Re: [PATCHES] Win32 CHECK_FOR_INTERRUPTS() performance
От | Qingqing Zhou |
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Тема | Re: [PATCHES] Win32 CHECK_FOR_INTERRUPTS() performance |
Дата | |
Msg-id | Pine.LNX.4.58.0510221517060.12644@eon.cs обсуждение исходный текст |
Ответ на | Re: [PATCHES] Win32 CHECK_FOR_INTERRUPTS() performance (Tom Lane <tgl@sss.pgh.pa.us>) |
Ответы |
Re: [PATCHES] Win32 CHECK_FOR_INTERRUPTS() performance
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Список | pgsql-hackers |
> Andrew Dunstan <andrew@dunslane.net> writes: > > The hard part looks to be cancelling/changing the timer, which means > > that we can't just create a set and forget listener thread for a given > > timeout. Otherwise that seems to me the straightforward approach. > > Yeah. I think probably the cleanest way is to create a persistent > thread that manages the timer. We need a way for the main thread to > tell it to cancel the timer or change the setting. Dunno enough about > Windows' interthread communication primitives to propose details. > Oh my ... fortunately we got a timer test in regression. I've come up with a quick patch implementing above discussions. Also, seems by patching this, we can support setitimer(.,.,ovalue != NULL) -- because it is saved in the memory. Regards, Qingqing --- Index: timer.c =================================================================== RCS file: /projects/cvsroot/pgsql/src/backend/port/win32/timer.c,v retrieving revision 1.5 diff -u -r1.5 timer.c --- timer.c 31 Dec 2004 22:00:37 -0000 1.5 +++ timer.c 23 Oct 2005 00:53:56 -0000 @@ -15,8 +15,16 @@ #include "libpq/pqsignal.h" +/* Communication area of timer settings */ +typedef struct timerCA{ + int which; + struct itimerval value; + HANDLE event; +}timerCA; +static timerCA timerCommArea;static HANDLE timerHandle = INVALID_HANDLE_VALUE; +static HANDLE timerThreadHandle = INVALID_HANDLE_VALUE; static VOID CALLBACKtimer_completion(LPVOID arg, DWORD timeLow, DWORD timeHigh) @@ -28,16 +36,14 @@/* * Limitations of this implementation: * - * - Does not support setting ovalue * - Does not support interval timer (value->it_interval) * - Only supports ITIMER_REAL*/ -int -setitimer(int which, const struct itimerval * value, struct itimerval * ovalue) +static int +do_setitimer(int which, const struct itimerval * value){ 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); @@ -69,3 +75,56 @@ return 0;} + +/* Timer ticking thread */ +static DWORD WINAPI +pg_timer_thread(LPVOID param) +{ + Assert(param == NULL); + + for (;;) + { + if (WaitForSingleObjectEx(timerCommArea.event, INFINITE, TRUE) == WAIT_OBJECT_0) + { + do_setitimer(timerCommArea.which, &timerCommArea.value); + ResetEvent(timerCommArea.event); + } + } + + return 0; +} + +/* + * 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) +{ + Assert(value != NULL); + + if (timerThreadHandle == INVALID_HANDLE_VALUE) + { + /* 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 timer event: %d", (int) GetLastError()))); + MemSet(&timerCommArea.value, 0, sizeof(struct itimerval)); + + 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()))); + } + + /* Request the timer thread to change settings */ + if (ovalue) + *ovalue = timerCommArea.value; + timerCommArea.which = which; + timerCommArea.value = *value; + SetEvent(timerCommArea.event); + + /* Timer thread will handle possible errors */ + return 0; +}
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