From a4aaf906794d9f82710614ba368a36500e8a8254 Mon Sep 17 00:00:00 2001 From: Valentin Bartenev Date: Mon, 22 Oct 2018 16:01:10 +0300 Subject: Re-engineered timers. To optimize rbtree operations, all changes are stored in array and later processed in batches. The previous implementation of this mechanics had a number of design flaws. Each change was saved in a new array entry; until the changes were applied, the timer remained in an intermediate state (NXT_TIMER_CHANGING). This intermediate state didn't allow to identify if time was going to be disabled or enabled. However, the nxt_conn_io_read() function relied on this information; as a result, in some cases the read timeout wasn't set. Also, the nxt_timer_delete() function did not reliably track whether a timer was added to the work queue. It checked the NXT_TIMER_ENQUEUED state of a timer, but this state could be reset to NXT_TIMER_DISABLED by a nxt_timer_disable() call or another nxt_timer_delete() call. Now, instead of keeping the whole history of the timer's changes, the new implementation updates the timer state immediately, and only one operation is added to the array to add or delete timer in the rbtree according to its final state. --- src/nxt_timer.h | 36 +++++++++++++++++++++++------------- 1 file changed, 23 insertions(+), 13 deletions(-) (limited to 'src/nxt_timer.h') diff --git a/src/nxt_timer.h b/src/nxt_timer.h index 6531657d..211564d6 100644 --- a/src/nxt_timer.h +++ b/src/nxt_timer.h @@ -13,20 +13,24 @@ //#define NXT_TIMER_DEFAULT_PRECISION 1 -typedef enum { - NXT_TIMER_DISABLED = 0, - NXT_TIMER_CHANGING, - NXT_TIMER_WAITING, - NXT_TIMER_ENQUEUED, -} nxt_timer_state_t; +/* + * The nxt_timer_t structure can hold up to 14 bits of change index, + * but 0 reserved for NXT_TIMER_NO_CHANGE. + */ +#define NXT_TIMER_MAX_CHANGES 16383 +#define NXT_TIMER_NO_CHANGE 0 typedef struct { /* The rbtree node must be the first field. */ NXT_RBTREE_NODE (node); - nxt_timer_state_t state:8; uint8_t precision; + + uint16_t change:14; + uint16_t enabled:1; + uint16_t queued:1; + nxt_msec_t time; nxt_work_queue_t *work_queue; @@ -37,13 +41,13 @@ typedef struct { } nxt_timer_t; -#define NXT_TIMER { NXT_RBTREE_NODE_INIT, NXT_TIMER_DISABLED, \ - 0, 0, NULL, NULL, NULL, NULL } +#define NXT_TIMER { NXT_RBTREE_NODE_INIT, 0, NXT_TIMER_NO_CHANGE, \ + 0, 0, 0, NULL, NULL, NULL, NULL } typedef enum { - NXT_TIMER_ADD = 0, - NXT_TIMER_DISABLE, + NXT_TIMER_NOPE = 0, + NXT_TIMER_ADD, NXT_TIMER_DELETE, } nxt_timer_operation_t; @@ -94,10 +98,16 @@ void nxt_timer_expire(nxt_event_engine_t *engine, nxt_msec_t now); NXT_EXPORT void nxt_timer_add(nxt_event_engine_t *engine, nxt_timer_t *timer, nxt_msec_t timeout); -NXT_EXPORT void nxt_timer_disable(nxt_event_engine_t *engine, - nxt_timer_t *timer); NXT_EXPORT nxt_bool_t nxt_timer_delete(nxt_event_engine_t *engine, nxt_timer_t *timer); +nxt_inline void +nxt_timer_disable(nxt_event_engine_t *engine, nxt_timer_t *timer) +{ + nxt_debug(timer->task, "timer disable: %M", timer->time); + + timer->enabled = 0; +} + #endif /* _NXT_TIMER_H_INCLUDED_ */ -- cgit From da0ef366dc1affa740618eb4f4baa8bbb62f8d70 Mon Sep 17 00:00:00 2001 From: Valentin Bartenev Date: Mon, 22 Oct 2018 16:04:16 +0300 Subject: Handling of timers with bias. Timers that don't require maximum precision (most of them, actually) can be triggered earlier or later within the bias interval. To reduce wakeups by timers, the expire function now triggers not only all timers that fall within the elapsed time, but also those whose bias falls within this interval. --- src/nxt_timer.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'src/nxt_timer.h') diff --git a/src/nxt_timer.h b/src/nxt_timer.h index 211564d6..4199f0dd 100644 --- a/src/nxt_timer.h +++ b/src/nxt_timer.h @@ -8,9 +8,9 @@ #define _NXT_TIMER_H_INCLUDED_ -/* Valid values are between 1ms to 255ms. */ -#define NXT_TIMER_DEFAULT_PRECISION 100 -//#define NXT_TIMER_DEFAULT_PRECISION 1 +/* Valid values are between 0ms to 255ms. */ +#define NXT_TIMER_DEFAULT_BIAS 50 +//#define NXT_TIMER_DEFAULT_BIAS 0 /* @@ -25,7 +25,7 @@ typedef struct { /* The rbtree node must be the first field. */ NXT_RBTREE_NODE (node); - uint8_t precision; + uint8_t bias; uint16_t change:14; uint16_t enabled:1; -- cgit