ev_recommended_backends
ev_ref
ev_set_allocator
+ev_set_io_collect_interval
ev_set_syserr_cb
+ev_set_timeout_collect_interval
ev_signal_start
ev_signal_stop
+ev_sleep
ev_stat_start
ev_stat_stat
ev_stat_stop
.\" ========================================================================
.\"
.IX Title "EV 1"
-.TH EV 1 "2007-12-21" "perl v5.8.8" "User Contributed Perl Documentation"
+.TH EV 1 "2007-12-22" "perl v5.8.8" "User Contributed Perl Documentation"
.SH "NAME"
libev \- a high performance full\-featured event loop written in C
.SH "SYNOPSIS"
Returns the current time as libev would use it. Please note that the
\&\f(CW\*(C`ev_now\*(C'\fR function is usually faster and also often returns the timestamp
you actually want to know.
+.IP "void ev_sleep (ev_tstamp interval)" 4
+.IX Item "void ev_sleep (ev_tstamp interval)"
+Sleep for the given interval: The current thread will be blocked until
+either it is interrupted or the given time interval has passed. Basically
+this is a subsecond-resolution \f(CW\*(C`sleep ()\*(C'\fR.
.IP "int ev_version_major ()" 4
.IX Item "int ev_version_major ()"
.PD 0
like O(total_fds) where n is the total number of fds (or the highest fd),
epoll scales either O(1) or O(active_fds). The epoll design has a number
of shortcomings, such as silently dropping events in some hard-to-detect
-cases and rewuiring a syscall per fd change, no fork support and bad
+cases and rewiring a syscall per fd change, no fork support and bad
support for dup:
.Sp
While stopping, setting and starting an I/O watcher in the same iteration
\& ev_ref (loop);
\& ev_signal_stop (loop, &exitsig);
.Ve
+.IP "ev_set_io_collect_interval (ev_tstamp interval)" 4
+.IX Item "ev_set_io_collect_interval (ev_tstamp interval)"
+.PD 0
+.IP "ev_set_timeout_collect_interval (ev_tstamp interval)" 4
+.IX Item "ev_set_timeout_collect_interval (ev_tstamp interval)"
+.PD
+These advanced functions influence the time that libev will spend waiting
+for events. Both are by default \f(CW0\fR, meaning that libev will try to
+invoke timer/periodic callbacks and I/O callbacks with minimum latency.
+.Sp
+Setting these to a higher value (the \f(CW\*(C`interval\*(C'\fR \fImust\fR be >= \f(CW0\fR)
+allows libev to delay invocation of I/O and timer/periodic callbacks to
+increase efficiency of loop iterations.
+.Sp
+The background is that sometimes your program runs just fast enough to
+handle one (or very few) event(s) per loop iteration. While this makes
+the program responsive, it also wastes a lot of \s-1CPU\s0 time to poll for new
+events, especially with backends like \f(CW\*(C`select ()\*(C'\fR which have a high
+overhead for the actual polling but can deliver many events at once.
+.Sp
+By setting a higher \fIio collect interval\fR you allow libev to spend more
+time collecting I/O events, so you can handle more events per iteration,
+at the cost of increasing latency. Timeouts (both \f(CW\*(C`ev_periodic\*(C'\fR and
+\&\f(CW\*(C`ev_timer\*(C'\fR) will be not affected.
+.Sp
+Likewise, by setting a higher \fItimeout collect interval\fR you allow libev
+to spend more time collecting timeouts, at the expense of increased
+latency (the watcher callback will be called later). \f(CW\*(C`ev_io\*(C'\fR watchers
+will not be affected.
+.Sp
+Many programs can usually benefit by setting the io collect interval to
+a value near \f(CW0.1\fR or so, which is often enough for interactive servers
+(of course not for games), likewise for timeouts. It usually doesn't make
+much sense to set it to a lower value than \f(CW0.01\fR, as this approsaches
+the timing granularity of most systems.
.SH "ANATOMY OF A WATCHER"
.IX Header "ANATOMY OF A WATCHER"
A watcher is a structure that you create and register to record your
be attempted. This effectively replaces \f(CW\*(C`gettimeofday\*(C'\fR by \f(CW\*(C`clock_get
(CLOCK_REALTIME, ...)\*(C'\fR and will not normally affect correctness. See the
note about libraries in the description of \f(CW\*(C`EV_USE_MONOTONIC\*(C'\fR, though.
+.IP "\s-1EV_USE_NANOSLEEP\s0" 4
+.IX Item "EV_USE_NANOSLEEP"
+If defined to be \f(CW1\fR, libev will assume that \f(CW\*(C`nanosleep ()\*(C'\fR is available
+and will use it for delays. Otherwise it will use \f(CW\*(C`select ()\*(C'\fR.
.IP "\s-1EV_USE_SELECT\s0" 4
.IX Item "EV_USE_SELECT"
If undefined or defined to be \f(CW1\fR, libev will compile in support for the
# endif
# endif
+# ifndef EV_USE_NANOSLEEP
+# if HAVE_NANOSLEEP
+# define EV_USE_NANOSLEEP 1
+# else
+# define EV_USE_NANOSLEEP 0
+# endif
+# endif
+
# ifndef EV_USE_SELECT
# if HAVE_SELECT && HAVE_SYS_SELECT_H
# define EV_USE_SELECT 1
# define EV_USE_REALTIME 0
#endif
+#ifndef EV_USE_NANOSLEEP
+# define EV_USE_NANOSLEEP 0
+#endif
+
#ifndef EV_USE_SELECT
# define EV_USE_SELECT 1
#endif
# define EV_USE_INOTIFY 0
#endif
+#if !EV_USE_NANOSLEEP
+# ifndef _WIN32
+# include <sys/select.h>
+# endif
+#endif
+
#if EV_USE_INOTIFY
# include <sys/inotify.h>
#endif
}
#endif
+void
+ev_sleep (ev_tstamp delay)
+{
+ if (delay > 0.)
+ {
+#if EV_USE_NANOSLEEP
+ struct timespec ts;
+
+ ts.tv_sec = (time_t)delay;
+ ts.tv_nsec = (long)((delay - (ev_tstamp)(ts.tv_sec)) * 1e9);
+
+ nanosleep (&ts, 0);
+#elif defined(_WIN32)
+ Sleep (delay * 1e3);
+#else
+ struct timeval tv;
+
+ tv.tv_sec = (time_t)delay;
+ tv.tv_usec = (long)((delay - (ev_tstamp)(tv.tv_sec)) * 1e6);
+
+ select (0, 0, 0, 0, &tv);
+#endif
+ }
+}
+
+/*****************************************************************************/
+
int inline_size
array_nextsize (int elem, int cur, int cnt)
{
return loop_count;
}
+void
+ev_set_io_collect_interval (EV_P_ ev_tstamp interval)
+{
+ io_blocktime = interval;
+}
+
+void
+ev_set_timeout_collect_interval (EV_P_ ev_tstamp interval)
+{
+ timeout_blocktime = interval;
+}
+
static void noinline
loop_init (EV_P_ unsigned int flags)
{
now_floor = mn_now;
rtmn_diff = ev_rt_now - mn_now;
+ io_blocktime = 0.;
+ timeout_blocktime = 0.;
+
/* pid check not overridable via env */
#ifndef _WIN32
if (flags & EVFLAG_FORKCHECK)
/* calculate blocking time */
{
- ev_tstamp block;
+ ev_tstamp waittime = 0.;
+ ev_tstamp sleeptime = 0.;
- if (expect_false (flags & EVLOOP_NONBLOCK || idleall || !activecnt))
- block = 0.; /* do not block at all */
- else
+ if (expect_true (!(flags & EVLOOP_NONBLOCK || idleall || !activecnt)))
{
/* update time to cancel out callback processing overhead */
time_update (EV_A_ 1e100);
- block = MAX_BLOCKTIME;
+ waittime = MAX_BLOCKTIME;
if (timercnt)
{
ev_tstamp to = ((WT)timers [0])->at - mn_now + backend_fudge;
- if (block > to) block = to;
+ if (waittime > to) waittime = to;
}
#if EV_PERIODIC_ENABLE
if (periodiccnt)
{
ev_tstamp to = ((WT)periodics [0])->at - ev_rt_now + backend_fudge;
- if (block > to) block = to;
+ if (waittime > to) waittime = to;
}
#endif
- if (expect_false (block < 0.)) block = 0.;
+ if (expect_false (waittime < timeout_blocktime))
+ waittime = timeout_blocktime;
+
+ sleeptime = waittime - backend_fudge;
+
+ if (expect_true (sleeptime > io_blocktime))
+ sleeptime = io_blocktime;
+
+ if (sleeptime)
+ {
+ ev_sleep (sleeptime);
+ waittime -= sleeptime;
+ }
}
++loop_count;
- backend_poll (EV_A_ block);
+ backend_poll (EV_A_ waittime);
/* update ev_rt_now, do magic */
- time_update (EV_A_ block);
+ time_update (EV_A_ waittime + sleeptime);
}
/* queue pending timers and reschedule them */
unsigned int ev_embeddable_backends (void);
ev_tstamp ev_time (void);
+void ev_sleep (ev_tstamp delay); /* sleep for a while */
/* Sets the allocation function to use, works like realloc.
* It is used to allocate and free memory.
/* you can actually call it at any time, anywhere :) */
void ev_default_fork (void);
-unsigned int ev_backend (EV_P);
-unsigned int ev_loop_count (EV_P);
+unsigned int ev_backend (EV_P); /* backend in use by loop */
+unsigned int ev_loop_count (EV_P); /* number of loop iterations */
#endif
#define EVLOOP_NONBLOCK 1 /* do not block/wait */
void ev_loop (EV_P_ int flags);
void ev_unloop (EV_P_ int how); /* set to 1 to break out of event loop, set to 2 to break out of all event loops */
+void ev_set_io_collect_interval (EV_P_ ev_tstamp interval); /* sleep at least this time, default 0 */
+void ev_set_timeout_collect_interval (EV_P_ ev_tstamp interval); /* sleep at least this time, default 0 */
+
/*
* ref/unref can be used to add or remove a refcount on the mainloop. every watcher
* keeps one reference. if you have a long-runing watcher you never unregister that
C<ev_now> function is usually faster and also often returns the timestamp
you actually want to know.
+=item ev_sleep (ev_tstamp interval)
+
+Sleep for the given interval: The current thread will be blocked until
+either it is interrupted or the given time interval has passed. Basically
+this is a subsecond-resolution C<sleep ()>.
+
=item int ev_version_major ()
=item int ev_version_minor ()
ev_ref (loop);
ev_signal_stop (loop, &exitsig);
+=item ev_set_io_collect_interval (loop, ev_tstamp interval)
+
+=item ev_set_timeout_collect_interval (loop, ev_tstamp interval)
+
+These advanced functions influence the time that libev will spend waiting
+for events. Both are by default C<0>, meaning that libev will try to
+invoke timer/periodic callbacks and I/O callbacks with minimum latency.
+
+Setting these to a higher value (the C<interval> I<must> be >= C<0>)
+allows libev to delay invocation of I/O and timer/periodic callbacks to
+increase efficiency of loop iterations.
+
+The background is that sometimes your program runs just fast enough to
+handle one (or very few) event(s) per loop iteration. While this makes
+the program responsive, it also wastes a lot of CPU time to poll for new
+events, especially with backends like C<select ()> which have a high
+overhead for the actual polling but can deliver many events at once.
+
+By setting a higher I<io collect interval> you allow libev to spend more
+time collecting I/O events, so you can handle more events per iteration,
+at the cost of increasing latency. Timeouts (both C<ev_periodic> and
+C<ev_timer>) will be not affected.
+
+Likewise, by setting a higher I<timeout collect interval> you allow libev
+to spend more time collecting timeouts, at the expense of increased
+latency (the watcher callback will be called later). C<ev_io> watchers
+will not be affected.
+
+Many programs can usually benefit by setting the io collect interval to
+a value near C<0.1> or so, which is often enough for interactive servers
+(of course not for games), likewise for timeouts. It usually doesn't make
+much sense to set it to a lower value than C<0.01>, as this approsaches
+the timing granularity of most systems.
+
=back
(CLOCK_REALTIME, ...)> and will not normally affect correctness. See the
note about libraries in the description of C<EV_USE_MONOTONIC>, though.
+=item EV_USE_NANOSLEEP
+
+If defined to be C<1>, libev will assume that C<nanosleep ()> is available
+and will use it for delays. Otherwise it will use C<select ()>.
+
=item EV_USE_SELECT
If undefined or defined to be C<1>, libev will compile in support for the
VARx(ev_tstamp, now_floor) /* last time we refreshed rt_time */
VARx(ev_tstamp, mn_now) /* monotonic clock "now" */
VARx(ev_tstamp, rtmn_diff) /* difference realtime - monotonic time */
+
+VARx(ev_tstamp, io_blocktime);
+VARx(ev_tstamp, timeout_blocktime);
+
VARx(int, backend)
VARx(int, activecnt) /* total number of active events ("refcount") */
VARx(unsigned int, loop_count); /* total number of loop iterations/blocks */
+VARx(int, backend_fd)
VARx(ev_tstamp, backend_fudge) /* assumed typical timer resolution */
VAR (backend_modify, void (*backend_modify)(EV_P_ int fd, int oev, int nev))
VAR (backend_poll , void (*backend_poll)(EV_P_ ev_tstamp timeout))
-VARx(int, backend_fd)
#if !defined(_WIN32) || EV_GENWRAP
VARx(pid_t, curpid)
#define now_floor ((loop)->now_floor)
#define mn_now ((loop)->mn_now)
#define rtmn_diff ((loop)->rtmn_diff)
+#define io_blocktime ((loop)->io_blocktime)
+#define timeout_blocktime ((loop)->timeout_blocktime)
#define backend ((loop)->backend)
#define activecnt ((loop)->activecnt)
#define loop_count ((loop)->loop_count)
+#define backend_fd ((loop)->backend_fd)
#define backend_fudge ((loop)->backend_fudge)
#define backend_modify ((loop)->backend_modify)
#define backend_poll ((loop)->backend_poll)
-#define backend_fd ((loop)->backend_fd)
#define curpid ((loop)->curpid)
#define postfork ((loop)->postfork)
#define vec_ri ((loop)->vec_ri)
#undef now_floor
#undef mn_now
#undef rtmn_diff
+#undef io_blocktime
+#undef timeout_blocktime
#undef backend
#undef activecnt
#undef loop_count
+#undef backend_fd
#undef backend_fudge
#undef backend_modify
#undef backend_poll
-#undef backend_fd
#undef curpid
#undef postfork
#undef vec_ri
fi
])
+AC_CHECK_FUNC(nanonsleep, [], [
+ if test -z "$LIBEV_M4_AVOID_LIBRT"; then
+ AC_CHECK_LIB(rt, nanonsleep)
+ unset ac_cv_func_nanonsleep
+ AC_CHECK_FUNCS(nanonsleep)
+ fi
+])
+
AC_CHECK_LIB(m, ceil)
projects / software / libev.git / commitdiff