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authorBjörn-Egil Dahlberg <[email protected]>2010-12-07 11:40:52 +0100
committerBjörn-Egil Dahlberg <[email protected]>2010-12-20 16:41:58 +0100
commitce6172a1badb21a97a4235db27e2f991f01d5b0a (patch)
tree8d1eeaedbea12b0609bdd7797b4c2fc12cde820b /erts/emulator
parent059606a330e8e86305699f60de144102560cb57b (diff)
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Teach timer-wheel to keep min time
Increases the speed of the timer-wheel
Diffstat (limited to 'erts/emulator')
-rw-r--r--erts/emulator/beam/time.c47
1 files changed, 44 insertions, 3 deletions
diff --git a/erts/emulator/beam/time.c b/erts/emulator/beam/time.c
index 9cb6ea34ef..a07c746760 100644
--- a/erts/emulator/beam/time.c
+++ b/erts/emulator/beam/time.c
@@ -99,6 +99,8 @@ static erts_smp_mtx_t tiw_lock;
static ErlTimer** tiw; /* the timing wheel, allocated in init_time() */
static Uint tiw_pos; /* current position in wheel */
static Uint tiw_nto; /* number of timeouts in wheel */
+static Uint tiw_min;
+static ErlTimer *tiw_min_ptr;
/* END tiw_lock protected variables */
@@ -182,6 +184,12 @@ static erts_aint_t next_time_internal(void) /* PRE: tiw_lock taken by caller */
if (tiw_nto == 0)
return -1; /* no timeouts in wheel */
+
+ if (tiw_min_ptr) {
+ min = tiw_min;
+ dt = do_time_read();
+ return ((min >= dt) ? (min - dt) : 0);
+ }
/* start going through wheel to find next timeout */
tm = nto = 0;
@@ -194,11 +202,17 @@ static erts_aint_t next_time_internal(void) /* PRE: tiw_lock taken by caller */
if (p->count == 0) {
/* found next timeout */
dt = do_time_read();
+ /* p->count is zero */
+ tiw_min_ptr = p;
+ tiw_min = tm;
return ((tm >= dt) ? (tm - dt) : 0);
} else {
/* keep shortest time in 'min' */
- if (tm + p->count*TIW_SIZE < min)
+ if (tm + p->count*TIW_SIZE < min) {
min = tm + p->count*TIW_SIZE;
+ tiw_min_ptr = p;
+ tiw_min = min;
+ }
}
p = p->next;
}
@@ -252,6 +266,11 @@ static ERTS_INLINE void bump_timer_internal(erts_aint_t dt) /* PRE: tiw_lock is
prev = &tiw[tiw_pos];
while ((p = *prev) != NULL) {
if (p->count < count) { /* we have a timeout */
+ /* remove min time */
+ if (tiw_min_ptr == p) {
+ tiw_min_ptr = NULL;
+ tiw_min = 0;
+ }
*prev = p->next; /* Remove from list */
tiw_nto--;
p->next = NULL;
@@ -270,6 +289,8 @@ static ERTS_INLINE void bump_timer_internal(erts_aint_t dt) /* PRE: tiw_lock is
dtime--;
}
tiw_pos = keep_pos;
+ if (tiw_min_ptr)
+ tiw_min -= dt;
erts_smp_mtx_unlock(&tiw_lock);
@@ -400,6 +421,8 @@ init_time(void)
tiw[i] = NULL;
do_time_init();
tiw_pos = tiw_nto = 0;
+ tiw_min_ptr = NULL;
+ tiw_min = 0;
timer_thread_init();
}
@@ -434,6 +457,18 @@ insert_timer(ErlTimer* p, Uint t)
/* insert at head of list at slot */
p->next = tiw[tm];
tiw[tm] = p;
+
+ /* insert min time */
+ if ((tiw_nto == 0) || ((tiw_min_ptr != NULL) && (ticks < tiw_min))) {
+ tiw_min = ticks;
+ tiw_min_ptr = p;
+ }
+ if ((tiw_min_ptr == p) && (ticks > tiw_min)) {
+ /* some other timer might be 'min' now */
+ tiw_min = 0;
+ tiw_min_ptr = NULL;
+ }
+
tiw_nto++;
timer_thread_post_insert(ticks);
@@ -443,6 +478,7 @@ void
erl_set_timer(ErlTimer* p, ErlTimeoutProc timeout, ErlCancelProc cancel,
void* arg, Uint t)
{
+
erts_deliver_time();
erts_smp_mtx_lock(&tiw_lock);
if (p->active) { /* XXX assert ? */
@@ -476,6 +512,13 @@ erl_cancel_timer(ErlTimer* p)
prev = &tiw[p->slot];
while ((tp = *prev) != NULL) {
if (tp == p) {
+
+ /* is it the 'min' timer ? */
+ if (p == tiw_min_ptr) {
+ tiw_min_ptr = NULL;
+ tiw_min = 0;
+ }
+
*prev = p->next; /* Remove from list */
tiw_nto--;
p->next = NULL;
@@ -530,7 +573,6 @@ time_left(ErlTimer *p)
}
#ifdef DEBUG
-
void p_slpq()
{
int i;
@@ -560,5 +602,4 @@ void p_slpq()
erts_smp_mtx_unlock(&tiw_lock);
}
-
#endif /* DEBUG */