timer: put level-0 optimization directly into find_first.
authorRusty Russell <rusty@rustcorp.com.au>
Tue, 19 May 2015 20:51:43 +0000 (06:21 +0930)
committerRusty Russell <rusty@rustcorp.com.au>
Tue, 19 May 2015 20:51:43 +0000 (06:21 +0930)
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
ccan/timer/timer.c

index 4e0b7101cc0df6a8c4ce7a75bfbc4e5b71e86ba5..208d8e6988f1a2d8871ecf40aecb64b8f7f4e282 100644 (file)
@@ -131,7 +131,10 @@ static void add_level(struct timers *timers, unsigned int level)
                timer_add_raw(timers, t);
 }
 
+/* We don't need to search past the first at level 0, since the
+ * bucket range is 1; they're all the same. */
 static const struct timer *find_first(const struct list_head *list,
+                                     unsigned int level,
                                      const struct timer *prev)
 {
        struct timer *t;
@@ -139,6 +142,8 @@ static const struct timer *find_first(const struct list_head *list,
        list_for_each(list, t, list) {
                if (!prev || t->time < prev->time)
                        prev = t;
+               if (level == 0)
+                       break;
        }
        return prev;
 }
@@ -162,7 +167,7 @@ static const struct timer *get_first(const struct timers *timers)
 
 next:
        if (!timers->level[level])
-               return find_first(&timers->far, NULL);
+               return find_first(&timers->far, -1U, NULL);
 
        need_next = false;
        off = base % PER_LEVEL;
@@ -188,15 +193,12 @@ next:
        }
 
        /* Level 0 is exact, so they're all the same. */
-       if (level == 0)
-               found = list_top(h, struct timer, list);
-       else
-               found = find_first(h, NULL);
+       found = find_first(h, level, NULL);
 
        while (need_next) {
                need_next = false;
                if (!timers->level[level+1]) {
-                       found = find_first(&timers->far, found);
+                       found = find_first(&timers->far, -1U, found);
                } else {
                        /* Current upper bucket has emptied into this
                         * bucket; we want *next* one. */
@@ -208,7 +210,7 @@ next:
                                need_next = true;
                        } else {
                                h = &timers->level[level+1]->list[off];
-                               found = find_first(h, found);
+                               found = find_first(h, level+1, found);
                        }
                }
        }