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authorRickard Green <[email protected]>2016-08-31 14:29:56 +0200
committerRickard Green <[email protected]>2016-08-31 14:29:56 +0200
commit74fecb1c89c9f3149dc0e42b2a4a19827a28370f (patch)
tree878cc36923f6fd7cee7d5cc8475021610a5617e3
parentbfe6427fa5ec615e73fc0aad2c5760370d786b19 (diff)
parent451eb69edbe6c1b2ed53bcac18babda57e5f964c (diff)
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Merge branch 'maint'
* maint: Improve accuracy of timeouts using premature timeouts
-rw-r--r--erts/emulator/sys/common/erl_poll.c14
-rw-r--r--erts/include/internal/erl_misc_utils.h29
-rw-r--r--erts/lib_src/pthread/ethr_event.c74
3 files changed, 98 insertions, 19 deletions
diff --git a/erts/emulator/sys/common/erl_poll.c b/erts/emulator/sys/common/erl_poll.c
index e394d84f73..b8a28bcc18 100644
--- a/erts/emulator/sys/common/erl_poll.c
+++ b/erts/emulator/sys/common/erl_poll.c
@@ -75,6 +75,7 @@
#include "erl_driver.h"
#include "erl_alloc.h"
#include "erl_msacc.h"
+#include "erl_misc_utils.h"
#if !defined(ERTS_POLL_USE_EPOLL) \
&& !defined(ERTS_POLL_USE_DEVPOLL) \
@@ -2132,16 +2133,19 @@ get_timeout(ErtsPollSet ps,
if (timeout > (ErtsMonotonicTime) INT_MAX)
timeout = (ErtsMonotonicTime) INT_MAX;
save_timeout_time += ERTS_MSEC_TO_MONOTONIC(timeout);
+ timeout -= ERTS_PREMATURE_TIMEOUT(timeout, 1000);
break;
case 1000000:
/* Round up to nearest even micro second */
timeout = ERTS_MONOTONIC_TO_USEC(diff_time - 1) + 1;
save_timeout_time += ERTS_USEC_TO_MONOTONIC(timeout);
+ timeout -= ERTS_PREMATURE_TIMEOUT(timeout, 1000*1000);
break;
case 1000000000:
/* Round up to nearest even nano second */
timeout = ERTS_MONOTONIC_TO_NSEC(diff_time - 1) + 1;
save_timeout_time += ERTS_NSEC_TO_MONOTONIC(timeout);
+ timeout -= ERTS_PREMATURE_TIMEOUT(timeout, 1000*1000*1000);
break;
default:
ERTS_INTERNAL_ERROR("Invalid resolution");
@@ -2452,7 +2456,15 @@ ERTS_POLL_EXPORT(erts_poll_wait)(ErtsPollSet ps,
}
#endif
- res = check_fd_events(ps, to, no_fds);
+ while (1) {
+ res = check_fd_events(ps, to, no_fds);
+ if (res != 0)
+ break;
+ if (to == ERTS_POLL_NO_TIMEOUT)
+ break;
+ if (erts_get_monotonic_time(NULL) >= timeout_time)
+ break;
+ }
woke_up(ps);
diff --git a/erts/include/internal/erl_misc_utils.h b/erts/include/internal/erl_misc_utils.h
index a4a5d1d510..55566ddf74 100644
--- a/erts/include/internal/erl_misc_utils.h
+++ b/erts/include/internal/erl_misc_utils.h
@@ -56,4 +56,33 @@ int erts_map_win_error_to_errno(DWORD win_error);
int erts_get_last_win_errno(void);
#endif
+#if defined(__APPLE__) && defined(__MACH__) && !defined(__DARWIN__)
+#define __DARWIN__ 1
+#endif
+
+/*
+ * ERTS_PREMATURE_TIMEOUT() expects time units
+ * 1000 (millisec), 1000000 (microsec), or
+ * 1000000000 (nanosec). Might not work properly
+ * otherwise.
+ */
+#undef ERTS_USE_PREMATURE_TIMEOUT
+#undef ERTS_PREMATURE_TIMEOUT
+
+#if defined(__DARWIN__)
+#define ERTS_USE_PREMATURE_TIMEOUT 1
+#define ERTS_PREMATURE_TIMEOUT(TMO, TU) \
+ ((TMO) >= 1 * ((TU) / 1000) \
+ ? ((TMO) >= 20 * ((TU) / 1000) \
+ ? 15 * ((TU) / 1000) \
+ : ((TMO) >= 5 * ((TU) / 1000) \
+ ? 3 * ((TU) / 1000) \
+ : 5 * ((TU) / 10000))) \
+ : 0)
+
+#else
+#define ERTS_USE_PREMATURE_TIMEOUT 0
+#define ERTS_PREMATURE_TIMEOUT(TMO, TU) (0)
+#endif
+
#endif /* #ifndef ERL_MISC_UTILS_H_ */
diff --git a/erts/lib_src/pthread/ethr_event.c b/erts/lib_src/pthread/ethr_event.c
index eef88d5002..464875570a 100644
--- a/erts/lib_src/pthread/ethr_event.c
+++ b/erts/lib_src/pthread/ethr_event.c
@@ -184,6 +184,8 @@ return_event_on:
#include <errno.h>
#include <string.h>
+#include "erl_misc_utils.h"
+
#ifdef __DARWIN__
struct ethr_event_fdsets___ {
@@ -346,12 +348,9 @@ wait__(ethr_event *e, int spincount, ethr_sint64_t timeout)
ethr_sint32_t val;
int res, ulres;
int until_yield = ETHR_YIELD_AFTER_BUSY_LOOPS;
- ethr_sint64_t time = 0; /* SHUT UP annoying faulty warning... */
+ ethr_sint64_t time = 0;
#ifdef ETHR_HAVE_ETHR_GET_MONOTONIC_TIME
- ethr_sint64_t start = 0; /* SHUT UP annoying faulty warning... */
-#endif
-#ifdef ETHR_HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC
- struct timespec cond_timeout;
+ ethr_sint64_t timeout_time = 0; /* SHUT UP annoying faulty warning... */
#endif
val = ethr_atomic32_read(&e->state);
@@ -365,30 +364,27 @@ wait__(ethr_event *e, int spincount, ethr_sint64_t timeout)
if (timeout == 0)
return ETIMEDOUT;
else {
- time = timeout;
- switch (e->fd[0]) {
- case ETHR_EVENT_INVALID_FD__:
#ifdef ETHR_HAVE_ETHR_GET_MONOTONIC_TIME
- start = ethr_get_monotonic_time();
+ timeout_time = ethr_get_monotonic_time();
+ timeout_time += timeout;
#endif
+ switch (e->fd[0]) {
+ case ETHR_EVENT_INVALID_FD__:
+ time = timeout;
setup_nonblocking_pipe(e);
break;
#ifdef ETHR_HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC
case ETHR_EVENT_COND_TIMEDWAIT__:
- time += ethr_get_monotonic_time();
- cond_timeout.tv_sec = time / (1000*1000*1000);
- cond_timeout.tv_nsec = time % (1000*1000*1000);
+ time = -1;
if (spincount == 0)
goto set_event_off_waiter;
break;
#endif
default:
+ time = timeout;
/* Already initialized pipe... */
if (spincount == 0)
goto set_select_timeout;
-#ifdef ETHR_HAVE_ETHR_GET_MONOTONIC_TIME
- start = ethr_get_monotonic_time();
-#endif
break;
}
}
@@ -418,6 +414,9 @@ wait__(ethr_event *e, int spincount, ethr_sint64_t timeout)
|| e->fd[0] == ETHR_EVENT_COND_TIMEDWAIT__
#endif
) {
+#ifdef ETHR_HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC
+ struct timespec cond_timeout;
+#endif
set_event_off_waiter:
@@ -446,9 +445,35 @@ wait__(ethr_event *e, int spincount, ethr_sint64_t timeout)
#ifdef ETHR_HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC
if (timeout > 0) {
+ if (time != timeout_time) {
+ time = timeout_time;
+
+#if ERTS_USE_PREMATURE_TIMEOUT
+ {
+ ethr_sint64_t rtmo;
+
+ rtmo = timeout_time - ethr_get_monotonic_time();
+ if (rtmo <= 0) {
+ res = ETIMEDOUT;
+ break;
+ }
+ time = timeout_time;
+ time -= ERTS_PREMATURE_TIMEOUT(rtmo, 1000*1000*1000);
+ }
+#endif
+
+ cond_timeout.tv_sec = time / (1000*1000*1000);
+ cond_timeout.tv_nsec = time % (1000*1000*1000);
+ }
res = pthread_cond_timedwait(&e->cnd, &e->mtx, &cond_timeout);
- if (res == EINTR || res == ETIMEDOUT)
+ if (res == EINTR
+ || (res == ETIMEDOUT
+#if ERTS_USE_PREMATURE_TIMEOUT
+ && time == timeout_time
+#endif
+ )) {
break;
+ }
}
else
#endif
@@ -477,7 +502,11 @@ wait__(ethr_event *e, int spincount, ethr_sint64_t timeout)
struct timeval select_timeout;
#ifdef ETHR_HAVE_ETHR_GET_MONOTONIC_TIME
- time -= ethr_get_monotonic_time() - start;
+#if ERTS_USE_PREMATURE_TIMEOUT
+ restart_select:
+#endif
+
+ time = timeout_time - ethr_get_monotonic_time();
if (time <= 0)
return ETIMEDOUT;
#endif
@@ -492,6 +521,11 @@ wait__(ethr_event *e, int spincount, ethr_sint64_t timeout)
*/
time = ((time - 1) / 1000) + 1;
+#if defined(ETHR_HAVE_ETHR_GET_MONOTONIC_TIME) \
+ && ERTS_USE_PREMATURE_TIMEOUT
+ time -= ERTS_PREMATURE_TIMEOUT(time, 1000*1000);
+#endif
+
select_timeout.tv_sec = time / (1000*1000);
select_timeout.tv_usec = time % (1000*1000);
@@ -559,7 +593,11 @@ wait__(ethr_event *e, int spincount, ethr_sint64_t timeout)
val = ethr_atomic32_read(&e->state);
if (val == ETHR_EVENT_ON__)
goto return_event_on;
-
+#if defined(ETHR_HAVE_ETHR_GET_MONOTONIC_TIME) \
+ && ERTS_USE_PREMATURE_TIMEOUT
+ if (res == ETIMEDOUT)
+ goto restart_select; /* Verify timeout */
+#endif
}
return res;