tests: test DECLARE_HASH with good and bad hashfn

The hash table test was previously (intentionally) using a bad hash function to test the code in the face of hash collisions. Add a test with a good hash function to see some performance numbers. Signed-off-by: David Lamparter <equinox@diac24.net>
FRRouting · May 21, 2019 · 2214f16 · 2214f16
1 parent fdad523
commit 2214f16
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Showing 3 changed files with 26 additions and 8 deletions.
diff --git a/tests/lib/test_typelist.c b/tests/lib/test_typelist.c
@@ -32,6 +32,7 @@
 #include "atomlist.h"
 #include "memory.h"
 #include "monotime.h"
+#include "jhash.h"
 
 #include "tests/helpers/c/prng.h"
 
@@ -105,6 +106,12 @@ static void ts_end(void)
 #define TYPE HASH
 #include "test_typelist.h"
 
+#define TYPE HASH_collisions
+#define REALTYPE HASH
+#define SHITTY_HASH
+#include "test_typelist.h"
+#undef SHITTY_HASH
+
 #define TYPE SKIPLIST_UNIQ
 #include "test_typelist.h"
 
@@ -130,6 +137,7 @@ int main(int argc, char **argv)
 	test_SORTLIST_UNIQ();
 	test_SORTLIST_NONUNIQ();
 	test_HASH();
+	test_HASH_collisions();
 	test_SKIPLIST_UNIQ();
 	test_SKIPLIST_NONUNIQ();
 	test_RBTREE_UNIQ();

diff --git a/tests/lib/test_typelist.h b/tests/lib/test_typelist.h
@@ -36,7 +36,11 @@
 #define list_del	concat(TYPE, _del)
 #define list_pop	concat(TYPE, _pop)
 
-PREDECL(TYPE, list)
+#ifndef REALTYPE
+#define REALTYPE TYPE
+#endif
+
+PREDECL(REALTYPE, list)
 struct item {
 	uint64_t val;
 	struct list_item itm;
@@ -45,18 +49,22 @@ struct item {
 
 static int list_cmp(const struct item *a, const struct item *b);
 
-#if IS_HASH(TYPE)
+#if IS_HASH(REALTYPE)
 static uint32_t list_hash(const struct item *a);
-DECLARE(TYPE, list, struct item, itm, list_cmp, list_hash)
+DECLARE(REALTYPE, list, struct item, itm, list_cmp, list_hash)
 
 static uint32_t list_hash(const struct item *a)
 {
+#ifdef SHITTY_HASH
 	/* crappy hash to get some hash collisions */
 	return a->val ^ (a->val << 29) ^ 0x55AA0000U;
+#else
+	return jhash_1word(a->val, 0xdeadbeef);
+#endif
 }
 
 #else
-DECLARE(TYPE, list, struct item, itm, list_cmp)
+DECLARE(REALTYPE, list, struct item, itm, list_cmp)
 #endif
 
 static int list_cmp(const struct item *a, const struct item *b)
@@ -70,7 +78,7 @@ static int list_cmp(const struct item *a, const struct item *b)
 
 #define NITEM 10000
 struct item itm[NITEM];
-static struct list_head head = concat(INIT_, TYPE)(head);
+static struct list_head head = concat(INIT_, REALTYPE)(head);
 
 static void concat(test_, TYPE)(void)
 {
@@ -109,7 +117,7 @@ static void concat(test_, TYPE)(void)
 	k = 0;
 	prev = NULL;
 	for_each(list, &head, item) {
-#if IS_HASH(TYPE)
+#if IS_HASH(REALTYPE)
 		/* hash table doesn't give sorting */
 		(void)prev;
 #else
@@ -121,7 +129,7 @@ static void concat(test_, TYPE)(void)
 	assert(list_count(&head) == k);
 	ts_ref("walk");
 
-#if IS_UNIQ(TYPE)
+#if IS_UNIQ(REALTYPE)
 	prng_free(prng);
 	prng = prng_new(0);
 
@@ -175,7 +183,7 @@ static void concat(test_, TYPE)(void)
 	}
 	ts_ref("add-dup+find_{lt,gteq}");
 #endif
-#if !IS_HASH(TYPE)
+#if !IS_HASH(REALTYPE)
 	prng_free(prng);
 	prng = prng_new(123456);
 
@@ -269,4 +277,5 @@ static void concat(test_, TYPE)(void)
 #undef list_del
 #undef list_pop
 
+#undef REALTYPE
 #undef TYPE
diff --git a/tests/lib/test_typelist.py b/tests/lib/test_typelist.py
@@ -6,6 +6,7 @@ class TestTypelist(frrtest.TestMultiOut):
 TestTypelist.onesimple('SORTLIST_UNIQ end')
 TestTypelist.onesimple('SORTLIST_NONUNIQ end')
 TestTypelist.onesimple('HASH end')
+TestTypelist.onesimple('HASH_collisions end')
 TestTypelist.onesimple('SKIPLIST_UNIQ end')
 TestTypelist.onesimple('SKIPLIST_NONUNIQ end')
 TestTypelist.onesimple('RBTREE_UNIQ end')