diff --git a/core/templates/command_queue_mt.h b/core/templates/command_queue_mt.h index 9f9b77d9d04..dbf938a117e 100644 --- a/core/templates/command_queue_mt.h +++ b/core/templates/command_queue_mt.h @@ -327,7 +327,6 @@ class CommandQueueMT { enum { DEFAULT_COMMAND_MEM_SIZE_KB = 256, - SYNC_SEMAPHORES = 8 }; BinaryMutex mutex; @@ -335,6 +334,7 @@ class CommandQueueMT { ConditionVariable sync_cond_var; uint32_t sync_head = 0; uint32_t sync_tail = 0; + uint32_t sync_awaiters = 0; WorkerThreadPool::TaskID pump_task_id = WorkerThreadPool::INVALID_TASK_ID; uint64_t flush_read_ptr = 0; @@ -349,6 +349,15 @@ class CommandQueueMT { return cmd; } + _FORCE_INLINE_ void _prevent_sync_wraparound() { + bool safe_to_reset = !sync_awaiters; + bool already_sync_to_latest = sync_head == sync_tail; + if (safe_to_reset && already_sync_to_latest) { + sync_head = 0; + sync_tail = 0; + } + } + void _flush() { if (unlikely(flush_read_ptr)) { // Re-entrant call. @@ -365,7 +374,9 @@ class CommandQueueMT { cmd->call(); if (unlikely(cmd->sync)) { sync_head++; + unlock(); // Give an opportunity to awaiters right away. sync_cond_var.notify_all(); + lock(); } // If the command involved reallocating the buffer, the address may have changed. @@ -378,14 +389,20 @@ class CommandQueueMT { command_mem.clear(); flush_read_ptr = 0; + + _prevent_sync_wraparound(); + unlock(); } _FORCE_INLINE_ void _wait_for_sync(MutexLock &p_lock) { + sync_awaiters++; uint32_t sync_head_goal = sync_tail; do { sync_cond_var.wait(p_lock); - } while (sync_head != sync_head_goal); // Can't use lower-than because of wraparound. + } while (sync_head < sync_head_goal); + sync_awaiters--; + _prevent_sync_wraparound(); } void _no_op() {}