable/tools/hsearchspeed.c b/ccan/htable/tools/hsearchspeed.c
new file mode 100644 (file)
index 0000000..ea1a3f5
--- /dev/null
@@ -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;
+}
index 2bc1524ea09d040b8786b14f0c37ea8f64079eec..53ac4da650a377a0f0b27e8f74f83b2828664ac0 100644 (file)
@@ -59,6 +59,7 @@ int main(int argc, char *argv[])
                                         NULL), "\n");
        htable_str_init(&ht);
        num = talloc_array_length(words) - 1;
+       /* Note that on my system, num is just > 98304, where we double! */
        printf("%zu words\n", num);
 
        /* Append and prepend last char for miss testing. */