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timeout.c
Commit 896a50f1 authored by william's avatar william
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use timeouts_ prefix instead of timer_, which is in the POSIX namespace (they... 

use timeouts_ prefix instead of timer_, which is in the POSIX namespace (they get all the good prefixes!
parent 7d60763b
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Showing with 226 additions and 178 deletions
Makefile
View file @ 896a50f1
......@@ -3,10 +3,26 @@ all: timer
WHEEL_BIT = 6
WHEEL_NUM = 4
CPPFLAGS = -DTIMER_DEBUG -DTIMER_MAIN -DWHEEL_BIT=$(WHEEL_BIT) -DWHEEL_NUM=$(WHEEL_NUM)
CPPFLAGS = -DTIMER_DEBUG -DTIMER_MAIN
CFLAGS = -O2 -g -Wall -Wextra
timer: CPPFLAGS+=-DWHEEL_BIT=$(WHEEL_BIT) -DWHEEL_NUM=$(WHEEL_NUM)
timer8: CPPFLAGS+=-DWHEEL_BIT=3 -DWHEEL_NUM=$(WHEEL_NUM)
timer16: CPPFLAGS+=-DWHEEL_BIT=4 -DWHEEL_NUM=$(WHEEL_NUM)
timer32: CPPFLAGS+=-DWHEEL_BIT=5 -DWHEEL_NUM=$(WHEEL_NUM)
timer64: CPPFLAGS+=-DWHEEL_BIT=6 -DWHEEL_NUM=$(WHEEL_NUM)
timer64 timer32 timer16 timer8 timer: timer.c
$(CC) $(CFLAGS) -o $@ $^ $(CPPFLAGS)
.PHONY: clean clean!
clean:
......
debug.h 0 → 100644
View file @ 896a50f1
/*
* D E B U G R O U T I N E S
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
#if TIMER_DEBUG - 0 || TIMER_MAIN - 0
#include <stdlib.h>
#include <stdio.h>
#undef TIMER_DEBUG
#define TIMER_DEBUG 1
#define DEBUG_LEVEL timer_debug
static int timer_debug;
#define SAYit_(lvl, fmt, ...) do { \
if (DEBUG_LEVEL >= (lvl)) \
fprintf(stderr, fmt "%s", __FILE__, __LINE__, __func__, __VA_ARGS__); \
} while (0)
#define SAYit(lvl, ...) SAYit_((lvl), "%s:%d:%s: " __VA_ARGS__, "\n")
#define PANIC(...) do { \
SAYit(0, __VA_ARGS__); \
_Exit(EXIT_FAILURE); \
} while (0)
#else
#undef TIMER_DEBUG
#define TIMER_DEBUG 0
#define DEBUG_LEVEL 0
#define SAYit(...) (void)0
#endif
#define SAY(...) SAYit(1, __VA_ARGS__)
#define HAI SAY("HAI")
static inline char *fmt_(char *buf, uint64_t ts, int wheel_bit, int wheel_num) {
char *p = buf;
int wheel, n, i;
for (wheel = wheel_num - 2; wheel >= 0; wheel--) {
n = ((1 << wheel_bit) - 1) & (ts >> (wheel * WHEEL_BIT));
for (i = wheel_bit - 1; i >= 0; i--) {
*p++ = '0' + !!(n & (1 << i));
}
if (wheel != 0)
*p++ = ':';
}
*p = 0;
return buf;
} /* fmt_() */
#define fmt(ts) fmt_(((char[((1 << WHEEL_BIT) * WHEEL_NUM) + WHEEL_NUM + 1]){ 0 }), (ts), WHEEL_BIT, WHEEL_NUM)
static inline char *bin64_(char *buf, uint64_t n, int wheel_bit) {
char *p = buf;
int i;
for (i = 0; i < (1 << wheel_bit); i++) {
*p++ = "01"[0x1 & (n >> (((1 << wheel_bit) - 1) - i))];
}
*p = 0;
return buf;
} /* bin64_() */
#define bin64(ts) bin64_(((char[((1 << WHEEL_BIT) * WHEEL_NUM) + 1]){ 0 }), (ts), WHEEL_BIT)
timer.c
View file @ 896a50f1
......@@ -33,83 +33,11 @@
#include <sys/queue.h>
#include "timer.h"
#include "debug.h"
/*
* D E B U G R O U T I N E S
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
#if TIMER_DEBUG - 0 || TIMER_MAIN - 0
#include <stdlib.h>
#include <stdio.h>
#undef TIMER_DEBUG
#define TIMER_DEBUG 1
#define DEBUG_LEVEL timer_debug
static int timer_debug;
#define SAYit_(lvl, fmt, ...) do { \
if (DEBUG_LEVEL >= (lvl)) \
fprintf(stderr, fmt "%s", __FILE__, __LINE__, __func__, __VA_ARGS__); \
} while (0)
#define SAYit(lvl, ...) SAYit_((lvl), "%s:%d:%s: " __VA_ARGS__, "\n")
#define PANIC(...) do { \
SAYit(0, __VA_ARGS__); \
_Exit(EXIT_FAILURE); \
} while (0)
#else
#undef TIMER_DEBUG
#define TIMER_DEBUG 0
#define DEBUG_LEVEL 0
#define SAYit(...) (void)0
#endif
#define SAY(...) SAYit(1, __VA_ARGS__)
#define HAI SAY("HAI")
static inline char *fmt_(char *buf, uint64_t ts, int wheel_bit, int wheel_num) {
char *p = buf;
int wheel, n, i;
for (wheel = wheel_num - 2; wheel >= 0; wheel--) {
n = ((1 << wheel_bit) - 1) & (ts >> (wheel * WHEEL_BIT));
for (i = wheel_bit - 1; i >= 0; i--) {
*p++ = '0' + !!(n & (1 << i));
}
if (wheel != 0)
*p++ = ':';
}
*p = 0;
return buf;
} /* fmt_() */
#define fmt(ts) fmt_(((char[((1 << WHEEL_BIT) * WHEEL_NUM) + WHEEL_NUM + 1]){ 0 }), (ts), WHEEL_BIT, WHEEL_NUM)
static inline char *bin64_(char *buf, uint64_t n, int wheel_bit) {
char *p = buf;
int i;
for (i = 0; i < (1 << wheel_bit); i++) {
*p++ = "01"[0x1 & (n >> (((1 << wheel_bit) - 1) - i))];
}
*p = 0;
return buf;
} /* bin64_() */
#define bin64(ts) bin64_(((char[((1 << WHEEL_BIT) * WHEEL_NUM) + 1]){ 0 }), (ts), WHEEL_BIT)
#define abstime_t timeout_t /* for documentation purposes */
#define reltime_t timeout_t /* "" */
/*
......@@ -117,8 +45,13 @@ static inline char *bin64_(char *buf, uint64_t n, int wheel_bit) {
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
#if !defined countof
#define countof(a) (sizeof (a) / sizeof *(a))
#endif
#if !defined endof
#define endof(a) (&(a)[countof(a)])
#endif
#if !defined MIN
#define MIN(a, b) (((a) < (b))? (a) : (b))
......@@ -151,12 +84,36 @@ static inline char *bin64_(char *buf, uint64_t n, int wheel_bit) {
/*
* B I T M A N I P U L A T I O N R O U T I N E S
*
* These routines implement wheel parameterization.
* The macros and routines below implement wheel parameterization. The
* inputs are:
*
* WHEEL_BIT - The number of value bits mapped in each wheel. The
* lowest-order WHEEL_BIT bits index the lowest-order (highest
* resolution) wheel, the next group of WHEEL_BIT bits the
* higher wheel, etc.
*
* WHEEL_NUM - The number of wheels. WHEEL_BIT * WHEEL_NUM = the number of
* value bits used by all the wheels. For the default of 6 and
* 4, only the low 24 bits are processed. Any timeout value
* larger than this will cycle through again.
*
* The implementation uses bit fields to remember which slot in each wheel
* is populated, and to generate masks of expiring slots according to the
* current update interval (i.e. the "tickless" aspect). The slots to
* process in a wheel are (populated-set & interval-mask).
*
* WHEEL_BIT cannot be larger than 6 bits because 2^6 -> 64 is the largest
* number of slots which can be tracked in a uint64_t integer bit field.
* WHEEL_BIT cannot be smaller than 3 bits because of our rotr and rotl
* routines, which only operate on all the value bits in an integer, and
* there's no integer smaller than uint8_t.
*
* NOTE: Whether our bit-fiddling solution is quicker than looping through
* all the slots is unproven. I hope to do this after this library
* stabilizes.
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
#define TIMER_BIT (sizeof (timer_t) * CHAR_BIT)
#if !defined WHEEL_BIT
#define WHEEL_BIT 6
#endif
......@@ -168,7 +125,7 @@ static inline char *bin64_(char *buf, uint64_t n, int wheel_bit) {
#define WHEEL_LEN (1U << WHEEL_BIT)
#define WHEEL_MAX (WHEEL_LEN - 1)
#define WHEEL_MASK (WHEEL_LEN - 1)
#define TIMEOUT_MAX ((TIMER_C(1) << (WHEEL_BIT * WHEEL_NUM)) - 1)
#define TIMEOUT_MAX ((TIMEOUT_C(1) << (WHEEL_BIT * WHEEL_NUM)) - 1)
#if WHEEL_BIT == 6
......@@ -240,16 +197,16 @@ static inline wheel_t rotr(const wheel_t v, int c) {
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
CIRCLEQ_HEAD(timeouts, timeout);
CIRCLEQ_HEAD(timeout_list, timeout);
#define TIMEOUT_INITIALIZER { 0, 0, { 0, 0 } }
struct timeout {
int flags;
timer_t expires;
timeout_t expires;
struct timeouts *pending;
struct timeout_list *pending;
CIRCLEQ_ENTRY(timeout) cqe;
}; /* struct timeout */
......@@ -268,17 +225,17 @@ struct timeout *timeout_init(struct timeout *to, int flags) {
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
struct timer {
struct timeouts wheel[WHEEL_NUM][WHEEL_LEN], expired;
struct timeouts {
struct timeout_list wheel[WHEEL_NUM][WHEEL_LEN], expired;
wheel_t pending[WHEEL_NUM];
timer_t curtime;
timer_t hertz;
}; /* struct timer */
timeout_t curtime;
timeout_t hertz;
}; /* struct timeouts */
struct timer *timer_init(struct timer *T, timer_t hz) {
static struct timeouts *timeouts_init(struct timeouts *T, timeout_t hz) {
unsigned i, j;
for (i = 0; i < countof(T->wheel); i++) {
......@@ -294,13 +251,13 @@ struct timer *timer_init(struct timer *T, timer_t hz) {
}
T->curtime = 0;
T->hertz = (hz)? hz : TIMER_mHZ;
T->hertz = (hz)? hz : TIMEOUT_mHZ;
return T;
} /* timer_init() */
} /* timeouts_init() */
void timer_del(struct timer *T, struct timeout *to) {
void timeouts_del(struct timeouts *T, struct timeout *to) {
if (to->pending) {
if (to->pending != &T->expired && CIRCLEQ_EMPTY(to->pending)) {
ptrdiff_t index = to->pending - &T->wheel[0][0];
......@@ -313,12 +270,12 @@ void timer_del(struct timer *T, struct timeout *to) {
CIRCLEQ_REMOVE(to->pending, to, cqe);
to->pending = NULL;
}
} /* timer_del() */
} /* timeouts_del() */
static inline timeout_t timer_rem(struct timer *T, struct timeout *to) {
static inline reltime_t timeout_rem(struct timeouts *T, struct timeout *to) {
return to->expires - T->curtime;
} /* timer_rem() */
} /* timeout_rem() */
static inline int timeout_wheel(timeout_t timeout) {
......@@ -326,27 +283,24 @@ static inline int timeout_wheel(timeout_t timeout) {
} /* timeout_wheel() */
static inline int timer_slot(int wheel, timer_t expires) {
static inline int timeout_slot(int wheel, timeout_t expires) {
return WHEEL_MASK & ((expires >> (wheel * WHEEL_BIT)) - !!wheel);
} /* timer_slot() */
} /* timeout_slot() */
void timer_add(struct timer *T, struct timeout *to, timer_t expires) {
void timeouts_add(struct timeouts *T, struct timeout *to, timeout_t expires) {
timeout_t rem;
int wheel, slot;
timer_del(T, to);
timeouts_del(T, to);
to->expires = expires;
if (expires > T->curtime) {
rem = timer_rem(T, to);
rem = timeout_rem(T, to);
wheel = timeout_wheel(rem);
slot = timer_slot(wheel, to->expires);
SAY("%llu rem:%llu wheel:%d (fls:%d) slot:%d", expires, timer_rem(T, to), wheel, fls(timer_rem(T, to)) - 1, slot);
SAY("clock: %s", fmt(expires));
slot = timeout_slot(wheel, to->expires);
to->pending = &T->wheel[wheel][slot];
CIRCLEQ_INSERT_HEAD(to->pending, to, cqe);
......@@ -356,51 +310,49 @@ void timer_add(struct timer *T, struct timeout *to, timer_t expires) {
to->pending = &T->expired;
CIRCLEQ_INSERT_HEAD(to->pending, to, cqe);
}
} /* timer_add() */
} /* timeouts_add() */
void timeout_add(struct timer *T, struct timeout *to, timeout_t timeout) {
timer_add(T, to, T->curtime + timeout);
} /* timeout_add() */
void timer_step(struct timer *T, timer_t curtime) {
void timeouts_step(struct timeouts *T, abstime_t curtime) {
timeout_t elapsed = curtime - T->curtime;
struct timeouts todo;
int wheel, slot;
wheel_t _elapsed;
struct timeout_list todo;
int wheel;
CIRCLEQ_INIT(&todo);
SAYit(2, "\n");
SAYit(2, "== step =========================================");
SAYit(2, "%" TIMER_PRIu " -> %" TIMER_PRIu, T->curtime, curtime);
SAYit(2, "%s -> %s", fmt(T->curtime), fmt(curtime));
/*
* There's no avoiding looping over every wheel. It's best to keep
* WHEEL_NUM smallish.
*/
for (wheel = 0; wheel < WHEEL_NUM; wheel++) {
wheel_t pending;
SAYit(2, "-- wheel (%u) ------------------------------------", wheel);
/*
* Calculate the slots expiring in this wheel
*
* If the elapsed time is greater than the maximum period of
* the wheel, mark every position as expiring.
*
* Otherwise, to determine the expired slots fill in all the
* bits between the last slot processed and the current
* slot, inclusive of the last slot.
*/
if ((elapsed >> (wheel * WHEEL_BIT)) > WHEEL_MAX) {
pending = (wheel_t)~WHEEL_C(0);
} else {
wheel_t _elapsed;
int slot;
_elapsed = WHEEL_MASK & (elapsed >> (wheel * WHEEL_BIT));
slot = WHEEL_MASK & (T->curtime >> (wheel * WHEEL_BIT));
SAYit(2, "wheel:%d _elapsed:%" WHEEL_PRIu " slot:%d", wheel, _elapsed, slot);
pending = rotl(((UINT64_C(1) << _elapsed) - 1), slot);
// slot = WHEEL_MASK & (T->curtime >> (wheel * WHEEL_BIT));
// pending = rotl(((UINT64_C(1) << _elapsed) - 1), slot);
slot = WHEEL_MASK & (curtime >> (wheel * WHEEL_BIT));
SAYit(2, "slot: %d", slot);
pending = rotr(rotl(((WHEEL_C(1) << _elapsed) - 1), slot), _elapsed);
pending |= WHEEL_C(1) << slot;
pending |= rotr(rotl(((WHEEL_C(1) << _elapsed) - 1), slot), _elapsed);
SAYit(2, "rotl:%.*" TIMEOUT_PRIx " pending:%.*" WHEEL_PRIx, (int)(sizeof _elapsed * CHAR_BIT / 4), ((TIMEOUT_C(1) << _elapsed) - 1), (int)(sizeof pending * CHAR_BIT / 4), pending);
}
SAYit(2, "pending : %s", bin64(pending));
SAYit(2, "populated : %s", bin64(T->pending[wheel]));
while (pending & T->pending[wheel]) {
int slot = ctz(pending & T->pending[wheel]);
CIRCLEQ_CONCAT(&todo, &T->wheel[wheel][slot], cqe);
......@@ -422,14 +374,14 @@ void timer_step(struct timer *T, timer_t curtime) {
CIRCLEQ_REMOVE(&todo, to, cqe);
to->pending = 0;
timer_add(T, to, to->expires);
timeouts_add(T, to, to->expires);
}
return;
} /* timer_step() */
} /* timeouts_step() */
bool timer_pending(struct timer *T) {
bool timeouts_pending(struct timeouts *T) {
wheel_t pending = 0;
int wheel;
......@@ -438,12 +390,12 @@ bool timer_pending(struct timer *T) {
}
return !!pending;
} /* timer_pending() */
} /* timeouts_pending() */
timeout_t timer_timeout(struct timer *T) {
timeout_t timeouts_timeout(struct timeouts *T) {
timeout_t timeout = ~TIMEOUT_C(0), _timeout;
timer_t relmask;
timeout_t relmask;
int wheel, slot;
if (!CIRCLEQ_EMPTY(&T->expired))
......@@ -464,16 +416,21 @@ timeout_t timer_timeout(struct timer *T) {
}
return timeout;
} /* timer_timeout() */
} /* timeouts_timeout() */
struct timeout *timer_get(struct timer *T) {
struct timeout *timeouts_get(struct timeouts *T) {
if (!CIRCLEQ_EMPTY(&T->expired)) {
return CIRCLEQ_FIRST(&T->expired);
struct timeout *to = CIRCLEQ_FIRST(&T->expired);
CIRCLEQ_REMOVE(&T->expired, to, cqe);
to->pending = 0;
return to;
} else {
return 0;
}
} /* timer_get() */
} /* timeouts_get() */
#if TIMER_MAIN - 0
......@@ -483,7 +440,7 @@ struct timeout *timer_get(struct timer *T) {
#include <unistd.h>
static timer_t timer_min(struct timer *T) {
static timeout_t timeouts_min(struct timeouts *T) {
struct timeout *to, *min = NULL;
unsigned i, j;
......@@ -497,17 +454,17 @@ static timer_t timer_min(struct timer *T) {
}
return (min)? min->expires : 0;
} /* timer_min() */
} /* timeouts_min() */
static inline timeout_t slow_timeout(struct timer *T) {
return timer_min(T) - T->curtime;
static inline timeout_t slow_timeout(struct timeouts *T) {
return timeouts_min(T) - T->curtime;
} /* slow_timeout() */
int main(int argc, char **argv) {
extern int optind;
extern char *optarg;
struct timer T;
struct timeouts T;
struct timeout to[8];
struct timeout *expired;
uint64_t time = 0, step = 1, stop = 0;
......@@ -541,21 +498,23 @@ int main(int argc, char **argv) {
argc -= optind;
argv += optind;
timer_init(&T, TIMER_mHZ);
timer_step(&T, time);
timer_add(&T, timeout_init(&to[0], 0), time + 62); count++;
timer_add(&T, timeout_init(&to[1], 0), time + 63); count++;
timer_add(&T, timeout_init(&to[2], 0), time + 64); count++;
timer_add(&T, timeout_init(&to[3], 0), time + 65); count++;
timer_add(&T, timeout_init(&to[5], 0), time + 192); count++;
timeouts_init(&T, TIMEOUT_mHZ);
timeouts_step(&T, time);
timeouts_add(&T, timeout_init(&to[0], 0), time + 62); count++;
timeouts_add(&T, timeout_init(&to[1], 0), time + 63); count++;
timeouts_add(&T, timeout_init(&to[2], 0), time + 64); count++;
timeouts_add(&T, timeout_init(&to[3], 0), time + 65); count++;
timeouts_add(&T, timeout_init(&to[5], 0), time + 192); count++;
while (count > 0 && time <= stop - 1) {
time += step;
SAY("timeout -> %" TIMEOUT_PRIu " (actual:%" TIMEOUT_PRIu " curtime:%" TIMER_PRIu ")", timer_timeout(&T), slow_timeout(&T), T.curtime);
timer_step(&T, time);
while ((expired = timer_get(&T))) {
timer_del(&T, expired);
// SAY("timeout -> %" TIMEOUT_PRIu " (actual:%" TIMEOUT_PRIu " curtime:%" TIMEOUT_PRIu ")", timeouts_timeout(&T), slow_timeout(&T), T.curtime);
timeouts_step(&T, time);
while ((expired = timeouts_get(&T))) {
timeouts_del(&T, expired);
SAY("step %llu expired %llu @@@@@@@@@@@@@@@@@@@@", time, expired->expires);
count--;
}
......
timer.h
View file @ 896a50f1
......@@ -35,36 +35,31 @@
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
#define TIMER_mHZ TIMER_C(1000)
#define TIMER_uHZ TIMER_C(1000000)
#define TIMER_nHZ TIMER_C(1000000000)
#define TIMEOUT_C(n) UINT64_C(n)
#define TIMEOUT_PRIu PRIu64
#define TIMEOUT_PRIx PRIx64
#define TIMEOUT_PRIX PRIX64
#define TIMER_C(n) UINT64_C(n)
#define TIMER_PRIu PRIu64
#define TIMER_PRIx PRIx64
#define TIMER_PRIX PRIX64
#define TIMEOUT_mHZ TIMEOUT_C(1000)
#define TIMEOUT_uHZ TIMEOUT_C(1000000)
#define TIMEOUT_nHZ TIMEOUT_C(1000000000)
#define TIMEOUT_C(n) TIMER_C(n)
#define TIMEOUT_PRIu TIMER_PRIu
#define TIMEOUT_PRIx TIMER_PRIx
#define TIMEOUT_PRIX TIMER_PRIX
typedef uint64_t timeout_t;
typedef uint64_t timer_t; /* absolute times */
typedef timer_t timeout_t; /* relative times */
struct timer;
struct timeouts;
struct timeout;
void timer_add(struct timer *, struct timeout *, timeout_t);
void timer_del(struct timer *, struct timeout *);
struct timeouts *timeouts_open(timeout_t);
bool timer_pending(struct timer *);
void timeouts_close(struct timeouts *);
timeout_t timer_timeout(struct timer *);
void timeouts_add(struct timeouts *, struct timeout *, timeout_t);
void timeouts_del(struct timeouts *, struct timeout *);
bool timeouts_pending(struct timeouts *);
timeout_t timeouts_timeout(struct timeouts *);
/*
......@@ -73,13 +68,14 @@ timeout_t timer_timeout(struct timer *);
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
#define TIMEOUT_PERIODIC 0x01
#define TIMEOUT_ABSTIME 0x02
struct timeout *timeout_init(struct timeout *, int);
bool timeout_pending(struct timeout *);
/* true if pending in a timing wheel or on expired queue, false otherwise */
/* true if on timing wheel or expired queue, false otherwise */
bool timeout_expired(struct timeout *);
/* true if currently or previously on expired queue, false otherwise */
/* true if on expired queue, false otherwise */
#endif /* TIMER_H */
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