Sync from v0.13

vllm/v1/worker/ubatching.py

@@ -0,0 +1,231 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+import threading
+from typing import Optional
+
+import torch
+
+from vllm import forward_context
+from vllm.forward_context import ForwardContext
+from vllm.utils.torch_utils import current_stream
+
+_THREAD_ID_TO_CONTEXT: dict = {}
+_CURRENT_CONTEXTS: list[Optional["UBatchContext"]] = [None, None]
+
+
+class UBatchContext:
+    """
+    Context manager for micro-batching synchronization using threading events.
+    """
+
+    def __init__(
+        self,
+        id: int,
+        comm_stream: torch.cuda.Stream,
+        compute_stream: torch.cuda.Stream,
+        forward_context: ForwardContext,
+        ready_barrier: threading.Barrier,
+        cpu_wait_event: threading.Event,
+        cpu_signal_event: threading.Event,
+        gpu_comm_done_event: torch.Event,
+        gpu_compute_done_event: torch.Event,
+        schedule: str = "default",
+    ):
+        self.id = id
+        self.comm_stream = comm_stream
+        self.compute_stream = compute_stream
+        self.forward_context = forward_context
+        self.ready_barrier = ready_barrier
+        self.cpu_wait_event = cpu_wait_event
+        self.cpu_signal_event = cpu_signal_event
+        self.current_stream = compute_stream
+        self.gpu_comm_done_event = gpu_comm_done_event
+        self.gpu_compute_done_event = gpu_compute_done_event
+        self.schedule = schedule
+        self.recv_hook = None
+
+    def __enter__(self):
+        global _CURRENT_CONTEXTS, _THREAD_ID_TO_CONTEXT
+        _THREAD_ID_TO_CONTEXT[threading.get_ident()] = self.id
+        _CURRENT_CONTEXTS[self.id] = self
+        self.ready_barrier.wait()
+
+        self.cpu_wait_event.wait()
+        self.cpu_wait_event.clear()
+        self._restore_context()
+        # Assume we want to start on the compute stream
+        self.update_stream(self.compute_stream)
+        return self
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        global _CURRENT_CONTEXTS, _THREAD_ID_TO_CONTEXT
+        _CURRENT_CONTEXTS[self.id] = None
+        del _THREAD_ID_TO_CONTEXT[threading.get_ident()]
+        self.maybe_run_recv_hook()
+        self.cpu_signal_event.set()
+        self.cpu_wait_event.clear()
+        return False
+
+    def _restore_context(self):
+        forward_context._forward_context = self.forward_context
+
+    def update_stream(self, stream):
+        self.current_stream = stream
+        if current_stream() != self.current_stream:
+            torch.cuda.set_stream(self.current_stream)
+
+    def _signal_comm_done(self):
+        self.gpu_comm_done_event.record(self.comm_stream)
+
+    def _signal_compute_done(self):
+        self.gpu_compute_done_event.record(self.compute_stream)
+
+    def _wait_compute_done(self):
+        self.comm_stream.wait_event(self.gpu_compute_done_event)
+
+    def _wait_comm_done(self):
+        self.compute_stream.wait_event(self.gpu_comm_done_event)
+
+    def _cpu_yield(self):
+        # It is critical for correctness that only one thread is running
+        # at a time. These asserts just make sure that this is the only
+        # thread running before waking the other one up and going to sleep
+        assert forward_context._forward_context == self.forward_context
+        assert current_stream() == self.current_stream
+        assert not self.cpu_wait_event.is_set()
+
+        self.cpu_signal_event.set()
+        self.cpu_wait_event.wait()
+        self.cpu_wait_event.clear()
+        self._restore_context()
+
+    def switch_to_comm(self):
+        self.update_stream(self.comm_stream)
+
+    def switch_to_compute(self):
+        self.update_stream(self.compute_stream)
+
+    def switch_to_comm_sync(self):
+        self._signal_compute_done()
+        self.update_stream(self.comm_stream)
+        self._wait_compute_done()
+
+    def switch_to_compute_sync(self):
+        self._signal_comm_done()
+        self.update_stream(self.compute_stream)
+        self._wait_comm_done()
+
+    def maybe_run_recv_hook(self):
+        if self.recv_hook is not None:
+            self.recv_hook()
+            self.recv_hook = None
+
+    def yield_(self):
+        self.current_stream = current_stream()
+        self._cpu_yield()
+        self.update_stream(self.current_stream)
+
+    def yield_and_switch_from_compute_to_comm(self):
+        assert current_stream() == self.compute_stream
+        self._signal_compute_done()
+        self._cpu_yield()
+        assert self.current_stream == self.compute_stream
+        self.update_stream(self.comm_stream)
+        self._wait_compute_done()
+
+    def yield_and_switch_from_comm_to_compute(self):
+        assert current_stream() == self.comm_stream
+        self._signal_comm_done()
+        self._cpu_yield()
+        assert self.current_stream == self.comm_stream
+        self.update_stream(self.compute_stream)
+        self._wait_comm_done()
+
+
+def dbo_enabled() -> bool:
+    return len(_THREAD_ID_TO_CONTEXT) > 0
+
+
+def dbo_current_ubatch_id() -> int:
+    if len(_THREAD_ID_TO_CONTEXT) == 0:
+        return 0
+    return _THREAD_ID_TO_CONTEXT[threading.get_ident()]
+
+
+def _register_ubatch_function(func):
+    def wrapper(*args, **kwargs):
+        if len(_THREAD_ID_TO_CONTEXT) > 0:
+            ctx_idx = _THREAD_ID_TO_CONTEXT[threading.get_ident()]
+            ctx = _CURRENT_CONTEXTS[ctx_idx]
+            func(ctx, *args, **kwargs)
+
+    return wrapper
+
+
+dbo_maybe_run_recv_hook = _register_ubatch_function(UBatchContext.maybe_run_recv_hook)
+dbo_yield = _register_ubatch_function(UBatchContext.yield_)
+dbo_yield_and_switch_from_compute_to_comm = _register_ubatch_function(
+    UBatchContext.yield_and_switch_from_compute_to_comm
+)
+dbo_yield_and_switch_from_comm_to_compute = _register_ubatch_function(
+    UBatchContext.yield_and_switch_from_comm_to_compute
+)
+dbo_switch_to_comm = _register_ubatch_function(UBatchContext.switch_to_comm)
+dbo_switch_to_compute = _register_ubatch_function(UBatchContext.switch_to_compute)
+dbo_switch_to_comm_sync = _register_ubatch_function(UBatchContext.switch_to_comm_sync)
+dbo_switch_to_compute_sync = _register_ubatch_function(
+    UBatchContext.switch_to_compute_sync
+)
+
+
+def dbo_register_recv_hook(recv_hook):
+    if len(_THREAD_ID_TO_CONTEXT) > 0:
+        ctx_idx = _THREAD_ID_TO_CONTEXT[threading.get_ident()]
+        next_ctx = _CURRENT_CONTEXTS[(ctx_idx + 1) % 2]
+        next_ctx.recv_hook = recv_hook
+
+
+def dbo_get_previous_event(func, *args, **kwargs):
+    if len(_THREAD_ID_TO_CONTEXT) > 0:
+        ctx_idx = _THREAD_ID_TO_CONTEXT[threading.get_ident()]
+        ctx = _CURRENT_CONTEXTS[ctx_idx]
+        # execute callable on the ubatch compute stream to record/wait events there
+        with torch.cuda.stream(ctx.compute_stream):
+            return func(*args, **kwargs)
+
+
+def make_ubatch_contexts(
+    num_micro_batches: int,
+    compute_stream: torch.cuda.Stream,
+    comm_stream: torch.cuda.Stream,
+    forward_contexts: list[ForwardContext],
+    ready_barrier: threading.Barrier,
+    schedule: str = "default",
+) -> list[UBatchContext]:
+    assert num_micro_batches == 2, "only been tested with 2 micro-batches"
+    """
+    Create a context manager for micro-batching synchronization.
+    """
+    cpu_events = [threading.Event() for _ in range(num_micro_batches)]
+    gpu_comm_done_events = [torch.Event() for _ in range(num_micro_batches)]
+    gpu_compute_done_events = [torch.Event() for _ in range(num_micro_batches)]
+
+    assert len(forward_contexts) == 2
+
+    ctxs = []
+    for i in range(num_micro_batches):
+        ctx = UBatchContext(
+            id=i,
+            compute_stream=compute_stream,
+            comm_stream=comm_stream,
+            forward_context=forward_contexts[i],
+            ready_barrier=ready_barrier,
+            cpu_wait_event=cpu_events[i],
+            cpu_signal_event=cpu_events[(i + 1) % num_micro_batches],
+            gpu_comm_done_event=gpu_comm_done_events[i],
+            gpu_compute_done_event=gpu_compute_done_events[i],
+            schedule=schedule,
+        )
+        ctxs.append(ctx)
+
+    return ctxs