From 74d4b6625d3660d106d8a785befaa7457b6fe288 Mon Sep 17 00:00:00 2001 From: Stefan Fritsch Date: Thu, 3 Feb 2011 17:02:38 +0000 Subject: Optimize memory access pattern of ap_merge_per_dir_configs() According to Linux perf, this is twice as fast as the old loop. git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1066869 13f79535-47bb-0310-9956-ffa450edef68 --- server/config.c | 25 ++++++++++++++++++------- 1 file changed, 18 insertions(+), 7 deletions(-) (limited to 'server/config.c') diff --git a/server/config.c b/server/config.c index 00f51c8af7..dc776a2653 100644 --- a/server/config.c +++ b/server/config.c @@ -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_merge_per_dir_configs(apr_pool_t *p, 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(module *m, apr_pool_t *p, 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 *m) 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_prelinked_modules(process_rec *process) 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++; -- cgit v1.2.1