From d301649430be60a529d978318a1ffd62e34141f6 Mon Sep 17 00:00:00 2001 From: Mark Seminatore Date: Fri, 23 Jun 2023 19:42:27 -0700 Subject: [PATCH] fix #4063 threading perf issues on Windows --- driver/others/blas_server_win32.c | 99 +++++++++++++------------------ 1 file changed, 40 insertions(+), 59 deletions(-) diff --git a/driver/others/blas_server_win32.c b/driver/others/blas_server_win32.c index afa33cccc..1d747bd9f 100644 --- a/driver/others/blas_server_win32.c +++ b/driver/others/blas_server_win32.c @@ -52,9 +52,7 @@ /* Thread server common information */ typedef struct{ - CRITICAL_SECTION lock; - HANDLE filled; - HANDLE killed; + HANDLE taskSemaphore; blas_queue_t *queue; /* Parameter Pointer */ int shutdown; /* server shutdown flag */ @@ -68,6 +66,7 @@ int blas_server_avail = 0; static BLASULONG server_lock = 0; static blas_pool_t pool; +static BLASULONG pool_lock = 0; static HANDLE blas_threads [MAX_CPU_NUMBER]; static DWORD blas_threads_id[MAX_CPU_NUMBER]; @@ -198,7 +197,6 @@ static void legacy_exec(void *func, int mode, blas_arg_t *args, void *sb){ /* This is a main routine of threads. Each thread waits until job is */ /* queued. */ - static DWORD WINAPI blas_thread_server(void *arg){ /* Thread identifier */ @@ -207,9 +205,7 @@ static DWORD WINAPI blas_thread_server(void *arg){ #endif void *buffer, *sa, *sb; - blas_queue_t *queue; - DWORD action; - HANDLE handles[] = {pool.filled, pool.killed}; + volatile blas_queue_t *queue; /* Each server needs each buffer */ buffer = blas_memory_alloc(2); @@ -226,28 +222,32 @@ static DWORD WINAPI blas_thread_server(void *arg){ fprintf(STDERR, "Server[%2ld] Waiting for Queue.\n", cpu); #endif - do { - action = WaitForMultipleObjects(2, handles, FALSE, INFINITE); - } while ((action != WAIT_OBJECT_0) && (action != WAIT_OBJECT_0 + 1)); - - if (action == WAIT_OBJECT_0 + 1) break; + // all worker threads wait on the semaphore + WaitForSingleObject(pool.taskSemaphore, INFINITE); + // kill the thread if we are shutting down the server + if (pool.shutdown) + break; + #ifdef SMP_DEBUG fprintf(STDERR, "Server[%2ld] Got it.\n", cpu); #endif - EnterCriticalSection(&pool.lock); + // grab a queued task and update the list + volatile blas_queue_t* queue_next; + LONG64 prev_value; + do { + queue = (volatile blas_queue_t*)pool.queue; + if (!queue) + break; - queue = pool.queue; - if (queue) pool.queue = queue->next; - - LeaveCriticalSection(&pool.lock); + queue_next = (volatile blas_queue_t*)queue->next; + prev_value = InterlockedCompareExchange64((PLONG64)&pool.queue, (LONG64)queue_next, (LONG64)queue); + } while (prev_value != queue); if (queue) { int (*routine)(blas_arg_t *, void *, void *, void *, void *, BLASLONG) = queue -> routine; - if (pool.queue) SetEvent(pool.filled); - sa = queue -> sa; sb = queue -> sb; @@ -332,13 +332,8 @@ static DWORD WINAPI blas_thread_server(void *arg){ fprintf(STDERR, "Server[%2ld] Finished!\n", cpu); #endif - EnterCriticalSection(&queue->lock); - - queue -> status = BLAS_STATUS_FINISHED; - - LeaveCriticalSection(&queue->lock); - - SetEvent(queue->finish); + // mark our sub-task as complete + InterlockedDecrement(&queue->status); } /* Shutdown procedure */ @@ -353,7 +348,7 @@ static DWORD WINAPI blas_thread_server(void *arg){ } /* Initializing routine */ -int blas_thread_init(void){ + int blas_thread_init(void){ BLASLONG i; if (blas_server_avail || (blas_cpu_number <= 1)) return 0; @@ -367,9 +362,7 @@ int blas_thread_init(void){ if (!blas_server_avail){ - InitializeCriticalSection(&pool.lock); - pool.filled = CreateEvent(NULL, FALSE, FALSE, NULL); - pool.killed = CreateEvent(NULL, TRUE, FALSE, NULL); + pool.taskSemaphore = CreateSemaphore(NULL, 0, blas_cpu_number - 1, NULL); pool.shutdown = 0; pool.queue = NULL; @@ -391,11 +384,10 @@ int blas_thread_init(void){ /* User can call one of two routines. - exec_blas_async ... immediately returns after jobs are queued. + exec_blas_async ... immediately returns after jobs are queued. - exec_blas ... returns after jobs are finished. + exec_blas ... returns after jobs are finished. */ - int exec_blas_async(BLASLONG pos, blas_queue_t *queue){ #if defined(SMP_SERVER) @@ -409,8 +401,7 @@ int exec_blas_async(BLASLONG pos, blas_queue_t *queue){ current = queue; while (current) { - InitializeCriticalSection(¤t -> lock); - current -> finish = CreateEvent(NULL, FALSE, FALSE, NULL); + current->status = 1; current -> position = pos; #ifdef CONSISTENT_FPCSR @@ -422,19 +413,10 @@ int exec_blas_async(BLASLONG pos, blas_queue_t *queue){ pos ++; } - EnterCriticalSection(&pool.lock); + pool.queue = queue; - if (pool.queue) { - current = pool.queue; - while (current -> next) current = current -> next; - current -> next = queue; - } else { - pool.queue = queue; - } - - LeaveCriticalSection(&pool.lock); - - SetEvent(pool.filled); + // start up worker threads + ReleaseSemaphore(pool.taskSemaphore, pos - 1, NULL); return 0; } @@ -450,10 +432,9 @@ int exec_blas_async_wait(BLASLONG num, blas_queue_t *queue){ fprintf(STDERR, "Waiting Queue ..\n"); #endif - WaitForSingleObject(queue->finish, INFINITE); - - CloseHandle(queue->finish); - DeleteCriticalSection(&queue -> lock); + // spin-wait on each sub-task to finish + while (*((volatile int*)&queue->status)) + YIELDING; queue = queue -> next; num --; @@ -501,18 +482,21 @@ int exec_blas(BLASLONG num, blas_queue_t *queue){ /* Shutdown procedure, but user don't have to call this routine. The */ /* kernel automatically kill threads. */ - int BLASFUNC(blas_thread_shutdown)(void){ int i; +#ifdef SMP_DEBUG + fprintf(STDERR, "blas_thread_shutdown..\n"); +#endif + if (!blas_server_avail) return 0; LOCK_COMMAND(&server_lock); if (blas_server_avail){ - SetEvent(pool.killed); + pool.shutdown = 1; for(i = 0; i < blas_num_threads - 1; i++){ // Could also just use WaitForMultipleObjects @@ -528,8 +512,7 @@ int BLASFUNC(blas_thread_shutdown)(void){ CloseHandle(blas_threads[i]); } - CloseHandle(pool.filled); - CloseHandle(pool.killed); + CloseHandle(pool.taskSemaphore); blas_server_avail = 0; } @@ -559,16 +542,14 @@ void goto_set_num_threads(int num_threads) //increased_threads = 1; if (!blas_server_avail){ - InitializeCriticalSection(&pool.lock); - pool.filled = CreateEvent(NULL, FALSE, FALSE, NULL); - pool.killed = CreateEvent(NULL, TRUE, FALSE, NULL); + pool.taskSemaphore = CreateSemaphore(NULL, 0, blas_cpu_number - 1, NULL); pool.shutdown = 0; pool.queue = NULL; blas_server_avail = 1; } - for(i = blas_num_threads - 1; i < num_threads - 1; i++){ + for(i = blas_num_threads; i < num_threads - 1; i++){ blas_threads[i] = CreateThread(NULL, 0, blas_thread_server, (void *)i,