From bd3166220defbdc8ded78cd94aa832218f565ad6 Mon Sep 17 00:00:00 2001 From: megacz Date: Sat, 2 Feb 2002 04:31:34 +0000 Subject: [PATCH] 2002-02-01 Adam Megacz * win32-threads.cc: (_Jv_CondWait, _Jv_CondNotify, _Jv_CondNotifyAll): Corrected wait() algorithm to make it safe. (ensure_condvar_initialized, _Jv_CondInit, _Jv_CondDestroy): Added lazy creation of Win32 Events for better performance (really_start): This now uses GC_CreateThread so boehm-gc knows about new threads even when statically linked. git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@49428 138bc75d-0d04-0410-961f-82ee72b054a4 --- libjava/ChangeLog | 10 +++++ libjava/win32-threads.cc | 108 +++++++++++++++++++++++++++++++++-------------- 2 files changed, 87 insertions(+), 31 deletions(-) diff --git a/libjava/ChangeLog b/libjava/ChangeLog index 5303f43..d26c014 100644 --- a/libjava/ChangeLog +++ b/libjava/ChangeLog @@ -1,3 +1,13 @@ +2002-02-01 Adam Megacz + + * win32-threads.cc: + (_Jv_CondWait, _Jv_CondNotify, _Jv_CondNotifyAll): Corrected + wait() algorithm to make it safe. + (ensure_condvar_initialized, _Jv_CondInit, _Jv_CondDestroy): + Added lazy creation of Win32 Events for better performance + (really_start): This now uses GC_CreateThread so boehm-gc + knows about new threads even when statically linked. + 2002-02-01 Adam Megacz * include/win32-threads.h (_Jv_ConditionVariable_t): Now a struct, to diff --git a/libjava/win32-threads.cc b/libjava/win32-threads.cc index 974f156..5722330 100644 --- a/libjava/win32-threads.cc +++ b/libjava/win32-threads.cc @@ -15,7 +15,6 @@ details. */ #ifdef HAVE_BOEHM_GC extern "C" { -#include #include }; #endif /* HAVE_BOEHM_GC */ @@ -62,50 +61,97 @@ DWORD _Jv_ThreadDataKey; // Condition variables. // +// we do lazy creation of Events since CreateEvent() is insanely +// expensive, and because the rest of libgcj will call _Jv_CondInit +// when only a mutex is needed. + +inline void +ensure_condvar_initialized(_Jv_ConditionVariable_t *cv) +{ + if (cv->ev[0] == 0) { + cv->ev[0] = CreateEvent (NULL, 0, 0, NULL); + if (cv->ev[0] == 0) JvFail("CreateEvent() failed"); + cv->ev[1] = CreateEvent (NULL, 1, 0, NULL); + if (cv->ev[1] == 0) JvFail("CreateEvent() failed"); + } +} + +// Reimplementation of the general algorithm described at +// http://www.cs.wustl.edu/~schmidt/win32-cv-1.html (isomorphic to +// 3.2, not a cut-and-paste). + int -_Jv_CondWait (_Jv_ConditionVariable_t *cv, _Jv_Mutex_t *mu, jlong millis, jint nanos) +_Jv_CondWait(_Jv_ConditionVariable_t *cv, _Jv_Mutex_t *mu, jlong millis, jint nanos) { - DWORD time; - DWORD rval; - // FIXME: check for mutex ownership? + EnterCriticalSection(&cv->count_mutex); + ensure_condvar_initialized(cv); + cv->blocked_count++; + LeaveCriticalSection(&cv->count_mutex); + + DWORD time; + if ((millis == 0) && (nanos > 0)) time = 1; + else if (millis == 0) time = INFINITE; + else time = millis; _Jv_MutexUnlock (mu); - if((millis == 0) && (nanos > 0)) - time = 1; - else if(millis == 0) - time = INFINITE; - else - time = millis; + DWORD rval = WaitForMultipleObjects (2, &(cv->ev[0]), 0, time); + + EnterCriticalSection(&cv->count_mutex); + cv->blocked_count--; + // If we were unblocked by the second event (the broadcast one) and nobody is + // left, then reset the signal. + int last_waiter = rval == WAIT_OBJECT_0 + 1 && cv->blocked_count == 0; + LeaveCriticalSection(&cv->count_mutex); + + if (last_waiter) ResetEvent(&cv->ev[1]); - rval = WaitForSingleObject (*cv, time); _Jv_MutexLock (mu); - if (rval == WAIT_FAILED) - return _JV_NOT_OWNER; // FIXME? - else - return 0; + if (rval == WAIT_FAILED) return GetLastError(); + else if (rval == WAIT_TIMEOUT) return ETIMEDOUT; + else return 0; } -// -// Mutexes. -// +void +_Jv_CondInit (_Jv_ConditionVariable_t *cv) +{ + // we do lazy creation of Events since CreateEvent() is insanely expensive + cv->ev[0] = 0; + InitializeCriticalSection(&cv->count_mutex); + cv->blocked_count = 0; +} + +void +_Jv_CondDestroy (_Jv_ConditionVariable_t *cv) +{ + if (cv->ev[0] != 0) CloseHandle(cv->ev[0]); + cv = NULL; +} int -_Jv_MutexLock (_Jv_Mutex_t *mu) +_Jv_CondNotify (_Jv_ConditionVariable_t *cv, _Jv_Mutex_t *) { - DWORD rval; + EnterCriticalSection(&cv->count_mutex); + ensure_condvar_initialized(cv); + int somebody_is_blocked = cv->blocked_count > 0; + LeaveCriticalSection(&cv->count_mutex); - // FIXME: Are Win32 mutexs recursive? Should we use critical section objects - rval = WaitForSingleObject (*mu, INFINITE); + if (somebody_is_blocked) return SetEvent (cv->ev[0]) ? 0 : GetLastError(); + else return 0; +} - if (rval == WAIT_FAILED) - return GetLastError (); // FIXME: Map to errno? - else if (rval == WAIT_TIMEOUT) - return ETIMEDOUT; - else - return 0; +int +_Jv_CondNotifyAll (_Jv_ConditionVariable_t *cv, _Jv_Mutex_t *) +{ + EnterCriticalSection(&cv->count_mutex); + ensure_condvar_initialized(cv); + int somebody_is_blocked = cv->blocked_count > 0; + LeaveCriticalSection(&cv->count_mutex); + + if (somebody_is_blocked) return SetEvent (cv->ev[1]) ? 0 : GetLastError(); + else return 0; } // @@ -193,7 +239,7 @@ _Jv_ThreadUnRegister () // This function is called when a thread is started. We don't arrange // to call the `run' method directly, because this function must // return a value. -static DWORD __stdcall +static DWORD WINAPI really_start (void* x) { struct starter *info = (struct starter *) x; @@ -239,7 +285,7 @@ _Jv_ThreadStart (java::lang::Thread *thread, _Jv_Thread_t *data, _Jv_ThreadStart else data->flags |= FLAG_DAEMON; - HANDLE h = CreateThread(NULL, 0, really_start, info, 0, &id); + HANDLE h = GC_CreateThread(NULL, 0, really_start, info, 0, &id); _Jv_ThreadSetPriority(data, thread->getPriority()); //if (!h) -- 2.7.4