From 899834b5290bf6302a8a01d3c7672a9a200392c7 Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@fb.com>
Date: Fri, 26 Sep 2014 14:57:41 -0600
Subject: [PATCH] bloom: use independent hashes

Signed-off-by: Jens Axboe <axboe@fb.com>
---
 Makefile     |  3 ++-
 crc/xxhash.c |  2 +-
 crc/xxhash.h |  2 +-
 lib/bloom.c  | 42 ++++++++++++++++++++++++++++++++++++------
 4 files changed, 40 insertions(+), 9 deletions(-)

diff --git a/Makefile b/Makefile
index d93ce780..8c424e3d 100644
--- a/Makefile
+++ b/Makefile
@@ -192,7 +192,8 @@ endif
 ifeq ($(CONFIG_TARGET_OS), Linux)
 T_DEDUPE_OBJS = t/dedupe.o
 T_DEDUPE_OBJS += lib/rbtree.o t/log.o mutex.o smalloc.o gettime.o crc/md5.o \
-		memalign.o lib/bloom.o t/debug.o
+		memalign.o lib/bloom.o t/debug.o crc/xxhash.o crc/crc32c.o \
+		crc/crc32c-intel.o
 T_DEDUPE_PROGS = t/dedupe
 endif
 
diff --git a/crc/xxhash.c b/crc/xxhash.c
index eedaecb4..4736c528 100644
--- a/crc/xxhash.c
+++ b/crc/xxhash.c
@@ -221,7 +221,7 @@ static uint32_t XXH32_endian_align(const void* input, int len, uint32_t seed, XX
 }
 
 
-uint32_t XXH32(const void* input, int len, uint32_t seed)
+uint32_t XXH32(const void* input, uint32_t len, uint32_t seed)
 {
 #if 0
     // Simple version, good for code maintenance, but unfortunately slow for small inputs
diff --git a/crc/xxhash.h b/crc/xxhash.h
index e80a91d0..8850d208 100644
--- a/crc/xxhash.h
+++ b/crc/xxhash.h
@@ -88,7 +88,7 @@ typedef enum { XXH_OK=0, XXH_ERROR } XXH_errorcode;
 // Simple Hash Functions
 //****************************
 
-unsigned int XXH32 (const void* input, int len, unsigned int seed);
+uint32_t XXH32 (const void* input, uint32_t len, uint32_t seed);
 
 /*
 XXH32() :
diff --git a/lib/bloom.c b/lib/bloom.c
index 9ab89e4b..b469fded 100644
--- a/lib/bloom.c
+++ b/lib/bloom.c
@@ -4,6 +4,8 @@
 #include "bloom.h"
 #include "../hash.h"
 #include "../minmax.h"
+#include "../crc/xxhash.h"
+#include "../crc/crc32c.h"
 
 struct bloom {
 	uint64_t nentries;
@@ -14,7 +16,31 @@ struct bloom {
 #define BITS_PER_INDEX	(sizeof(uint32_t) * 8)
 #define BITS_INDEX_MASK	(BITS_PER_INDEX - 1)
 
-static unsigned int jhash_init[] = { 0, 0x12db635, 0x2a4a53 };
+struct bloom_hash {
+	unsigned int seed;
+	uint32_t (*fn)(const void *, uint32_t, uint32_t);
+};
+
+static uint32_t b_crc32c(const void *buf, uint32_t len, uint32_t seed)
+{
+	return fio_crc32c(buf, len);
+}
+
+struct bloom_hash hashes[] = {
+	{
+		.seed = 0x8989,
+		.fn = jhash,
+	},
+	{
+		.seed = 0x8989,
+		.fn = XXH32,
+	},
+	{
+		.seed = 0,
+		.fn = b_crc32c,
+	},
+};
+
 #define N_HASHES	3
 
 #define MIN_ENTRIES	1073741824UL
@@ -24,6 +50,8 @@ struct bloom *bloom_new(uint64_t entries)
 	struct bloom *b;
 	size_t no_uints;
 
+	crc32c_intel_probe();
+
 	b = malloc(sizeof(*b));
 	b->nentries = entries;
 	no_uints = (entries + BITS_PER_INDEX - 1) / BITS_PER_INDEX;
@@ -46,16 +74,18 @@ void bloom_free(struct bloom *b)
 static int __bloom_check(struct bloom *b, uint32_t *data, unsigned int nwords,
 			 int set)
 {
-	uint32_t hashes[N_HASHES];
+	uint32_t hash[N_HASHES];
 	int i, was_set;
 
-	for (i = 0; i < N_HASHES; i++)
-		hashes[i] = jhash(data, nwords, jhash_init[i]) % b->nentries;
+	for (i = 0; i < N_HASHES; i++) {
+		hash[i] = hashes[i].fn(data, nwords, hashes[i].seed);
+		hash[i] = hash[i] % b->nentries;
+	}
 
 	was_set = 0;
 	for (i = 0; i < N_HASHES; i++) {
-		const unsigned int index = hashes[i] / BITS_PER_INDEX;
-		const unsigned int bit = hashes[i] & BITS_INDEX_MASK;
+		const unsigned int index = hash[i] / BITS_PER_INDEX;
+		const unsigned int bit = hash[i] & BITS_INDEX_MASK;
 
 		if (b->map[index] & (1U << bit))
 			was_set++;
-- 
2.25.1