Re: [PATCHES] Win32 CHECK_FOR_INTERRUPTS() performance

Heads up - I have seen 2 regression hangs. I am checking further. Has 
anyone else run the regression suite with any version of this patch?

cheers

andrew

Tom Lane wrote:

>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);
>  
>
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