Changeset 2893

Timestamp:

Sep 8, 2016, 6:14:46 AM (9 years ago)

Author:

bird

Message:

variables.c/target_environment: Cache the exported variables in the global_variable_set since there are likely to be very very many of them and they aren't usually changing when we've loaded the makefiles and start running make jobs. Also, use smaller hash tables for collecting exported variables (I've bumped VARIABLE_BUCKETS up a lot).

File:

• trunk/src/kmk/variable.c (modified) (10 diffs)

trunk/src/kmk/variable.c

@@ -59 +59 @@
 #endif
 
+#ifdef KMK
+/* Incremented every time a variable is modified, so that target_environment
+   knows when to regenerate the table of exported global variables.  */
+static size_t global_variable_generation = 0;
+#endif
+
 
 /* Chain of all pattern-specific variables.  */
@@ -217 +223 @@
 #define SMALL_SCOPE_VARIABLE_BUCKETS    13
 # endif
+#endif
+#ifndef ENVIRONMENT_VARIABLE_BUCKETS    /* added by bird. */
+# define ENVIRONMENT_VARIABLE_BUCKETS   256
 #endif
 
@@ -271 +280 @@
   struct variable **var_slot;
   struct variable var_key;
+
+#ifdef KMK
+  if (set == NULL || set == &global_variable_set)
+    global_variable_generation++;
+#endif
 
   if (env_overrides && origin == o_env)
@@ -518 +532 @@
   var_slot = (struct variable **) hash_find_slot_strcached (&set->table, &var_key);
 #endif
+#ifdef KMK
+  if (set == &global_variable_set)
+    global_variable_generation++;
+#endif
 
   if (env_overrides && origin == o_env)
@@ -566 +584 @@
   struct variable     *v;
   struct variable     **var_slot;
+
+#ifdef KMK
+  if (set == NULL || set == &global_variable_set)
+    global_variable_generation++;
+#endif
 
   /* Look it up the hash table slot for it. */
@@ -1970 +1993 @@
 int export_all_variables;
 
+#ifdef KMK
+/* Cached table containing the exports of the global_variable_set.  When
+   there are many global variables, it can be so expensive to construct the
+   child environment that we have a majority of job slot idle.  */
+static size_t             global_variable_set_exports_generation = ~(size_t)0;
+static struct hash_table  global_variable_set_exports;
+
+static void update_global_variable_set_exports(void)
+{
+  struct variable **v_slot;
+  struct variable **v_end;
+
+  /* Re-initialize the table. */
+  if (global_variable_set_exports_generation != ~(size_t)0)
+    hash_free (&global_variable_set_exports, 0);
+  hash_init_strcached (&global_variable_set_exports, ENVIRONMENT_VARIABLE_BUCKETS,
+                       &variable_strcache, offsetof (struct variable, name));
+
+  /* do pretty much the same as target_environment. */
+  v_slot = (struct variable **) global_variable_set.table.ht_vec;
+  v_end = v_slot + global_variable_set.table.ht_size;
+  for ( ; v_slot < v_end; v_slot++)
+    if (! HASH_VACANT (*v_slot))
+      {
+        struct variable **new_slot;
+        struct variable *v = *v_slot;
+
+        switch (v->export)
+          {
+          case v_default:
+            if (v->origin == o_default || v->origin == o_automatic)
+              /* Only export default variables by explicit request.  */
+              continue;
+
+            /* The variable doesn't have a name that can be exported.  */
+            if (! v->exportable)
+              continue;
+
+            if (! export_all_variables
+                && v->origin != o_command
+                && v->origin != o_env && v->origin != o_env_override)
+              continue;
+            break;
+
+          case v_export:
+            break;
+
+          case v_noexport:
+            {
+              /* If this is the SHELL variable and it's not exported,
+                 then add the value from our original environment, if
+                 the original environment defined a value for SHELL.  */
+              extern struct variable shell_var;
+              if (streq (v->name, "SHELL") && shell_var.value)
+                {
+                  v = &shell_var;
+                  break;
+                }
+              continue;
+            }
+
+          case v_ifset:
+            if (v->origin == o_default)
+              continue;
+            break;
+          }
+
+        assert (strcache2_is_cached (&variable_strcache, v->name));
+        new_slot = (struct variable **) hash_find_slot_strcached (&global_variable_set_exports, v);
+        if (HASH_VACANT (*new_slot))
+          hash_insert_at (&global_variable_set_exports, v, new_slot);
+      }
+
+  /* done */
+  global_variable_set_exports_generation = global_variable_generation;
+}
+
+#endif
+
 /* Create a new environment for FILE's commands.
    If FILE is nil, this is for the `shell' function.
@@ -1989 +2091 @@
 #endif
 
+#ifdef KMK
+  if (global_variable_set_exports_generation != global_variable_generation)
+    update_global_variable_set_exports();
+#endif
+
   if (file == 0)
     set_list = current_variable_set_list;
@@ -1995 +2102 @@
 
 #ifndef CONFIG_WITH_STRCACHE2
-  hash_init (&table, VARIABLE_BUCKETS,
+  hash_init (&table, ENVIRONMENT_VARIABLE_BUCKETS,
              variable_hash_1, variable_hash_2, variable_hash_cmp);
 #else  /* CONFIG_WITH_STRCACHE2 */
-  hash_init_strcached (&table, VARIABLE_BUCKETS,
+  hash_init_strcached (&table, ENVIRONMENT_VARIABLE_BUCKETS,
                        &variable_strcache, offsetof (struct variable, name));
 #endif /* CONFIG_WITH_STRCACHE2 */
@@ -2007 +2114 @@
     {
       struct variable_set *set = s->set;
+#ifdef KMK
+      if (set == &global_variable_set)
+        {
+          assert(s->next == NULL);
+          break;
+        }
+#endif
       v_slot = (struct variable **) set->table.ht_vec;
       v_end = v_slot + set->table.ht_size;
@@ -2084 +2198 @@
           }
     }
+
+#ifdef KMK
+  /* Add the global exports to table. */
+  v_slot = (struct variable **) global_variable_set_exports.ht_vec;
+  v_end = v_slot + global_variable_set_exports.ht_size;
+  for ( ; v_slot < v_end; v_slot++)
+    if (! HASH_VACANT (*v_slot))
+      {
+        struct variable **new_slot;
+        struct variable *v = *v_slot;
+        assert (strcache2_is_cached (&variable_strcache, v->name));
+        new_slot = (struct variable **) hash_find_slot_strcached (&table, v);
+        if (HASH_VACANT (*new_slot))
+          hash_insert_at (&table, v, new_slot);
+      }
+#endif
 
 #ifndef CONFIG_WITH_STRCACHE2