[newlib-cygwin] Cygwin: posix timers: fix overrun count always being 1 too big
Corinna Vinschen
corinna@sourceware.org
Tue Jan 22 17:20:00 GMT 2019
https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=1f10a00ba717b22b154205508e60af0dcb641ed3
commit 1f10a00ba717b22b154205508e60af0dcb641ed3
Author: Corinna Vinschen <corinna@vinschen.de>
Date: Tue Jan 22 18:20:18 2019 +0100
Cygwin: posix timers: fix overrun count always being 1 too big
Combine with a bit of cleanup:
- Drop overrun_event_running in favor of overrun_count being -1.
- Fix include guard in posix_timer.h.
- Drop ununsed function timespec_to_us.
- Don't use Interlocked functions without need.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Diff:
---
winsup/cygwin/posix_timer.cc | 49 +++++++++++++++-----------------------------
winsup/cygwin/posix_timer.h | 9 ++++----
2 files changed, 21 insertions(+), 37 deletions(-)
diff --git a/winsup/cygwin/posix_timer.cc b/winsup/cygwin/posix_timer.cc
index 5f569b6..a76ba06 100644
--- a/winsup/cygwin/posix_timer.cc
+++ b/winsup/cygwin/posix_timer.cc
@@ -17,8 +17,7 @@ details. */
#include "posix_timer.h"
#include <sys/param.h>
-#define OVR_EVENT_DISARMED 0
-#define OVR_EVENT_ARMED 1
+#define OVR_DISARMED -1LL
timer_tracker NO_COPY itimer_tracker (CLOCK_REALTIME, NULL);
@@ -34,15 +33,15 @@ timer_tracker::cancel ()
{
res = WaitForSingleObject (sync_thr, INFINITE);
if (res != WAIT_OBJECT_0)
- system_printf ("WFSO returned unexpected value %u, %E", res);
+ debug_printf ("WFSO returned unexpected value %u, %E", res);
}
return true;
}
timer_tracker::timer_tracker (clockid_t c, const sigevent *e)
: magic (TT_MAGIC), clock_id (c), timer (NULL), cancel_evt (NULL),
- sync_thr (NULL), interval (0), exp_ts (0), overrun_event_running (0),
- overrun_count_curr (0), overrun_count (0)
+ sync_thr (NULL), interval (0), exp_ts (0), overrun_count_curr (0),
+ overrun_count (OVR_DISARMED)
{
srwlock = SRWLOCK_INIT;
if (e != NULL)
@@ -66,25 +65,14 @@ timer_tracker::~timer_tracker ()
ReleaseSRWLockExclusive (&srwlock);
}
-static inline int64_t
-timespec_to_us (const timespec& ts)
-{
- int64_t res = ts.tv_sec;
- res *= USPERSEC;
- res += (ts.tv_nsec + (NSPERSEC/USPERSEC) - 1) / (NSPERSEC/USPERSEC);
- return res;
-}
-
/* Returns 0 if arming successful, -1 if a signal is already queued.
If so, it also increments overrun_count. Only call under lock! */
-LONG
-timer_tracker::arm_overrun_event ()
+bool
+timer_tracker::arm_overrun_event (LONG64 exp_cnt)
{
- LONG ret;
+ bool ret = (overrun_count != OVR_DISARMED);
- ret = InterlockedExchange (&overrun_event_running, OVR_EVENT_ARMED);
- if (ret == OVR_EVENT_ARMED)
- ret = InterlockedIncrement64 (&overrun_count);
+ overrun_count += exp_cnt;
return ret;
}
@@ -94,18 +82,17 @@ timer_tracker::disarm_overrun_event ()
LONG ret;
AcquireSRWLockExclusive (&srwlock);
- ret = InterlockedExchange (&overrun_event_running, OVR_EVENT_DISARMED);
- if (ret == OVR_EVENT_ARMED)
+ if (overrun_count != OVR_DISARMED)
{
LONG64 ov_cnt;
- InterlockedExchange64 (&ov_cnt, overrun_count);
+ ov_cnt = overrun_count;
if (ov_cnt > DELAYTIMER_MAX || ov_cnt < 0)
overrun_count_curr = DELAYTIMER_MAX;
else
overrun_count_curr = ov_cnt;
ret = overrun_count_curr;
- InterlockedExchange64 (&overrun_count, 0);
+ overrun_count = OVR_DISARMED;
}
ReleaseSRWLockExclusive (&srwlock);
return ret;
@@ -150,18 +137,17 @@ timer_tracker::thread_func ()
ReleaseSRWLockExclusive (&srwlock);
goto out;
}
+ LONG64 exp_cnt = 0;
if (interval)
{
/* Compute expiration count. */
LONG64 now = get_clock_now ();
LONG64 ts = get_exp_ts ();
- LONG64 exp_cnt;
/* Make concessions for unexact realtime clock */
if (ts > now)
ts = now - 1;
- exp_cnt = (now - ts) / interval;
- InterlockedAdd64 (&overrun_count, exp_cnt);
+ exp_cnt = (now - ts + interval - 1) / interval;
ts += interval * exp_cnt;
set_exp_ts (ts);
/* NtSetTimer allows periods of up to 24 days only. If the time
@@ -180,7 +166,7 @@ timer_tracker::thread_func ()
{
case SIGEV_SIGNAL:
{
- if (arm_overrun_event ())
+ if (arm_overrun_event (exp_cnt))
{
debug_printf ("%p timer signal already queued", this);
break;
@@ -196,7 +182,7 @@ timer_tracker::thread_func ()
}
case SIGEV_THREAD:
{
- if (arm_overrun_event ())
+ if (arm_overrun_event (exp_cnt))
{
debug_printf ("%p timer thread already queued", this);
break;
@@ -227,7 +213,7 @@ timer_tracker::thread_func ()
{
memset (&time_spec, 0, sizeof time_spec);
exp_ts = 0;
- overrun_event_running = OVR_EVENT_DISARMED;
+ overrun_count = OVR_DISARMED;
ReleaseSRWLockExclusive (&srwlock);
goto out;
}
@@ -383,8 +369,7 @@ timer_tracker::settime (int flags, const itimerspec *new_value,
set_exp_ts (ts);
time_spec = *new_value;
overrun_count_curr = 0;
- overrun_count = 0;
- overrun_event_running = OVR_EVENT_DISARMED;
+ overrun_count = OVR_DISARMED;
/* Note: Advanced Power Settings -> Sleep -> Allow Wake Timers
since W10 1709 */
Resume = (clock_id == CLOCK_REALTIME_ALARM
diff --git a/winsup/cygwin/posix_timer.h b/winsup/cygwin/posix_timer.h
index f69a179..e1cfe84 100644
--- a/winsup/cygwin/posix_timer.h
+++ b/winsup/cygwin/posix_timer.h
@@ -6,8 +6,8 @@ This software is a copyrighted work licensed under the terms of the
Cygwin license. Please consult the file "CYGWIN_LICENSE" for
details. */
-#ifndef __TIMER_H__
-#define __TIMER_H__
+#ifndef __POSIX_TIMER_H__
+#define __POSIX_TIMER_H__
#define TT_MAGIC 0x513e4a1c
class timer_tracker
@@ -22,7 +22,6 @@ class timer_tracker
HANDLE sync_thr;
LONG64 interval;
LONG64 exp_ts;
- LONG overrun_event_running;
LONG overrun_count_curr;
LONG64 overrun_count;
@@ -42,7 +41,7 @@ class timer_tracker
LONG64 get_interval () const { return interval; }
void set_exp_ts (LONG64 ts) { exp_ts = ts; }
- LONG arm_overrun_event ();
+ bool arm_overrun_event (LONG64);
LONG disarm_overrun_event ();
int gettime (itimerspec *, bool);
@@ -52,4 +51,4 @@ class timer_tracker
static void fixup_after_fork ();
};
-#endif /* __TIMER_H__ */
+#endif /* __POSIX_TIMER_H__ */
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