*** empty log message ***

[software/libev.git] / ev.pod

diff --git a/ev.pod b/ev.pod
index b98a930aa621be1dc30f2e707b662bdfa264e4c7..26d837bab7765a16bfc65778a93d4c0dfd7196a5 100644 (file)
--- a/ev.pod
+++ b/ev.pod
@@ -117,6 +117,12 @@ Returns the current time as libev would use it. Please note that the
 C<ev_now> function is usually faster and also often returns the timestamp
 you actually want to know.
 
 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 ()
 =item int ev_version_major ()
 
 =item int ev_version_minor ()


@@ -319,7 +325,7 @@ but it scales phenomenally better. While poll and select usually scale
 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
 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:
 
 While stopping, setting and starting an I/O watcher in the same iteration
 support for dup:
 
 While stopping, setting and starting an I/O watcher in the same iteration


@@ -571,6 +577,40 @@ Example: For some weird reason, unregister the above signal handler again.
   ev_ref (loop);
   ev_signal_stop (loop, &exitsig);
 
   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 (busy) 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
 
 
 =back
 
 


@@ -951,7 +991,7 @@ This is how one would do it normally anyway, the important point is that
 the libev application should not optimise around libev but should leave
 optimisations to libev.
 
 the libev application should not optimise around libev but should leave
 optimisations to libev.
 

-=head3 Ths special problem of dup'ed file descriptors
+=head3 The special problem of dup'ed file descriptors

 
 Some backends (e.g. epoll), cannot register events for file descriptors,
 but only events for the underlying file descriptions. That menas when you
 
 Some backends (e.g. epoll), cannot register events for file descriptors,
 but only events for the underlying file descriptions. That menas when you


@@ -2299,6 +2339,11 @@ be attempted. This effectively replaces C<gettimeofday> by C<clock_get
 (CLOCK_REALTIME, ...)> and will not normally affect correctness. See the
 note about libraries in the description of C<EV_USE_MONOTONIC>, though.
 
 (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
 =item EV_USE_SELECT
 
 If undefined or defined to be C<1>, libev will compile in support for the