[Libevent-users] [PATCH] relative timer with EV_PERSIST support +
move event_del logic into event_active + regression tests
Christopher Layne
clayne at anodized.com
Tue Nov 13 21:15:00 EST 2007
1. Make EV_PERSIST reschedule timeouts automatically.
2. New function: timeout_schedule: (nothing really new within it, just
modular wrapping of timeout rescheduling).
3. New macro: evutil_timercpy: tv_dst = tv_src in one line type deal;
3. Regression tests for persistent timeouts, include read/write, signals,
and timers.
4. Another regression test for signal handler restores (no problem, just
added another one).
So what this means is that if you do the following:
event_set(ev, fd, EV_READ | EV_PERSIST, read_cb, obj);
event_add(ev, &timeout);
read_cb() will be called whenever a read event happens, and it's timeout
as passed to event_add() will be reset to the original value you passed.
You do not have to call event_add() within the handler.
event_set(ev, -1, EV_TIMEOUT | EV_PERSIST, timer_cb, obj);
event_add(ev, &cycle);
timer_cb() will be called when timeout (as passed via cycle) expires. It
will then reschedule itself with it's original timeout, e.g. periodic timer.
You do not have to call event_add() within the handler.
For the event_del() changes, it's just moving event_del() into event_active(),
when an event occurs. There is a feature request on sourceforge for this,
and this couples nicely with the EV_PERSIST change. It also allows us to
rexamine the logic tests within the various event dispatchers themselves, as
event_active() will only delete the same event once.
-cl
$ test/regress
Testing Priorities 1: OK
Testing Priorities 2: OK
Testing Priorities 3: OK
Testing Evbuffer: OK
Testing evbuffer_find 1: OK
Testing evbuffer_find 2: OK
Testing evbuffer_find 3: OK
Bufferevent: OK
Free active base: OK
Testing HTTP Server Event Base: OK
Testing HTTP Header filtering: OK
Testing Basic HTTP Server: OK
Testing Request Connection Pipeline : OK
Testing Request Connection Pipeline (persistent): OK
Testing Connection Close Detection: OK
Testing HTTP POST Request: OK
Testing Bad HTTP Request: OK
Testing HTTP Server with high port: OK
Testing HTTP Dispatcher: OK
Testing Basic RPC Support: OK
Testing Good RPC Post: OK
Testing RPC Client: OK
Testing RPC (Queued) Client: OK
Testing RPC Client Timeout: OK
DNS server support: OK
Simple DNS resolve: type: 1, count: 1, ttl: 300: 152.160.49.201 OK
IPv6 DNS resolve: type: 3, count: 1, ttl: 922: 2610:a0:c779:b::d1ad:35b4 OK
Simple read: OK
Simple write: OK
Multiple read/write: OK
Persist read/write: OK
Combined read/write: OK
Simple timeout: OK
Persistent timeout: OK
Persistent read/write timeout: OK
Persistent signal timeout: OK
Simple signal: OK
Immediate signal: OK
Loop exit: OK
Multiple events for same fd: OK
Want read only once: OK
Testing Tagging:
encoded 0x00000af0 with 2 bytes
encoded 0x00001000 with 3 bytes
encoded 0x00000001 with 1 bytes
encoded 0xdeadbeef with 5 bytes
encoded 0x00000000 with 1 bytes
encoded 0x00bef000 with 4 bytes
evtag_int_test: OK
evtag_fuzz: OK
OK
Testing RPC: (1.9 us/add) OK
Signal dealloc: OK
Signal pipeloss: OK
Signal switchbase: OK
Signal handler restore: OK
Signal handler spread restore: OK
Signal handler assert: OK
$ make verify
cd test && make verify
make[1]: Entering directory `/home/clayne/project/libevent.build/test'
Running tests:
KQUEUE
Skipping test
DEVPOLL
Skipping test
POLL
test-eof: OKAY
test-weof: OKAY
test-time: OKAY
regress: type: 1, count: 1, ttl: 300: 152.160.49.201 type: 3, count: 1, ttl: 238: 2610:a0:c779:b::d1ad:35b4 (1.9 us/add) OKAY
SELECT
test-eof: OKAY
test-weof: OKAY
test-time: OKAY
regress: type: 1, count: 1, ttl: 300: 152.160.49.201 type: 3, count: 1, ttl: 1800: 2610:a0:c779:b::d1ad:35b4 (1.9 us/add) OKAY
EPOLL
test-eof: OKAY
test-weof: OKAY
test-time: OKAY
regress: type: 1, count: 1, ttl: 300: 152.160.49.201 type: 3, count: 1, ttl: 1800: 2610:a0:c779:b::d1ad:35b4 (1.8 us/add) OKAY
EVPORT
Skipping test
-------------- next part --------------
Index: event.c
===================================================================
--- event.c (revision 526)
+++ event.c (working copy)
@@ -125,4 +125,6 @@ static int timeout_next(struct event_bas
static void timeout_process(struct event_base *);
static void timeout_correct(struct event_base *, struct timeval *);
+static int timeout_schedule(struct event_base *, struct event *,
+ struct timeval *);
static void
@@ -615,4 +617,5 @@ event_add(struct event *ev, struct timev
const struct eventop *evsel = base->evsel;
void *evbase = base->evbase;
+ min_heap_t *mh = &base->timeheap;
event_debug((
@@ -627,12 +630,4 @@ event_add(struct event *ev, struct timev
if (tv != NULL) {
- struct timeval now;
-
- if (ev->ev_flags & EVLIST_TIMEOUT)
- event_queue_remove(base, ev, EVLIST_TIMEOUT);
- else if (min_heap_reserve(&base->timeheap,
- 1 + min_heap_size(&base->timeheap)) == -1)
- return (-1); /* ENOMEM == errno */
-
/* Check if it is active due to a timeout. Rescheduling
* this timeout before the callback can be executed
@@ -651,12 +646,14 @@ event_add(struct event *ev, struct timev
}
- gettime(&now);
- evutil_timeradd(&now, tv, &ev->ev_timeout);
-
- event_debug((
- "event_add: timeout in %d seconds, call %p",
- tv->tv_sec, ev->ev_callback));
-
- event_queue_insert(base, ev, EVLIST_TIMEOUT);
+ /*
+ * If it's a persistent event, the timeout is considered to
+ * be relative to the last time the event was active. To do
+ * this, store the relative tv in addition to the absolute one.
+ */
+ if (ev->ev_events & EV_PERSIST)
+ evutil_timercpy(&ev->ev_timeout_rel, tv);
+ if (min_heap_reserve(mh, 1 + min_heap_size(mh)) == -1)
+ return (-1); /* ENOMEM == errno */
+ timeout_schedule(base, ev, tv);
}
@@ -727,4 +724,9 @@ event_active(struct event *ev, int res,
return;
}
+ /* Do not delete persistent events. Reschedule timeouts if persist. */
+ if (~ev->ev_events & EV_PERSIST)
+ event_del(ev);
+ else if (ev->ev_flags & EVLIST_TIMEOUT)
+ timeout_schedule(ev->ev_base, ev, &ev->ev_timeout_rel);
ev->ev_res = res;
@@ -734,4 +736,23 @@ event_active(struct event *ev, int res,
}
+int
+timeout_schedule(struct event_base *base, struct event *ev, struct timeval *tv)
+{
+ struct timeval now;
+
+ /* This could probably make use of min_heap_shift_down() somehow */
+ if (ev->ev_flags & EVLIST_TIMEOUT)
+ event_queue_remove(base, ev, EVLIST_TIMEOUT);
+
+ gettime(&now);
+ evutil_timeradd(&now, tv, &ev->ev_timeout);
+ event_queue_insert(base, ev, EVLIST_TIMEOUT);
+
+ event_debug(("%s: %p: timeout in %d seconds, call %p",
+ __func__, ev, tv->tv_sec, ev->ev_callback));
+
+ return (0);
+}
+
static int
timeout_next(struct event_base *base, struct timeval **tv_p)
@@ -818,9 +839,5 @@ timeout_process(struct event_base *base)
break;
- /* delete this event from the I/O queues */
- event_del(ev);
-
- event_debug(("timeout_process: call %p",
- ev->ev_callback));
+ event_debug(("timeout_process: call %p", ev->ev_callback));
event_active(ev, EV_TIMEOUT, 1);
}
Index: event.h
===================================================================
--- event.h (revision 524)
+++ event.h (working copy)
@@ -232,4 +232,5 @@ struct event {
int ev_res; /* result passed to event callback */
int ev_flags;
+ struct timeval ev_timeout_rel; /* relative timeout */
};
Index: evutil.h
===================================================================
--- evutil.h (revision 524)
+++ evutil.h (working copy)
@@ -110,4 +110,10 @@ int evutil_make_socket_nonblocking(int s
#endif
+#define evutil_timercpy(dtv, stv) \
+ do { \
+ (dtv)->tv_sec = (stv)->tv_sec; \
+ (dtv)->tv_usec = (stv)->tv_usec; \
+ } while(0)
+
#ifdef _EVENT_HAVE_STDINT_H
#include <stdint.h>
Index: signal.c
===================================================================
--- signal.c (revision 528)
+++ signal.c (working copy)
@@ -260,6 +260,4 @@ evsignal_process(struct event_base *base
ncalls = base->sig.evsigcaught[EVENT_SIGNAL(ev)];
if (ncalls) {
- if (!(ev->ev_events & EV_PERSIST))
- event_del(ev);
event_active(ev, EV_SIGNAL, ncalls);
base->sig.evsigcaught[EVENT_SIGNAL(ev)] = 0;
Index: epoll.c
===================================================================
--- epoll.c (revision 524)
+++ epoll.c (working copy)
@@ -230,10 +230,4 @@ epoll_dispatch(struct event_base *base,
continue;
- if (evread != NULL && !(evread->ev_events & EV_PERSIST))
- event_del(evread);
- if (evwrite != NULL && evwrite != evread &&
- !(evwrite->ev_events & EV_PERSIST))
- event_del(evwrite);
-
if (evread != NULL)
event_active(evread, EV_READ, 1);
Index: select.c
===================================================================
--- select.c (revision 524)
+++ select.c (working copy)
@@ -195,14 +195,8 @@ select_dispatch(struct event_base *base,
res |= EV_WRITE;
}
- if (r_ev && (res & r_ev->ev_events)) {
- if (!(r_ev->ev_events & EV_PERSIST))
- event_del(r_ev);
+ if (r_ev && (res & r_ev->ev_events))
event_active(r_ev, res & r_ev->ev_events, 1);
- }
- if (w_ev && w_ev != r_ev && (res & w_ev->ev_events)) {
- if (!(w_ev->ev_events & EV_PERSIST))
- event_del(w_ev);
+ if (w_ev && w_ev != r_ev && (res & w_ev->ev_events))
event_active(w_ev, res & w_ev->ev_events, 1);
- }
}
check_selectop(sop);
Index: devpoll.c
===================================================================
--- devpoll.c (revision 524)
+++ devpoll.c (working copy)
@@ -272,10 +272,4 @@ devpoll_dispatch(struct event_base *base
continue;
- if (evread != NULL && !(evread->ev_events & EV_PERSIST))
- event_del(evread);
- if (evwrite != NULL && evwrite != evread &&
- !(evwrite->ev_events & EV_PERSIST))
- event_del(evwrite);
-
if (evread != NULL)
event_active(evread, EV_READ, 1);
Index: poll.c
===================================================================
--- poll.c (revision 524)
+++ poll.c (working copy)
@@ -198,14 +198,8 @@ poll_dispatch(struct event_base *base, v
continue;
- if (r_ev && (res & r_ev->ev_events)) {
- if (!(r_ev->ev_events & EV_PERSIST))
- event_del(r_ev);
+ if (r_ev && (res & r_ev->ev_events))
event_active(r_ev, res & r_ev->ev_events, 1);
- }
- if (w_ev && w_ev != r_ev && (res & w_ev->ev_events)) {
- if (!(w_ev->ev_events & EV_PERSIST))
- event_del(w_ev);
+ if (w_ev && w_ev != r_ev && (res & w_ev->ev_events))
event_active(w_ev, res & w_ev->ev_events, 1);
- }
}
Index: kqueue.c
===================================================================
--- kqueue.c (revision 524)
+++ kqueue.c (working copy)
@@ -275,7 +275,4 @@ kq_dispatch(struct event_base *base, voi
continue;
- if (!(ev->ev_events & EV_PERSIST))
- event_del(ev);
-
event_active(ev, which,
ev->ev_events & EV_SIGNAL ? events[i].data : 1);
Index: test/regress.c
===================================================================
--- test/regress.c (revision 524)
+++ test/regress.c (working copy)
@@ -70,4 +70,5 @@ static int woff;
static int roff;
static int usepersist;
+static int persist_cnt;
static struct timeval tset;
static struct timeval tcalled;
@@ -173,4 +174,100 @@ multiple_read_cb(int fd, short event, vo
void
+persist_write_cb(int fd, short event, void *arg)
+{
+ struct event *ev = arg;
+ ssize_t n;
+
+ test_ok = 0;
+ if (event & EV_TIMEOUT && persist_cnt) {
+ /* Write until done - at which point the read will timeout */
+ if ((n = write(fd, "a", 1)) != -1)
+ return;
+ }
+ event_del(ev);
+
+ return;
+}
+
+void
+persist_read_cb(int fd, short event, void *arg)
+{
+ struct event *ev = arg;
+ char c;
+ ssize_t n;
+
+ test_ok = 0;
+ if (event & EV_TIMEOUT) {
+ /* If timeout has not fired early, we're good. */
+ if (persist_cnt == 0)
+ test_ok = 1;
+ }
+ if (event & EV_READ) {
+ /* With EV_PERSIST, an active event resets the timeout */
+ persist_cnt--;
+ if ((n = read(fd, &c, sizeof c)) != -1)
+ return;
+ }
+ event_del(ev);
+
+ return;
+}
+
+void
+persist_timeout_cb(int fd, short event, void *arg)
+{
+ struct event *ev = arg;
+ (void) fd;
+
+ test_ok = 0;
+ if (event & EV_TIMEOUT) {
+ /* Don't succeed until this cb has repeated persist_cnt times */
+ if (persist_cnt--)
+ return;
+ test_ok = 1;
+ }
+ event_del(ev);
+
+ return;
+}
+
+void
+persist_signal_cb(int fd, short event, void *arg)
+{
+ struct event *ev = arg;
+ (void) fd;
+
+ test_ok = 0;
+ if (event & EV_TIMEOUT && persist_cnt) {
+ raise(SIGUSR1);
+ return;
+ }
+ event_del(ev);
+
+ return;
+}
+
+void
+persist_signal_handler_cb(int fd, short event, void *arg)
+{
+ struct event *ev = arg;
+ (void) fd;
+
+ test_ok = 0;
+ if (event & EV_TIMEOUT) {
+ /* If timeout has not fired early, we're good. */
+ if (persist_cnt == 0)
+ test_ok = 1;
+ }
+ if (event & EV_SIGNAL) {
+ if (persist_cnt--)
+ return;
+ }
+ event_del(ev);
+
+ return;
+}
+
+void
timeout_cb(int fd, short event, void *arg)
{
@@ -446,4 +543,90 @@ test_simpletimeout(void)
}
+void
+test_persistent_timeout(void)
+{
+ struct timeval tv;
+ struct event evt;
+ struct event_base *eb = event_init();
+
+ setup_test("Persistent timeout: ");
+ test_ok = 0;
+ persist_cnt = 8;
+
+ /* Cycle every 250 msec, for persist_cnt cycles */
+ tv.tv_sec = 0;
+ tv.tv_usec = 250000;
+ event_set(&evt, -1, EV_TIMEOUT | EV_PERSIST, persist_timeout_cb, &evt);
+ event_add(&evt, &tv);
+
+ event_dispatch();
+ event_base_free(eb);
+
+ cleanup_test();
+}
+
+void
+test_persistent_timeout_rw(void)
+{
+ struct timeval tv;
+ struct event evw, evr;
+ struct event_base *eb = event_init();
+ int pfd[2];
+
+ setup_test("Persistent read/write timeout: ");
+ test_ok = 0;
+ persist_cnt = 8;
+
+ pipe(pfd);
+ evutil_make_socket_nonblocking(pfd[0]);
+ evutil_make_socket_nonblocking(pfd[1]);
+
+ /* Write every 250 msec, repeated persist_cnt times */
+ tv.tv_sec = 0;
+ tv.tv_usec = 250000;
+ event_set(&evw, pfd[1], EV_TIMEOUT | EV_PERSIST, persist_write_cb, &evw);
+ event_add(&evw, &tv);
+ /* Read until timeout (which will be relative to last active event) */
+ tv.tv_sec = 0;
+ tv.tv_usec = 500000;
+ event_set(&evr, pfd[0], EV_READ | EV_PERSIST, persist_read_cb, &evr);
+ event_add(&evr, &tv);
+
+ event_dispatch();
+ event_base_free(eb);
+
+ close(pfd[1]);
+ close(pfd[0]);
+ cleanup_test();
+}
+
+void
+test_persistent_timeout_signal(void)
+{
+ struct timeval tv;
+ struct event evs, evh;
+ struct event_base *eb = event_init();
+
+ setup_test("Persistent signal timeout: ");
+ test_ok = 0;
+ persist_cnt = 8;
+
+ /* Signal every 250 msec, repeated persist_cnt times */
+ tv.tv_sec = 0;
+ tv.tv_usec = 250000;
+ event_set(&evs, -1, EV_TIMEOUT | EV_PERSIST, persist_signal_cb, &evs);
+ event_add(&evs, &tv);
+ /* Handle until timeout (which will be relative to last active event) */
+ tv.tv_sec = 0;
+ tv.tv_usec = 500000;
+ event_set(&evh, SIGUSR1, EV_SIGNAL | EV_PERSIST, persist_signal_handler_cb, &evh);
+ event_add(&evh, &tv);
+
+ event_dispatch();
+ event_base_free(eb);
+
+ cleanup_test();
+}
+
#ifndef WIN32
void
@@ -454,4 +637,6 @@ test_simplesignal(void)
setup_test("Simple signal: ");
+
+ event_init();
signal_set(&ev, SIGALRM, signal_cb, &ev);
signal_add(&ev, NULL);
@@ -633,4 +818,106 @@ out:
void
+sig_tab_timer_cb(int sig, short event, void *a)
+{
+ raise(sig);
+ return;
+}
+
+void
+sig_tab_dec_cb(int sig, short event, void *a)
+{
+ test_ok--;
+ return;
+}
+
+void
+sig_tab_inc_cb(int sig)
+{
+ test_ok += 2;
+ return;
+}
+
+int sig_tab[] = {
+ SIGABRT,
+ SIGALRM,
+ SIGCHLD,
+ SIGCONT,
+ SIGFPE,
+ SIGHUP,
+ SIGILL,
+ SIGINT,
+ SIGPIPE,
+ SIGQUIT,
+ SIGSEGV,
+ SIGTERM,
+ SIGTSTP,
+ SIGTTIN,
+ SIGTTOU,
+ SIGUSR1,
+ SIGUSR2
+};
+
+/*
+ * assert that we can handle a number of signals and then restore properly.
+ */
+void
+test_signal_spread_restore()
+{
+ struct event *ev, *evt;
+ struct event_base *eb = event_init();
+ struct timeval tv_zero = { 0, 0 };
+#ifdef HAVE_SIGACTION
+ struct sigaction sa;
+#endif
+ size_t i, n = sizeof sig_tab / sizeof *sig_tab;
+
+ printf("Signal handler spread restore: ");
+
+ test_ok = 0;
+ ev = calloc(n, sizeof *ev);
+ evt = calloc(n, sizeof *evt);
+ if (ev == NULL || evt == NULL)
+ goto out;
+ for (i = n; i--; ) {
+ /* standard signal handlers */
+#ifdef HAVE_SIGACTION
+ sa.sa_handler = sig_tab_inc_cb;
+ sa.sa_flags = 0x0;
+ sigemptyset(&sa.sa_mask);
+ if (sigaction(sig_tab[i], &sa, NULL) == -1)
+ goto out;
+#else
+ if (signal(sig_tab[i], sig_tab_inc_cb) == SIG_ERR)
+ goto out;
+#endif
+ /* event handlers */
+ event_set(&ev[i], sig_tab[i], EV_SIGNAL, sig_tab_dec_cb, &ev[i]);
+ event_add(&ev[i], NULL);
+ /* bootstrappers */
+ event_set(&evt[i], sig_tab[i], EV_TIMEOUT, sig_tab_timer_cb, &evt[i]);
+ event_add(&evt[i], &tv_zero);
+ }
+
+ event_dispatch();
+
+ /* at this point test_ok should == -n; */
+ for (i = n; i--; )
+ raise(sig_tab[i]);
+ /* at this point test_ok should == n; */
+
+ /* event handlers decrement, standard signal handlers increment by 2 */
+ if (test_ok == n)
+ test_ok = 1;
+ else
+ test_ok = 0;
+out:
+ event_base_free(eb);
+ free(evt);
+ free(ev);
+ cleanup_test();
+ return;
+}
+
+void
test_free_active_base(void)
{
@@ -1173,4 +1460,7 @@ main (int argc, char **argv)
test_simpletimeout();
+ test_persistent_timeout();
+ test_persistent_timeout_rw();
+ test_persistent_timeout_signal();
#ifndef WIN32
test_simplesignal();
@@ -1192,4 +1482,5 @@ main (int argc, char **argv)
test_signal_switchbase();
test_signal_restore();
+ test_signal_spread_restore();
test_signal_assert();
#endif
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