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Optimize: Use an array-list instead of a linked-list of keywords.

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Storing list elements in contiguous memory means: less cache misses.
This reduces the execution time of gperf on large inputs by ca. 30%.

* src/arraylist.h: New file.
* src/arraylist.cc: New file.
* src/Makefile.in (OBJECTS): Add arraylist.$(OBJEXT).
(ARRAYLIST_H): New variable.
(arraylist.$(OBJEXT)): New rule.
(search.$(OBJEXT)): Update dependencies.
(SOURCE_FILES): Add arraylist.cc and arraylist.h.
* src/search.cc: Include arraylist.h.
(struct EquivalenceClass): An an ArrayList field. Remove the linked-list
fields. Add a constructor.
(Search::compute_partition, delete_partition): Update.
(Search::count_possible_collisions, Search::unchanged_partition,
Search::find_asso_values): Update.
This commit is contained in:
Bruno Haible
2025-04-19 15:56:43 +02:00
parent a69b7c1c81
commit b1ff3c70b1
5 changed files with 267 additions and 28 deletions
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45
src/search.cc
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@@ -32,6 +32,7 @@
#include "gl_map.hh"
#include "gl_hash_map.h"
#include "options.h"
#include "arraylist.h"
#include "hash-table.h"
/* ============================== Portability ============================== */
@@ -948,12 +949,12 @@ Search::prepare_asso_values ()
struct EquivalenceClass
{
/* The keywords in this equivalence class. */
KeywordExt_List * _keywords;
KeywordExt_List * _keywords_last;
/* The number of keywords in this equivalence class. */
unsigned int _cardinality;
ArrayList<KeywordExt*> _keywords;
EquivalenceClass * _next;
/* Constructor. */
EquivalenceClass () : _keywords () {}
};
struct Step
@@ -1046,9 +1047,6 @@ Search::compute_partition (bool *undetermined) const
if (equclass == NULL)
{
equclass = new EquivalenceClass();
equclass->_keywords = NULL;
equclass->_keywords_last = NULL;
equclass->_cardinality = 0;
equclass->_next = NULL;
/* Map this keyword (and all equivalent ones that will be seen later)
@@ -1063,13 +1061,7 @@ Search::compute_partition (bool *undetermined) const
}
/* Add the keyword to the equivalence class. */
KeywordExt_List *cons = new KeywordExt_List(keyword);
if (equclass->_keywords)
equclass->_keywords_last->rest() = cons;
else
equclass->_keywords = cons;
equclass->_keywords_last = cons;
equclass->_cardinality++;
equclass->_keywords.add_last (keyword);
}
return partition;
@@ -1082,7 +1074,6 @@ delete_partition (EquivalenceClass *partition)
{
EquivalenceClass *equclass = partition;
partition = equclass->_next;
delete_list (equclass->_keywords);
delete equclass;
}
}
@@ -1104,9 +1095,10 @@ Search::count_possible_collisions (EquivalenceClass *partition, unsigned int c)
for (unsigned int i = 0; i <= m; i++)
split_cardinalities[i] = 0;
for (KeywordExt_List *temp = cls->_keywords; temp; temp = temp->rest())
size_t cls_size = cls->_keywords.size();
for (size_t index = 0; index < cls_size; index++)
{
KeywordExt *keyword = temp->first();
KeywordExt *keyword = cls->_keywords.get_at(index);
unsigned int count = 0;
for (int i = 0; i < keyword->_selchars_length; i++)
@@ -1116,7 +1108,7 @@ Search::count_possible_collisions (EquivalenceClass *partition, unsigned int c)
split_cardinalities[count]++;
}
sum += cls->_cardinality * cls->_cardinality;
sum += cls->_keywords.size() * cls->_keywords.size();
for (unsigned int i = 0; i <= m; i++)
sum -= split_cardinalities[i] * split_cardinalities[i];
}
@@ -1133,16 +1125,17 @@ Search::unchanged_partition (EquivalenceClass *partition, unsigned int c) const
{
unsigned int first_count = UINT_MAX;
for (KeywordExt_List *temp = cls->_keywords; temp; temp = temp->rest())
size_t cls_size = cls->_keywords.size();
for (size_t index = 0; index < cls_size; index++)
{
KeywordExt *keyword = temp->first();
KeywordExt *keyword = cls->_keywords.get_at(index);
unsigned int count = 0;
for (int i = 0; i < keyword->_selchars_length; i++)
if (keyword->_selchars[i] == c)
count++;
if (temp == cls->_keywords)
if (index == 0)
first_count = count;
else if (count != first_count)
/* c would split this equivalence class. */
@@ -1295,9 +1288,10 @@ Search::find_asso_values ()
for (EquivalenceClass *cls = step->_partition; cls; cls = cls->_next)
{
fprintf (stderr, "\n");
for (KeywordExt_List *temp = cls->_keywords; temp; temp = temp->rest())
size_t cls_size = cls->_keywords.size();
for (size_t index = 0; index < cls_size; index++)
{
KeywordExt *keyword = temp->first();
KeywordExt *keyword = cls->_keywords.get_at(index);
fprintf (stderr, " %.*s\n",
keyword->_allchars_length, keyword->_allchars);
}
@@ -1347,9 +1341,10 @@ Search::find_asso_values ()
/* Iteration Number array is a win, O(1) initialization time! */
_collision_detector->clear ();
for (KeywordExt_List *ptr = cls->_keywords; ptr; ptr = ptr->rest())
size_t cls_size = cls->_keywords.size();
for (size_t index = 0; index < cls_size; index++)
{
KeywordExt *keyword = ptr->first();
KeywordExt *keyword = cls->_keywords.get_at(index);
/* Compute the new hash code for the keyword, leaving apart
the yet undetermined asso_values[]. */