diff options
Diffstat (limited to 'debian/patches/0004-libihash-use-fast-binary-scaling-to-determine-the-lo.patch')
| -rw-r--r-- | debian/patches/0004-libihash-use-fast-binary-scaling-to-determine-the-lo.patch | 116 |
1 files changed, 0 insertions, 116 deletions
diff --git a/debian/patches/0004-libihash-use-fast-binary-scaling-to-determine-the-lo.patch b/debian/patches/0004-libihash-use-fast-binary-scaling-to-determine-the-lo.patch deleted file mode 100644 index 1a835a7f..00000000 --- a/debian/patches/0004-libihash-use-fast-binary-scaling-to-determine-the-lo.patch +++ /dev/null @@ -1,116 +0,0 @@ -From 47ce159fbfca6e14f8ce442573c1fa10365113ff Mon Sep 17 00:00:00 2001 -From: Justus Winter <4winter@informatik.uni-hamburg.de> -Date: Tue, 13 May 2014 18:59:10 +0200 -Subject: [PATCH 04/15] libihash: use fast binary scaling to determine the load - -Expressing the maximum load in binary percent (where 128b% corresponds -to 100%) allows us to use fast binary scaling to determine if the -maximum load has been reached. - -* libihash/ihash.c (hurd_ihash_set_max_load): Update the comment. -(hurd_ihash_add): Use fast binary scaling to determine the current -load. -* libihash/ihash.h (hurd_ihash_set_max_load): Update the comment. ---- - libihash/ihash.c | 37 +++++++++++++++++++++++++++---------- - libihash/ihash.h | 22 ++++++++++++---------- - 2 files changed, 39 insertions(+), 20 deletions(-) - -diff --git a/libihash/ihash.c b/libihash/ihash.c -index d628d75..a4f92d1 100644 ---- a/libihash/ihash.c -+++ b/libihash/ihash.c -@@ -180,14 +180,15 @@ hurd_ihash_set_cleanup (hurd_ihash_t ht, hurd_ihash_cleanup_t cleanup, - } - - --/* Set the maximum load factor in percent to MAX_LOAD, which should be -- between 1 and 100. The default is HURD_IHASH_MAX_LOAD_DEFAULT. -- New elements are only added to the hash table while the number of -- hashed elements is that much percent of the total size of the hash -- table. If more elements are added, the hash table is first -- expanded and reorganized. A MAX_LOAD of 100 will always fill the -- whole table before enlarging it, but note that this will increase -- the cost of operations significantly when the table is almost full. -+/* Set the maximum load factor in binary percent to MAX_LOAD, which -+ should be between 64 and 128. The default is -+ HURD_IHASH_MAX_LOAD_DEFAULT. New elements are only added to the -+ hash table while the number of hashed elements is that much percent -+ of the total size of the hash table. If more elements are added, -+ the hash table is first expanded and reorganized. A MAX_LOAD of -+ 128 will always fill the whole table before enlarging it, but note -+ that this will increase the cost of operations significantly when -+ the table is almost full. - - If the value is set to a smaller value than the current load - factor, the next reorganization will happen when a new item is -@@ -272,8 +273,24 @@ hurd_ihash_add (hurd_ihash_t ht, hurd_ihash_key_t key, hurd_ihash_value_t item) - - if (ht->size) - { -- /* Only fill the hash table up to its maximum load factor. */ -- if ((ht->nr_items * 100) >> __builtin_ctz (ht->size) <= ht->max_load) -+ /* Only fill the hash table up to its maximum load factor given -+ as "binary percent", where 128b% corresponds to 100%. As the -+ size is always a power of two, and 128 is also, the quotient -+ of both is also a power of two. Therefore, we can use bit -+ shifts to scale the number of items. -+ -+ load = nr_items * 128 / size -+ = nr_items^{log2 (128) - log2 (size)} -+ = nr_items >> (log2 (size) - log2 (128)) -+ -- if size >= 128 -+ = nr_items << (log2 (128) - log2 (size)) -+ -- otherwise -+ */ -+ int d = __builtin_ctz (ht->size) - 7; -+ unsigned int load = d >= 0 -+ ? ht->nr_items >> d -+ : ht->nr_items << -d; -+ if (load <= ht->max_load) - if (add_one (ht, key, item)) - return 0; - } -diff --git a/libihash/ihash.h b/libihash/ihash.h -index 8829e51..e245db4 100644 ---- a/libihash/ihash.h -+++ b/libihash/ihash.h -@@ -97,8 +97,9 @@ typedef struct hurd_ihash *hurd_ihash_t; - be a power of two. */ - #define HURD_IHASH_MIN_SIZE 32 - --/* The default value for the maximum load factor in percent. */ --#define HURD_IHASH_MAX_LOAD_DEFAULT 75 -+/* The default value for the maximum load factor in binary percent. -+ 96b% is equivalent to 75%, 128b% to 100%. */ -+#define HURD_IHASH_MAX_LOAD_DEFAULT 96 - - /* The LOCP_OFFS to use if no location pointer is available. */ - #define HURD_IHASH_NO_LOCP INTPTR_MIN -@@ -143,14 +144,15 @@ void hurd_ihash_free (hurd_ihash_t ht); - void hurd_ihash_set_cleanup (hurd_ihash_t ht, hurd_ihash_cleanup_t cleanup, - void *cleanup_data); - --/* Set the maximum load factor in percent to MAX_LOAD, which should be -- between 50 and 100. The default is HURD_IHASH_MAX_LOAD_DEFAULT. -- New elements are only added to the hash table while the number of -- hashed elements is that much percent of the total size of the hash -- table. If more elements are added, the hash table is first -- expanded and reorganized. A MAX_LOAD of 100 will always fill the -- whole table before enlarging it, but note that this will increase -- the cost of operations significantly when the table is almost full. -+/* Set the maximum load factor in binary percent to MAX_LOAD, which -+ should be between 64 and 128. The default is -+ HURD_IHASH_MAX_LOAD_DEFAULT. New elements are only added to the -+ hash table while the number of hashed elements is that much percent -+ of the total size of the hash table. If more elements are added, -+ the hash table is first expanded and reorganized. A MAX_LOAD of -+ 128 will always fill the whole table before enlarging it, but note -+ that this will increase the cost of operations significantly when -+ the table is almost full. - - If the value is set to a smaller value than the current load - factor, the next reorganization will happen when a new item is --- -2.0.0.rc0 - |