linux: Move timer fields into a struct

Storing the fields in a struct allows gcc to optimize memory pointers.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
This commit is contained in:
Kevin O'Connor 2021-04-19 08:24:04 -04:00
parent 16b8922af2
commit e0aba590f9
1 changed files with 37 additions and 31 deletions

View File

@ -12,15 +12,24 @@
#include "internal.h" // console_sleep
#include "sched.h" // DECL_INIT
// Global storage for timer handling
static struct {
// Last time reported by timer_read_time()
uint32_t last_read_time;
// Fields for converting from a systime to ticks
time_t start_sec;
// Maximum absolute time that can be spent in timer_dispatch()
uint32_t timer_repeat_until;
// Time of next software timer (also used to convert from ticks to systime)
uint32_t next_wake_counter;
struct timespec next_wake;
} TimerInfo;
/****************************************************************
* Timespec helpers
****************************************************************/
static uint32_t next_wake_time_counter;
static struct timespec next_wake_time;
static time_t start_sec;
// Compare two 'struct timespec' times
static inline uint8_t
timespec_is_before(struct timespec ts1, struct timespec ts2)
@ -33,7 +42,7 @@ timespec_is_before(struct timespec ts1, struct timespec ts2)
static inline uint32_t
timespec_to_time(struct timespec ts)
{
return ((ts.tv_sec - start_sec) * CONFIG_CLOCK_FREQ
return ((ts.tv_sec - TimerInfo.start_sec) * CONFIG_CLOCK_FREQ
+ ts.tv_nsec / NSECS_PER_TICK);
}
@ -41,10 +50,10 @@ timespec_to_time(struct timespec ts)
static inline struct timespec
timespec_from_time(uint32_t time)
{
int32_t counter_diff = time - next_wake_time_counter;
int32_t counter_diff = time - TimerInfo.next_wake_counter;
struct timespec ts;
ts.tv_sec = next_wake_time.tv_sec;
ts.tv_nsec = next_wake_time.tv_nsec + counter_diff * NSECS_PER_TICK;
ts.tv_sec = TimerInfo.next_wake.tv_sec;
ts.tv_nsec = TimerInfo.next_wake.tv_nsec + counter_diff * NSECS_PER_TICK;
if ((unsigned long)ts.tv_nsec >= NSECS) {
if (ts.tv_nsec < 0) {
ts.tv_sec--;
@ -70,9 +79,9 @@ timespec_read(void)
int
timer_check_periodic(struct timespec *ts)
{
if (timespec_is_before(next_wake_time, *ts))
if (timespec_is_before(TimerInfo.next_wake, *ts))
return 0;
*ts = next_wake_time;
*ts = TimerInfo.next_wake;
ts->tv_sec += 2;
return 1;
}
@ -100,14 +109,12 @@ timer_is_before(uint32_t time1, uint32_t time2)
return (int32_t)(time1 - time2) < 0;
}
static uint32_t last_timer_read_time;
// Return the current time (in clock ticks)
uint32_t
timer_read_time(void)
{
uint32_t t = timespec_to_time(timespec_read());
last_timer_read_time = t;
TimerInfo.last_read_time = t;
return t;
}
@ -115,11 +122,10 @@ timer_read_time(void)
void
timer_kick(void)
{
next_wake_time = timespec_read();
next_wake_time_counter = timespec_to_time(next_wake_time);
TimerInfo.next_wake = timespec_read();
TimerInfo.next_wake_counter = timespec_to_time(TimerInfo.next_wake);
}
static uint32_t timer_repeat_until;
#define TIMER_IDLE_REPEAT_TICKS timer_from_us(500)
#define TIMER_REPEAT_TICKS timer_from_us(100)
@ -130,16 +136,16 @@ static uint32_t timer_repeat_until;
static uint32_t
timer_dispatch_many(void)
{
uint32_t tru = timer_repeat_until, prev_ltrt = 0;
uint32_t tru = TimerInfo.timer_repeat_until, prev_lrt = 0;
for (;;) {
// Run the next software timer
uint32_t next = sched_timer_dispatch();
uint32_t ltrt = last_timer_read_time;
if (!timer_is_before(ltrt, next) && !timer_is_before(tru, ltrt)
&& ltrt != prev_ltrt) {
uint32_t lrt = TimerInfo.last_read_time;
if (!timer_is_before(lrt, next) && !timer_is_before(tru, lrt)
&& lrt != prev_lrt) {
// Can run next timer without overhead of calling timer_read_time()
prev_ltrt = ltrt;
prev_lrt = lrt;
continue;
}
@ -154,10 +160,10 @@ timer_dispatch_many(void)
if (diff < (int32_t)(-timer_from_us(100000)))
try_shutdown("Rescheduled timer in the past");
if (sched_tasks_busy()) {
timer_repeat_until = now + TIMER_REPEAT_TICKS;
TimerInfo.timer_repeat_until = now + TIMER_REPEAT_TICKS;
return now + TIMER_DEFER_REPEAT_TICKS;
}
timer_repeat_until = tru = now + TIMER_IDLE_REPEAT_TICKS;
TimerInfo.timer_repeat_until = tru = now + TIMER_IDLE_REPEAT_TICKS;
}
// Next timer in the past or near future - wait for it to be ready
@ -170,10 +176,10 @@ timer_dispatch_many(void)
void
timer_task(void)
{
uint32_t now = last_timer_read_time;
uint32_t lrt = TimerInfo.last_read_time;
irq_disable();
if (timer_is_before(timer_repeat_until, now))
timer_repeat_until = now;
if (timer_is_before(TimerInfo.timer_repeat_until, lrt))
TimerInfo.timer_repeat_until = lrt;
irq_enable();
}
DECL_TASK(timer_task);
@ -183,14 +189,14 @@ static void
timer_dispatch(void)
{
uint32_t next = timer_dispatch_many();
next_wake_time = timespec_from_time(next);
next_wake_time_counter = next;
TimerInfo.next_wake = timespec_from_time(next);
TimerInfo.next_wake_counter = next;
}
void
timer_init(void)
{
start_sec = timespec_read().tv_sec + 1;
TimerInfo.start_sec = timespec_read().tv_sec + 1;
timer_kick();
}
DECL_INIT(timer_init);
@ -224,12 +230,12 @@ irq_restore(irqstatus_t flag)
void
irq_wait(void)
{
console_sleep(next_wake_time);
console_sleep(TimerInfo.next_wake);
}
void
irq_poll(void)
{
if (!timespec_is_before(timespec_read(), next_wake_time))
if (!timespec_is_before(timespec_read(), TimerInfo.next_wake))
timer_dispatch();
}