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Posted to cvs@httpd.apache.org by sf...@apache.org on 2011/02/03 18:02:38 UTC
svn commit: r1066869 - /httpd/httpd/trunk/server/config.c
Author: sf
Date: Thu Feb 3 17:02:38 2011
New Revision: 1066869
URL: http://svn.apache.org/viewvc?rev=1066869&view=rev
Log:
Optimize memory access pattern of ap_merge_per_dir_configs()
According to Linux perf, this is twice as fast as the old loop.
Modified:
httpd/httpd/trunk/server/config.c
Modified: httpd/httpd/trunk/server/config.c
URL: http://svn.apache.org/viewvc/httpd/httpd/trunk/server/config.c?rev=1066869&r1=1066868&r2=1066869&view=diff
==============================================================================
--- httpd/httpd/trunk/server/config.c (original)
+++ httpd/httpd/trunk/server/config.c Thu Feb 3 17:02:38 2011
@@ -210,6 +210,14 @@ typedef int (*handler_func)(request_rec
typedef void *(*dir_maker_func)(apr_pool_t *, char *);
typedef void *(*merger_func)(apr_pool_t *, void *, void *);
+/* A list of the merge_dir_config functions of all loaded modules, sorted
+ * by module_index.
+ * Using this list in ap_merge_per_dir_configs() is faster than following
+ * the module->next linked list because of better memory locality (resulting
+ * in better cache usage).
+ */
+static merger_func *merger_func_cache;
+
/* maximum nesting level for config directories */
#ifndef AP_MAX_INCLUDE_DIR_DEPTH
#define AP_MAX_INCLUDE_DIR_DEPTH (128)
@@ -254,16 +262,14 @@ AP_CORE_DECLARE(ap_conf_vector_t *) ap_m
void **conf_vector = apr_palloc(p, sizeof(void *) * conf_vector_length);
void **base_vector = (void **)base;
void **new_vector = (void **)new_conf;
- module *modp;
-
- for (modp = ap_top_module; modp; modp = modp->next) {
- int i = modp->module_index;
+ int i;
+ for (i = 0; i < total_modules; i++) {
if (!new_vector[i]) {
conf_vector[i] = base_vector[i];
}
else {
- merger_func df = modp->merge_dir_config;
+ const merger_func df = merger_func_cache[i];
if (df && base_vector[i]) {
conf_vector[i] = (*df)(p, base_vector[i], new_vector[i]);
}
@@ -571,6 +577,7 @@ AP_DECLARE(const char *) ap_add_module(m
ap_module_short_names[m->module_index] = strdup(sym_name);
ap_module_short_names[m->module_index][len] = '\0';
+ merger_func_cache[m->module_index] = m->merge_dir_config;
}
@@ -648,6 +655,7 @@ AP_DECLARE(void) ap_remove_module(module
free(ap_module_short_names[m->module_index]);
ap_module_short_names[m->module_index] = NULL;
+ merger_func_cache[m->module_index] = NULL;
m->module_index = -1; /* simulate being unloaded, should
* be unnecessary */
@@ -743,9 +751,12 @@ AP_DECLARE(const char *) ap_setup_prelin
if (!ap_module_short_names)
ap_module_short_names = calloc(sizeof(char *), conf_vector_length);
- if (ap_loaded_modules == NULL || ap_module_short_names == NULL) {
+ if (!merger_func_cache)
+ merger_func_cache = calloc(sizeof(merger_func), conf_vector_length);
+
+ if (ap_loaded_modules == NULL || ap_module_short_names == NULL
+ || merger_func_cache == NULL)
return "Ouch! Out of memory in ap_setup_prelinked_modules()!";
- }
for (m = ap_preloaded_modules, m2 = ap_loaded_modules; *m != NULL; )
*m2++ = *m++;