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Merge pull request #4359 from mseminatore/win_perf 

Improve Windows threading performance scaling
This commit is contained in:
Martin Kroeker 2023-12-09 23:40:26 +01:00 committed by GitHub
parent 5b09833b1c efa9515a23
commit e60fb0f397
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GPG Key ID: 4AEE18F83AFDEB23
3 changed files with 114 additions and 68 deletions
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3
CONTRIBUTORS.md
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@ -216,3 +216,6 @@ In chronological order:
* Pablo Romero <https://github.com/pablorcum>
* [2022-08] Fix building from sources for QNX
* Mark Seminatore <https://github.com/mseminatore>
* [2023-11-09] Improve Windows threading performance scaling

5
common_thread.h
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@ -111,8 +111,9 @@ typedef struct blas_queue {
struct blas_queue *next;
#if defined( __WIN32__) || defined(__CYGWIN32__) || defined(_WIN32) || defined(__CYGWIN__)
CRITICAL_SECTION lock;
HANDLE finish;
// CRITICAL_SECTION lock;
// HANDLE finish;
volatile int finished;
#else
pthread_mutex_t lock;
pthread_cond_t finished;

166
driver/others/blas_server_win32.c
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@ -51,15 +51,10 @@
/* This is a thread implementation for Win32 lazy implementation */
/* Thread server common information */
typedef struct{
CRITICAL_SECTION lock;
HANDLE filled;
HANDLE killed;
blas_queue_t *queue; /* Parameter Pointer */
int shutdown; /* server shutdown flag */
} blas_pool_t;
static blas_queue_t *work_queue = NULL;
static HANDLE kickoff_event = NULL;
static CRITICAL_SECTION queue_lock;
/* We need this global for checking if initialization is finished. */
int blas_server_avail = 0;
@ -67,11 +62,19 @@ int blas_server_avail = 0;
/* Local Variables */
static BLASULONG server_lock = 0;
static blas_pool_t pool;
static HANDLE blas_threads [MAX_CPU_NUMBER];
static DWORD blas_threads_id[MAX_CPU_NUMBER];
static volatile int thread_target; // target num of live threads, volatile for cross-thread reads
#if defined (__GNUC__) && (__GNUC__ < 6)
#define WIN_CAS(dest, exch, comp) __sync_val_compare_and_swap(dest, comp, exch)
#else
#if defined(_WIN64)
#define WIN_CAS(dest, exch, comp) InterlockedCompareExchange64(dest, exch, comp)
#else
#define WIN_CAS(dest, exch, comp) InterlockedCompareExchange(dest, exch, comp)
#endif
#endif
static void legacy_exec(void *func, int mode, blas_arg_t *args, void *sb){
@ -202,14 +205,10 @@ static void legacy_exec(void *func, int mode, blas_arg_t *args, void *sb){
static DWORD WINAPI blas_thread_server(void *arg){
/* Thread identifier */
#ifdef SMP_DEBUG
BLASLONG cpu = (BLASLONG)arg;
#endif
void *buffer, *sa, *sb;
blas_queue_t *queue;
DWORD action;
HANDLE handles[] = {pool.filled, pool.killed};
/* Each server needs each buffer */
buffer = blas_memory_alloc(2);
@ -225,29 +224,44 @@ static DWORD WINAPI blas_thread_server(void *arg){
#ifdef SMP_DEBUG
fprintf(STDERR, "Server[%2ld] Waiting for Queue.\n", cpu);
#endif
// event raised when work is added to the queue
WaitForSingleObject(kickoff_event, INFINITE);
do {
action = WaitForMultipleObjects(2, handles, FALSE, INFINITE);
} while ((action != WAIT_OBJECT_0) && (action != WAIT_OBJECT_0 + 1));
if (action == WAIT_OBJECT_0 + 1) break;
if (cpu > thread_target - 2)
{
//printf("thread [%d] exiting.\n", cpu);
break; // excess thread, so worker thread exits
}
#ifdef SMP_DEBUG
fprintf(STDERR, "Server[%2ld] Got it.\n", cpu);
#endif
EnterCriticalSection(&pool.lock);
#if 1
EnterCriticalSection(&queue_lock);
queue = pool.queue;
if (queue) pool.queue = queue->next;
queue = work_queue;
if (queue)
work_queue = work_queue->next;
LeaveCriticalSection(&pool.lock);
LeaveCriticalSection(&queue_lock);
#else
volatile blas_queue_t* queue_next;
INT_PTR prev_value;
do {
queue = (volatile blas_queue_t*)work_queue;
if (!queue)
break;
queue_next = (volatile blas_queue_t*)queue->next;
prev_value = WIN_CAS((INT_PTR*)&work_queue, (INT_PTR)queue_next, (INT_PTR)queue);
} while (prev_value != queue);
#endif
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 +346,8 @@ static DWORD WINAPI blas_thread_server(void *arg){
fprintf(STDERR, "Server[%2ld] Finished!\n", cpu);
#endif
EnterCriticalSection(&queue->lock);
queue->finished = 1;
queue -> status = BLAS_STATUS_FINISHED;
LeaveCriticalSection(&queue->lock);
SetEvent(queue->finish);
}
/* Shutdown procedure */
@ -366,15 +375,16 @@ int blas_thread_init(void){
#endif
if (!blas_server_avail){
// create the kickoff Event
kickoff_event = CreateEvent(NULL, TRUE, FALSE, NULL);
InitializeCriticalSection(&pool.lock);
pool.filled = CreateEvent(NULL, FALSE, FALSE, NULL);
pool.killed = CreateEvent(NULL, TRUE, FALSE, NULL);
thread_target = blas_cpu_number;
pool.shutdown = 0;
pool.queue = NULL;
InitializeCriticalSection(&queue_lock);
for(i = 0; i < blas_cpu_number - 1; i++){
//printf("thread_init: creating thread [%d]\n", i);
blas_threads[i] = CreateThread(NULL, 0,
blas_thread_server, (void *)i,
0, &blas_threads_id[i]);
@ -409,8 +419,6 @@ int exec_blas_async(BLASLONG pos, blas_queue_t *queue){
current = queue;
while (current) {
InitializeCriticalSection(&current -> lock);
current -> finish = CreateEvent(NULL, FALSE, FALSE, NULL);
current -> position = pos;
#ifdef CONSISTENT_FPCSR
@ -418,23 +426,32 @@ int exec_blas_async(BLASLONG pos, blas_queue_t *queue){
__asm__ __volatile__ ("stmxcsr %0" : "=m" (current -> sse_mode));
#endif
current->finished = 0;
current = current -> next;
pos ++;
}
EnterCriticalSection(&pool.lock);
EnterCriticalSection(&queue_lock);
if (pool.queue) {
current = pool.queue;
while (current -> next) current = current -> next;
current -> next = queue;
} else {
pool.queue = queue;
if (!work_queue)
{
work_queue = queue;
}
else
{
blas_queue_t *next_item = work_queue;
// find the end of the work queue
while (next_item)
next_item = next_item->next;
// add new work to the end
next_item = queue;
}
LeaveCriticalSection(&pool.lock);
LeaveCriticalSection(&queue_lock);
SetEvent(pool.filled);
SetEvent(kickoff_event);
return 0;
}
@ -449,11 +466,8 @@ int exec_blas_async_wait(BLASLONG num, blas_queue_t *queue){
#ifdef SMP_DEBUG
fprintf(STDERR, "Waiting Queue ..\n");
#endif
WaitForSingleObject(queue->finish, INFINITE);
CloseHandle(queue->finish);
DeleteCriticalSection(&queue -> lock);
while (!queue->finished)
YIELDING;
queue = queue->next;
num--;
@ -462,6 +476,14 @@ int exec_blas_async_wait(BLASLONG num, blas_queue_t *queue){
#ifdef SMP_DEBUG
fprintf(STDERR, "Completely Done.\n\n");
#endif
// if work was added to the queue after this batch we can't sleep the worker threads
// by resetting the event
EnterCriticalSection(&queue_lock);
if (work_queue == NULL)
ResetEvent(kickoff_event);
LeaveCriticalSection(&queue_lock);
return 0;
}
@ -512,8 +534,6 @@ int BLASFUNC(blas_thread_shutdown)(void){
if (blas_server_avail){
SetEvent(pool.killed);
for(i = 0; i < blas_num_threads - 1; i++){
// Could also just use WaitForMultipleObjects
DWORD wait_thread_value = WaitForSingleObject(blas_threads[i], 50);
@ -528,9 +548,6 @@ int BLASFUNC(blas_thread_shutdown)(void){
CloseHandle(blas_threads[i]);
}
CloseHandle(pool.filled);
CloseHandle(pool.killed);
blas_server_avail = 0;
}
@ -552,23 +569,48 @@ void goto_set_num_threads(int num_threads)
if (num_threads > MAX_CPU_NUMBER) num_threads = MAX_CPU_NUMBER;
if (blas_server_avail && num_threads < blas_num_threads) {
LOCK_COMMAND(&server_lock);
thread_target = num_threads;
SetEvent(kickoff_event);
for (i = num_threads - 1; i < blas_num_threads - 1; i++) {
//printf("set_num_threads: waiting on thread [%d] to quit.\n", i);
WaitForSingleObject(blas_threads[i], INFINITE);
//printf("set_num_threads: thread [%d] has quit.\n", i);
CloseHandle(blas_threads[i]);
}
blas_num_threads = num_threads;
ResetEvent(kickoff_event);
UNLOCK_COMMAND(&server_lock);
}
if (num_threads > blas_num_threads) {
LOCK_COMMAND(&server_lock);
thread_target = num_threads;
//increased_threads = 1;
if (!blas_server_avail){
// create the kickoff Event
kickoff_event = CreateEvent(NULL, TRUE, FALSE, NULL);
InitializeCriticalSection(&pool.lock);
pool.filled = CreateEvent(NULL, FALSE, FALSE, NULL);
pool.killed = CreateEvent(NULL, TRUE, FALSE, NULL);
InitializeCriticalSection(&queue_lock);
pool.shutdown = 0;
pool.queue = NULL;
blas_server_avail = 1;
}
for(i = (blas_num_threads > 0) ? blas_num_threads - 1 : 0; i < num_threads - 1; i++){
//printf("set_num_threads: creating thread [%d]\n", i);
blas_threads[i] = CreateThread(NULL, 0,
blas_thread_server, (void *)i,