1 files changed, 60 insertions, 0 deletions
diff --git a/debian/patches/0002-libihash-use-an-integer-hash-function-on-the-keys.patch b/debian/patches/0002-libihash-use-an-integer-hash-function-on-the-keys.patch
new file mode 100644
index 00000000..820d0869
--- /dev/null
+++ b/debian/patches/0002-libihash-use-an-integer-hash-function-on-the-keys.patch
@@ -0,0 +1,60 @@
+From 2d898893815a980f1b821fcec267eb8e7ded678e Mon Sep 17 00:00:00 2001
+From: Justus Winter <4winter@informatik.uni-hamburg.de>
+Date: Thu, 8 May 2014 15:45:00 +0200
+Subject: [PATCH 02/15] libihash: use an integer hash function on the keys
+
+Use an integer hash function to derive the index from the key.  This
+should reduce the number of collisions.
+
+* libihash/ihash.c (hash_int32): New function.
+(find_index): Use hash_int32 on the key to derive the index.
+(add_one): Likewise.
+---
+ libihash/ihash.c | 17 +++++++++++++++--
+ 1 file changed, 15 insertions(+), 2 deletions(-)
+
+diff --git a/libihash/ihash.c b/libihash/ihash.c
+index d670fee..71ddc26 100644
+--- a/libihash/ihash.c
++++ b/libihash/ihash.c
+@@ -81,6 +81,19 @@ static const unsigned int ihash_nsizes = (sizeof ihash_sizes
+ 					  / sizeof ihash_sizes[0]);
+ 
+ 
++/* This is the integer finalizer from MurmurHash3.  */
++static inline uint32_t
++murmur3_mix32 (uint32_t h, unsigned int bits)
++{
++  h ^= h >> 16;
++  h *= 0x85ebca6b;
++  h ^= h >> 13;
++  h *= 0xc2b2ae35;
++  h ^= h >> 16;
++
++  return h >> (32 - bits);
++}
++
+ /* Return 1 if the slot with the index IDX in the hash table HT is
+    empty, and 0 otherwise.  */
+ static inline int
+@@ -111,7 +124,7 @@ find_index (hurd_ihash_t ht, hurd_ihash_key_t key)
+   unsigned int up_idx;
+   unsigned int down_idx;
+ 
+-  idx = key % ht->size;
++  idx = murmur3_mix32 (key, 32) % ht->size;
+ 
+   if (ht->items[idx].value == _HURD_IHASH_EMPTY || ht->items[idx].key == key)
+     return idx;
+@@ -264,7 +277,7 @@ add_one (hurd_ihash_t ht, hurd_ihash_key_t key, hurd_ihash_value_t value)
+   unsigned int idx;
+   unsigned int first_free;
+ 
+-  idx = key % ht->size;
++  idx = murmur3_mix32 (key, 32) % ht->size;
+   first_free = idx;
+ 
+   if (ht->items[idx].value != _HURD_IHASH_EMPTY && ht->items[idx].key != key)
+-- 
+2.0.0.rc0
+