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Update.

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2000-06-13  Kaz Kylheku  <kaz@ashi.footprints.net>

	A few optimizations.  Got rid of unnecessary wakeups of timer threads,
	tightened up some critical regions and micro-optimized some list
	manipulation code.

	* sysdeps/pthread/timer_routines.c (__timer_thread_queue_timer):
	Returns int value now to indicate whether timer was queued at head.
	* sysdeps/pthread/posix-timer.h: Likewise.
	* sysdeps/pthread/timer_settime.c (timer_settime): Takes advantage of
	new return value from __timer_thread_queue_timer to avoid waking
	up timer thread unnecessarily.

	* sysdeps/pthread/posix-timer.h (timer_id2ptr): No longer checks
	inuse flag, because this requires mutex to be held.  Callers updated
	to do the check when they have the mutex.
	* sysdeps/pthread/timer_getoverr.c: Add check for inuse here.

	* sysdeps/pthread/timer_settime.c (timer_settime): Tighter critical
	regions: avoids making system calls while holding timer mutex, and
	a few computations were moved outside of the mutex as well.
	* sysdeps/pthread/timer_gettime.c (timer_gettime): Likewise.

	* sysdeps/pthread/posix-timer.h (list_unlink_ip): Function name changed
	to list_unlink_ip, meaning idempotent.  Pointer manipulation
	changed to get better better code out of gcc.
	* sysdeps/pthread/timer_routines.c (list_unlink): Non-idempotent
	version of list_unlink added here.
	* sysdeps/pthread/timer_delete.c: Use appropriate list unlink
	function in all places: idempotent one for timers, non-idempotent
	one for thread nodes.
	* sysdeps/pthread/timer_settime: Likewise.
	* sysdeps/pthread/timer_routines.c: Likewise.
This commit is contained in:
Ulrich Drepper 2000-06-14 06:13:45 +00:00
parent 1bfae4012a
commit 38161ac76e
7 changed files with 116 additions and 36 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

34
linuxthreads/ChangeLog
View File

@ -1,3 +1,37 @@
2000-06-13 Kaz Kylheku <kaz@ashi.footprints.net>
A few optimizations. Got rid of unnecessary wakeups of timer threads,
tightened up some critical regions and micro-optimized some list
manipulation code.
* sysdeps/pthread/timer_routines.c (__timer_thread_queue_timer):
Returns int value now to indicate whether timer was queued at head.
* sysdeps/pthread/posix-timer.h: Likewise.
* sysdeps/pthread/timer_settime.c (timer_settime): Takes advantage of
new return value from __timer_thread_queue_timer to avoid waking
up timer thread unnecessarily.
* sysdeps/pthread/posix-timer.h (timer_id2ptr): No longer checks
inuse flag, because this requires mutex to be held. Callers updated
to do the check when they have the mutex.
* sysdeps/pthread/timer_getoverr.c: Add check for inuse here.
* sysdeps/pthread/timer_settime.c (timer_settime): Tighter critical
regions: avoids making system calls while holding timer mutex, and
a few computations were moved outside of the mutex as well.
* sysdeps/pthread/timer_gettime.c (timer_gettime): Likewise.
* sysdeps/pthread/posix-timer.h (list_unlink_ip): Function name changed
to list_unlink_ip, meaning idempotent. Pointer manipulation
changed to get better better code out of gcc.
* sysdeps/pthread/timer_routines.c (list_unlink): Non-idempotent
version of list_unlink added here.
* sysdeps/pthread/timer_delete.c: Use appropriate list unlink
function in all places: idempotent one for timers, non-idempotent
one for thread nodes.
* sysdeps/pthread/timer_settime: Likewise.
* sysdeps/pthread/timer_routines.c: Likewise.
2000-06-13 Ulrich Drepper <drepper@redhat.com>
* sysdeps/unix/sysv/linux/bits/posix_opt.h (_POSIX_TIMERS): Define.

17
linuxthreads/sysdeps/pthread/posix-timer.h
View File

@ -93,7 +93,7 @@ extern struct thread_node __timer_signal_thread_tclk;
static inline struct timer_node *
timer_id2ptr (timer_t timerid)
{
if (timerid >= 0 && timerid < TIMER_MAX && __timer_array[timerid].inuse)
if (timerid >= 0 && timerid < TIMER_MAX)
return &__timer_array[timerid];
return NULL;
@ -155,10 +155,17 @@ timespec_sub (struct timespec *diff, const struct timespec *left,
/* We need one of the list functions in the other modules. */
static inline void
list_unlink (struct list_links *list)
list_unlink_ip (struct list_links *list)
{
list->next->prev = list->prev;
list->prev->next = list->next;
struct list_links *lnext = list->next, *lprev = list->prev;
lnext->prev = lprev;
lprev->next = lnext;
/* The suffix ip means idempotent; list_unlink_ip can be called
* two or more times on the same node.
*/
list->next = list;
list->prev = list;
}
@ -173,6 +180,6 @@ extern struct thread_node *__timer_thread_find_matching (const pthread_attr_t *d
extern struct thread_node *__timer_thread_alloc (const pthread_attr_t *desired_attr, clockid_t);
extern void __timer_dealloc (struct timer_node *timer);
extern void __timer_thread_dealloc (struct thread_node *thread);
extern void __timer_thread_queue_timer (struct thread_node *thread,
extern int __timer_thread_queue_timer (struct thread_node *thread,
struct timer_node *insert);
extern void __timer_thread_wakeup (struct thread_node *thread);

4
linuxthreads/sysdeps/pthread/timer_delete.c
View File

@ -36,7 +36,7 @@ timer_delete (timerid)
pthread_mutex_lock (&__timer_mutex);
timer = timer_id2ptr (timerid);
if (timer == NULL)
if (timer == NULL || !timer->inuse)
/* Invalid timer ID or the timer is not in use. */
errno = EINVAL;
else
@ -58,7 +58,7 @@ timer_delete (timerid)
}
/* Remove timer from whatever queue it may be on and deallocate it. */
list_unlink (&timer->links);
list_unlink_ip (&timer->links);
__timer_dealloc (timer);
retval = 0;
}

7
linuxthreads/sysdeps/pthread/timer_getoverr.c
View File

@ -29,16 +29,15 @@ int
timer_getoverrun (timerid)
timer_t timerid;
{
struct timer_node *timer;
int retval = -1;
pthread_mutex_lock (&__timer_mutex);
if (timer_id2ptr (timerid) == NULL)
if ((timer = timer_id2ptr (timerid)) == NULL || !timer->inuse)
errno = EINVAL;
else
{
retval = 0; /* TODO: overrun counting not supported */
}
retval = 0; /* TODO: overrun counting not supported */
pthread_mutex_lock (&__timer_mutex);

4
linuxthreads/sysdeps/pthread/timer_gettime.c
View File

@ -37,7 +37,7 @@ timer_gettime (timerid, value)
pthread_mutex_lock (&__timer_mutex);
timer = timer_id2ptr (timerid);
if (timer == NULL)
if (timer == NULL && !timer->inuse)
/* Invalid timer ID or the timer is not in use. */
errno = EINVAL;
else
@ -46,7 +46,9 @@ timer_gettime (timerid, value)
if (timer->armed)
{
pthread_mutex_unlock (&__timer_mutex);
clock_gettime (timer->clock, &now);
pthread_mutex_lock (&__timer_mutex);
timespec_sub (&value->it_value, &timer->expirytime, &now);
}
else

31
linuxthreads/sysdeps/pthread/timer_routines.c
View File

@ -90,6 +90,20 @@ list_insbefore (struct list_links *list, struct list_links *newp)
list_append (list, newp);
}
/*
* Like list_unlink_ip, except that calling it on a node that
* is already unlinked is disastrous rather than a noop.
*/
static inline void
list_unlink (struct list_links *list)
{
struct list_links *lnext = list->next, *lprev = list->prev;
lnext->prev = lprev;
lprev->next = lnext;
}
static inline struct list_links *
list_first (struct list_links *list)
{
@ -279,10 +293,7 @@ thread_cleanup (void *val)
thread->current_timer = 0;
if (list_isempty (&thread->timer_queue))
{
list_unlink (&thread->links);
__timer_thread_dealloc (thread);
}
else
(void) __timer_thread_start (thread);
@ -394,7 +405,7 @@ thread_func (void *arg)
if (timespec_compare (&now, &timer->expirytime) < 0)
break;
list_unlink (first);
list_unlink_ip (first);
if (__builtin_expect (timer->value.it_interval.tv_sec, 0) != 0
|| timer->value.it_interval.tv_nsec != 0)
@ -432,12 +443,16 @@ thread_func (void *arg)
}
/* Enqueue a timer in wakeup order in the thread's timer queue. */
void
/* Enqueue a timer in wakeup order in the thread's timer queue.
Returns 1 if the timer was inserted at the head of the queue,
causing the queue's next wakeup time to change. */
int
__timer_thread_queue_timer (struct thread_node *thread,
struct timer_node *insert)
{
struct list_links *iter;
int athead = 1;
for (iter = list_first (&thread->timer_queue);
iter != list_null (&thread->timer_queue);
@ -447,9 +462,11 @@ __timer_thread_queue_timer (struct thread_node *thread,
if (timespec_compare (&insert->expirytime, &timer->expirytime) < 0)
break;
athead = 0;
}
list_insbefore (iter, &insert->links);
return athead;
}
@ -533,7 +550,7 @@ __timer_alloc (void)
if (node != list_null (&timer_free_list))
{
struct timer_node *timer = timer_links2ptr (node);
list_unlink (node);
list_unlink_ip (node);
timer->inuse = 1;
return timer;
}

55
linuxthreads/sysdeps/pthread/timer_settime.c
View File

@ -35,11 +35,9 @@ timer_settime (timerid, flags, value, ovalue)
struct timer_node *timer;
struct thread_node *thread = NULL;
struct timespec now;
int have_now = 0;
int have_now = 0, need_wakeup = 0;
int retval = -1;
pthread_mutex_lock (&__timer_mutex);
timer = timer_id2ptr (timerid);
if (timer == NULL)
{
@ -56,14 +54,40 @@ timer_settime (timerid, flags, value, ovalue)
goto bail;
}
/* Will need to know current time since this is a relative timer;
might as well make the system call outside of the lock now! */
if ((flags & TIMER_ABSTIME) == 0)
{
clock_gettime (timer->clock, &now);
have_now = 1;
}
pthread_mutex_lock (&__timer_mutex);
/* One final check of timer validity; this one is possible only
until we have the mutex, which guards the inuse flag. */
if (!timer->inuse)
{
errno = EINVAL;
goto unlock_bail;
}
if (ovalue != NULL)
{
ovalue->it_interval = timer->value.it_interval;
if (timer->armed)
{
clock_gettime (timer->clock, &now);
have_now = 1;
if (! have_now)
{
pthread_mutex_unlock (&__timer_mutex);
clock_gettime (timer->clock, &now);
have_now = 1;
pthread_mutex_lock (&__timer_mutex);
}
timespec_sub (&ovalue->it_value, &timer->expirytime, &now);
}
else
@ -75,11 +99,12 @@ timer_settime (timerid, flags, value, ovalue)
timer->value = *value;
list_unlink (&timer->links);
list_unlink_ip (&timer->links);
timer->armed = 0;
thread = timer->thread;
/* A value of { 0, 0 } causes the timer to be stopped. */
if (value->it_value.tv_sec != 0
|| __builtin_expect (value->it_value.tv_nsec != 0, 1))
{
@ -87,25 +112,21 @@ timer_settime (timerid, flags, value, ovalue)
/* The user specified the expiration time. */
timer->expirytime = value->it_value;
else
{
if (! have_now)
clock_gettime (timer->clock, &now);
timespec_add (&timer->expirytime, &now, &value->it_value);
timespec_add (&timer->expirytime, &now, &value->it_value);
}
__timer_thread_queue_timer (thread, timer);
/* Only need to wake up the thread if timer is inserted
at the head of the queue. */
need_wakeup = __timer_thread_queue_timer (thread, timer);
timer->armed = 1;
}
retval = 0;
bail:
unlock_bail:
pthread_mutex_unlock (&__timer_mutex);
/* TODO: optimize this. Only need to wake up the thread if inserting
a new timer at the head of the queue. */
if (thread != NULL)
bail:
if (thread != NULL && need_wakeup)
__timer_thread_wakeup (thread);
return retval;