Libevent's current timeout code is relatively optimized for the
randomly scattered timeout case, where events are added with their
timeouts in no particular order. We add and remove timeouts with
O(lg n) behavior.
Frequently, however, an application will want to have many timeouts
of the same value. For example, we might have 1000 bufferevents,
each with a 2 second timeout on reading or writing. If we knew this
were always the case, we could just put timeouts in a queue and get
O(1) add and remove behavior. Of course, a queue would give O(n)
performance for a scattered timeout pattern, so we don't want to
just switch the implementation.
This patch gives the user the ability to explicitly tag certain
timeout values as being "very common". These timeout values have a
cookie encoded in the high bits of their tv_usec field to indicate
which queue they belong on. The queues themselves are each
triggered by an entry in the minheap.
See the regress_main.c code for an example use.
svn:r1517
I've gone through everything that it declared to see where it was used,
and it seems that we probably don't need it anywhere.
Here's what it declared, and why I think we're okay dropping it.
o struct timeval {}
(Used all over, and we can't really get away with declaring it ourselves;
we need the same definition the system uses. If we can't find struct
timeval, we're pretty much sunk.)
o struct timespec {}
(Used in event.c, evdns.c, kqueue.c, evport.c. Of these,
kqueue.c and event.c include sys/_time.h. event.c conditions its use on
_EVENT_HAVE_CLOCK_GETTIME, and kqueue() only works if timespec is defined.)
o TIMEVAL_TO_TIMESPEC
(Used in kqueue.c, but every place with kqueue has sys/time.h)
o struct timezone {}
(event2/util.h has a forward declaration; only evutil.c references it and
doesn't look at its contents.)
o timerclear, timerisset, timercmp, timeradd, timersub
(Everything now uses the evutil_timer* variants.)
o ITIMER_REAL, ITIMER_VIRTUAL, ITIMER_PROF, struct itemerval
(These are only used in test/regress.c, which does not include _time.h)
o CLOCK_REALTIME
(Only used in evdns.c, which does not include _time.h)
o TIMESPEC_TO_TIMEVAL
o DST_*
o timespecclear, timespecisset, timespeccmp, timespecadd, timespecsub
o struct clockinfo {}
o CLOCK_VIRTUAL, CLOCK_PROF
o TIMER_RELTIME, TIMER_ABSTIME
(unused)
svn:r1494
This is a glass-box test to get more coverage on the event loop
backends. We've run into bugs here before with fencepost errors, and
it turns out that none of our unit tests had enough events to
exercise the resize code.
Most of the backends have some kind of logic that resizes an array
when:
- The highest fd is too high
- The number of events added since the last iteration of the loop
is too high
- The number of active events is too high.
This test hits all 3 cases, and increases coverage in select.c by 7%,
in poll by 1%, and in kqueue by 9%.
svn:r1482
Previously, each of the three make-an-event-base functions would exit
under different, weird circumstances, but return NULL on others.
- All three would exit on OOM sometimes.
- event_base_new() and event_init() would die if all backends were
disabled.
- None of them would die if the socketpair() call failed.
Now, only event_init() exits on failure, and it exits on every kind of
failure. event_base_new() and event_base_new_with_config() never do.
svn:r1472
Basically, we suppress the notification when an event is added or deleted
and:
- The event has no fd, or there is no change in whether we are
reading/writing on the event's fd.
- The event has no timeout, or adding the event did not make the earliest
timeout become earlier.
This should be a big efficiency win in applications with multiple threads and
lots of timeouts.
svn:r1439
The problem was introduced when we changed the semantics of
get_supported_methods() to reflect all the methods that exist.
Previously, it had not returned methods disabled from the environment,
but the test didn't know that.
svn:r1379
They're now called evtag_encode_int(64). The old names are available
as macros in event2/tag_compat.h.
Also, add unit tests for encode/decode_int64.
svn:r1365
The big win here is that we can get process-level isolation.
This has been tested to work okay on at least Linux and Win32. Only
the tests in regress.c have been converted wrapped in the new wrapper
functions; the others are still on the old system.
svn:r1073
a) this is 2009
b) niels and nick have been comaintainers for a while
c) saying "all rights reserved" when you then go on to explicitly
disclaim some rights is sheer cargo-cultism.
svn:r1065
