Re: [PATCHES] Win32 CHECK_FOR_INTERRUPTS() performance tweak

I wrote:
> BTW, expanding on Andrew's comment, ISTM we could move the kernel call
> out of the macro, ie make it look like ...

I've applied the attached version of Qingqing's revised patch. I'm not
in a position to test it, and am about to go out for the evening, but if
anyone can check the committed version soon and verify that I didn't
break anything ...

(BTW, DLLIMPORT is only needed in extern declarations, not in the actual
definition of the variable.)

regards, tom lane

*** src/backend/port/win32/signal.c.orig Fri Oct 14 22:59:56 2005
--- src/backend/port/win32/signal.c Fri Oct 21 17:36:24 2005
***************
*** 15,32 ****

#include <libpq/pqsignal.h>

!
! /* pg_signal_crit_sec is used to protect only pg_signal_queue. That is the only
! * variable that can be accessed from the signal sending threads! */
static CRITICAL_SECTION pg_signal_crit_sec;
- static int pg_signal_queue;

static pqsigfunc pg_signal_array[PG_SIGNAL_COUNT];
static pqsigfunc pg_signal_defaults[PG_SIGNAL_COUNT];
- static int pg_signal_mask;
-
- DLLIMPORT HANDLE pgwin32_signal_event;
- HANDLE pgwin32_initial_signal_pipe = INVALID_HANDLE_VALUE;


/* Signal handling thread function */
--- 15,40 ----

#include <libpq/pqsignal.h>

! /*
! * These are exported for use by the UNBLOCKED_SIGNAL_QUEUE() macro.
! * pg_signal_queue must be volatile since it is changed by the signal
! * handling thread and inspected without any lock by the main thread.
! * pg_signal_mask is only changed by main thread so shouldn't need it.
! */
! volatile int pg_signal_queue;
! int pg_signal_mask;
!
! HANDLE pgwin32_signal_event;
! HANDLE pgwin32_initial_signal_pipe = INVALID_HANDLE_VALUE;
!
! /*
! * pg_signal_crit_sec is used to protect only pg_signal_queue. That is the only
! * variable that can be accessed from the signal sending threads!
! */
static CRITICAL_SECTION pg_signal_crit_sec;

static pqsigfunc pg_signal_array[PG_SIGNAL_COUNT];
static pqsigfunc pg_signal_defaults[PG_SIGNAL_COUNT];


/* Signal handling thread function */
***************
*** 81,101 ****
(errmsg_internal("failed to set console control handler")));
}


! /* Dispatch all signals currently queued and not blocked
* Blocked signals are ignored, and will be fired at the time of
! * the sigsetmask() call. */
void
pgwin32_dispatch_queued_signals(void)
{
int i;

EnterCriticalSection(&pg_signal_crit_sec);
! while (pg_signal_queue & ~pg_signal_mask)
{
/* One or more unblocked signals queued for execution */
!
! int exec_mask = pg_signal_queue & ~pg_signal_mask;

for (i = 0; i < PG_SIGNAL_COUNT; i++)
{
--- 89,119 ----
(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
! * the sigsetmask() call.
! */
void
pgwin32_dispatch_queued_signals(void)
{
int i;

EnterCriticalSection(&pg_signal_crit_sec);
! while (UNBLOCKED_SIGNAL_QUEUE())
{
/* One or more unblocked signals queued for execution */
! int exec_mask = UNBLOCKED_SIGNAL_QUEUE();

for (i = 0; i < PG_SIGNAL_COUNT; i++)
{
*** src/include/miscadmin.h.orig Fri Oct 14 23:00:22 2005
--- src/include/miscadmin.h Fri Oct 21 17:36:18 2005
***************
*** 83,97 ****
if (InterruptPending) \
ProcessInterrupts(); \
} while(0)
#else /* WIN32 */

#define CHECK_FOR_INTERRUPTS() \
do { \
! if (WaitForSingleObjectEx(pgwin32_signal_event,0,TRUE) == WAIT_OBJECT_0) \
! pgwin32_dispatch_queued_signals(); \
if (InterruptPending) \
ProcessInterrupts(); \
} while(0)
#endif /* WIN32 */


--- 83,99 ----
if (InterruptPending) \
ProcessInterrupts(); \
} while(0)
+
#else /* WIN32 */

#define CHECK_FOR_INTERRUPTS() \
do { \
! if (UNBLOCKED_SIGNAL_QUEUE()) \
! pgwin32_check_queued_signals(); \
if (InterruptPending) \
ProcessInterrupts(); \
} while(0)
+
#endif /* WIN32 */


*** src/include/port/win32.h.orig Fri Oct 14 23:00:30 2005
--- src/include/port/win32.h Fri Oct 21 17:36:12 2005
***************
*** 214,224 ****


/* In backend/port/win32/signal.c */
! extern DLLIMPORT HANDLE pgwin32_signal_event;
extern HANDLE pgwin32_initial_signal_pipe;

void pgwin32_signal_initialize(void);
HANDLE pgwin32_create_signal_listener(pid_t pid);
void pgwin32_dispatch_queued_signals(void);
void pg_queue_signal(int signum);

--- 214,230 ----


/* In backend/port/win32/signal.c */
! extern DLLIMPORT volatile int pg_signal_queue;
! extern DLLIMPORT int pg_signal_mask;
! extern HANDLE pgwin32_signal_event;
extern HANDLE pgwin32_initial_signal_pipe;

+ #define UNBLOCKED_SIGNAL_QUEUE() (pg_signal_queue & ~pg_signal_mask)
+
+
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);