new huge patch series

1 files changed, 116 insertions, 0 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
new file mode 100644
index 00000000..1a835a7f
--- /dev/null
+++ b/debian/patches/0004-libihash-use-fast-binary-scaling-to-determine-the-lo.patch
@@ -0,0 +1,116 @@
+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
+