Fix Windows setitimer() emulation to not depend on delivering an APC

to the main thread.  This allows removal of WaitForSingleObjectEx() calls
from the main thread, thereby allowing us to re-enable Qingqing Zhou's
CHECK_FOR_INTERRUPTS performance improvement.  Qingqing, Magnus, et al.

diff --git a/src/backend/port/win32/signal.c b/src/backend/port/win32/signal.c
index fa7d8cf6a2c0f5305067ef4fdfcd472afeaf6621..3204c9c20e19be12c6a977cca6411facbe7ca4e2 100644 (file)
--- a/src/backend/port/win32/signal.c
+++ b/src/backend/port/win32/signal.c
@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
  *
  * IDENTIFICATION
- *   $PostgreSQL: pgsql/src/backend/port/win32/signal.c,v 1.13 2005/10/21 21:43:45 tgl Exp $
+ *   $PostgreSQL: pgsql/src/backend/port/win32/signal.c,v 1.14 2005/10/25 15:15:16 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -89,16 +89,6 @@ pgwin32_signal_initialize(void)
                (errmsg_internal("failed to set console control handler")));
 }
 
-/*
- * Support routine for CHECK_FOR_INTERRUPTS() macro
- */
-void
-pgwin32_check_queued_signals(void)
-{
-   if (WaitForSingleObjectEx(pgwin32_signal_event, 0, TRUE) == WAIT_OBJECT_0)
-       pgwin32_dispatch_queued_signals();
-}
-
 /*
  * Dispatch all signals currently queued and not blocked
  * Blocked signals are ignored, and will be fired at the time of

diff --git a/src/backend/port/win32/socket.c b/src/backend/port/win32/socket.c
index 808977a2374122ee78f12b5d10603f558eb18740..b4bd121ca94e4dfd1c74f5796c634b6f1ae54886 100644 (file)
--- a/src/backend/port/win32/socket.c
+++ b/src/backend/port/win32/socket.c
@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
  *
  * IDENTIFICATION
- *   $PostgreSQL: pgsql/src/backend/port/win32/socket.c,v 1.9 2005/10/15 02:49:23 momjian Exp $
+ *   $PostgreSQL: pgsql/src/backend/port/win32/socket.c,v 1.10 2005/10/25 15:15:16 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -93,7 +93,7 @@ TranslateSocketError(void)
 static int
 pgwin32_poll_signals(void)
 {
-   if (WaitForSingleObjectEx(pgwin32_signal_event, 0, TRUE) == WAIT_OBJECT_0)
+   if (UNBLOCKED_SIGNAL_QUEUE())
    {
        pgwin32_dispatch_queued_signals();
        errno = EINTR;

diff --git a/src/backend/port/win32/timer.c b/src/backend/port/win32/timer.c
index c31c7bc114e37661cd97703aebe96c801b2bb5b4..b6c0b407e6e2df48b741af982f4b7a958b063735 100644 (file)
--- a/src/backend/port/win32/timer.c
+++ b/src/backend/port/win32/timer.c
@@ -3,10 +3,15 @@
  * timer.c
  *   Microsoft Windows Win32 Timer Implementation
  *
+ *    Limitations of this implementation:
+ *
+ *    - Does not support interval timer (value->it_interval)
+ *    - Only supports ITIMER_REAL
+ *
  * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
  *
  * IDENTIFICATION
- *   $PostgreSQL: pgsql/src/backend/port/win32/timer.c,v 1.5 2004/12/31 22:00:37 pgsql Exp $
+ *   $PostgreSQL: pgsql/src/backend/port/win32/timer.c,v 1.6 2005/10/25 15:15:16 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -16,56 +21,98 @@
 #include "libpq/pqsignal.h"
 
 
-static HANDLE timerHandle = INVALID_HANDLE_VALUE;
+/* Communication area for inter-thread communication */
+typedef struct timerCA {
+   struct itimerval value;
+   HANDLE event;
+   CRITICAL_SECTION crit_sec;
+} timerCA;
+
+static timerCA timerCommArea;
+static HANDLE timerThreadHandle = INVALID_HANDLE_VALUE;
 
-static VOID CALLBACK
-timer_completion(LPVOID arg, DWORD timeLow, DWORD timeHigh)
+
+/* Timer management thread */
+static DWORD WINAPI
+pg_timer_thread(LPVOID param)
 {
-   pg_queue_signal(SIGALRM);
-}
+   DWORD waittime;
+
+   Assert(param == NULL);
 
+   waittime = INFINITE;
+
+   for (;;)
+   {
+       int r;
+
+       r = WaitForSingleObjectEx(timerCommArea.event, waittime, FALSE);
+       if (r == WAIT_OBJECT_0)
+       {
+           /* Event signalled from main thread, change the timer */
+           EnterCriticalSection(&timerCommArea.crit_sec);
+           if (timerCommArea.value.it_value.tv_sec == 0 &&
+               timerCommArea.value.it_value.tv_usec == 0)
+               waittime = INFINITE; /* Cancel the interrupt */
+           else
+               waittime = timerCommArea.value.it_value.tv_usec / 10 + timerCommArea.value.it_value.tv_sec * 1000;
+           ResetEvent(timerCommArea.event);
+           LeaveCriticalSection(&timerCommArea.crit_sec);
+       }
+       else if (r == WAIT_TIMEOUT)
+       {
+           /* Timeout expired, signal SIGALRM and turn it off */
+           pg_queue_signal(SIGALRM);
+           waittime = INFINITE;
+       }
+       else
+       {
+           /* Should never happen */
+           Assert(false);
+       }
+   }
+
+   return 0;
+}
 
 /*
- * Limitations of this implementation:
- *
- * - Does not support setting ovalue
- * - Does not support interval timer (value->it_interval)
- * - Only supports ITIMER_REAL
+ * Win32 setitimer emulation by creating a persistent thread
+ * to handle the timer setting and notification upon timeout.
  */
 int
 setitimer(int which, const struct itimerval * value, struct itimerval * ovalue)
 {
-   LARGE_INTEGER dueTime;
-
-   Assert(ovalue == NULL);
    Assert(value != NULL);
    Assert(value->it_interval.tv_sec == 0 && value->it_interval.tv_usec == 0);
    Assert(which == ITIMER_REAL);
 
-   if (timerHandle == INVALID_HANDLE_VALUE)
+   if (timerThreadHandle == INVALID_HANDLE_VALUE)
    {
-       /* First call in this backend, create new timer object */
-       timerHandle = CreateWaitableTimer(NULL, TRUE, NULL);
-       if (timerHandle == NULL)
+       /* First call in this backend, create event and the timer thread */
+       timerCommArea.event = CreateEvent(NULL, TRUE, FALSE, NULL);
+       if (timerCommArea.event == NULL)
            ereport(FATAL,
-                   (errmsg_internal("failed to create waitable timer: %i", (int) GetLastError())));
-   }
+                   (errmsg_internal("failed to create timer event: %d",
+                                    (int) GetLastError())));
 
-   if (value->it_value.tv_sec == 0 &&
-       value->it_value.tv_usec == 0)
-   {
-       /* Turn timer off */
-       CancelWaitableTimer(timerHandle);
-       return 0;
-   }
+       MemSet(&timerCommArea.value, 0, sizeof(struct itimerval));
+
+       InitializeCriticalSection(&timerCommArea.crit_sec);
 
-   /* Negative time to SetWaitableTimer means relative time */
-   dueTime.QuadPart = -(value->it_value.tv_usec * 10 + value->it_value.tv_sec * 10000000L);
+       timerThreadHandle = CreateThread(NULL, 0, pg_timer_thread, NULL, 0, NULL);
+       if (timerThreadHandle == INVALID_HANDLE_VALUE)
+           ereport(FATAL,
+                   (errmsg_internal("failed to create timer thread: %d",
+                                    (int) GetLastError())));
+   }
 
-   /* Turn timer on, or change timer */
-   if (!SetWaitableTimer(timerHandle, &dueTime, 0, timer_completion, NULL, FALSE))
-       ereport(FATAL,
-               (errmsg_internal("failed to set waitable timer: %i", (int) GetLastError())));
+   /* Request the timer thread to change settings */
+   EnterCriticalSection(&timerCommArea.crit_sec);
+   if (ovalue)
+       *ovalue = timerCommArea.value;
+   timerCommArea.value = *value;
+   LeaveCriticalSection(&timerCommArea.crit_sec);
+   SetEvent(timerCommArea.event);
 
    return 0;
 }

diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index f82fffed77c8655d2ac353b024761e2fac40af0e..fc13891e414b5b7d14d47c18b0701b50ffadf99b 100644 (file)
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -13,7 +13,7 @@
  * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/miscadmin.h,v 1.182 2005/10/22 17:09:48 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/miscadmin.h,v 1.183 2005/10/25 15:15:16 tgl Exp $
  *
  * NOTES
  *   some of the information in this file should be moved to other files.
@@ -88,7 +88,8 @@ do { \
 
 #define CHECK_FOR_INTERRUPTS() \
 do { \
-   pgwin32_check_queued_signals(); \
+   if (UNBLOCKED_SIGNAL_QUEUE()) \
+       pgwin32_dispatch_queued_signals(); \
    if (InterruptPending) \
        ProcessInterrupts(); \
 } while(0)

diff --git a/src/include/port/win32.h b/src/include/port/win32.h
index 9d1a6da6c6c23c9c6de3ace4fd2f6bc8b0d4e62d..5bf6ce208fc1cd7f87b3a190fca882b2c25c00f2 100644 (file)
--- a/src/include/port/win32.h
+++ b/src/include/port/win32.h
@@ -1,4 +1,4 @@
-/* $PostgreSQL: pgsql/src/include/port/win32.h,v 1.48 2005/10/21 21:43:46 tgl Exp $ */
+/* $PostgreSQL: pgsql/src/include/port/win32.h,v 1.49 2005/10/25 15:15:16 tgl Exp $ */
 
 /* undefine and redefine after #include */
 #undef mkdir
@@ -224,7 +224,6 @@ extern HANDLE pgwin32_initial_signal_pipe;
 
 void       pgwin32_signal_initialize(void);
 HANDLE     pgwin32_create_signal_listener(pid_t pid);
-void       pgwin32_check_queued_signals(void);
 void       pgwin32_dispatch_queued_signals(void);
 void       pg_queue_signal(int signum);