First commit

vllm/model_executor/models/mamba_cache.py

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+from typing import Dict, List, Optional
+
+import torch
+
+from vllm.attention.backends.abstract import AttentionMetadata
+
+
+class MambaCacheManager:
+
+    def __init__(self, dtype, num_mamba_layers, max_batch_size,
+                 conv_state_shape, temporal_state_shape):
+
+        conv_state = torch.empty(size=(num_mamba_layers, max_batch_size) +
+                                 conv_state_shape,
+                                 dtype=dtype,
+                                 device="cuda")
+        temporal_state = torch.empty(size=(num_mamba_layers, max_batch_size) +
+                                     temporal_state_shape,
+                                     dtype=dtype,
+                                     device="cuda")
+
+        self.mamba_cache = (conv_state, temporal_state)
+
+        # Maps between the request id and a dict that maps between the seq_id
+        # and its index inside the self.mamba_cache
+        self.mamba_cache_indices_mapping: Dict[str, Dict[int, int]] = {}
+
+    def current_run_tensors(self, input_ids: torch.Tensor,
+                            attn_metadata: AttentionMetadata, **kwargs):
+        """
+        Return the tensors for the current run's conv and ssm state.
+        """
+        if "seqlen_agnostic_capture_inputs" not in kwargs:
+            # We get here only on Prefill/Eager mode runs
+            request_ids_to_seq_ids = kwargs["request_ids_to_seq_ids"]
+            finished_requests_ids = kwargs["finished_requests_ids"]
+
+            self._release_finished_requests(finished_requests_ids)
+            mamba_cache_tensors = self._prepare_current_run_mamba_cache(
+                request_ids_to_seq_ids, finished_requests_ids)
+
+        else:
+            # CUDA graph capturing runs
+            mamba_cache_tensors = kwargs["seqlen_agnostic_capture_inputs"]
+
+        return mamba_cache_tensors
+
+    def copy_inputs_before_cuda_graphs(self, input_buffers, **kwargs):
+        """
+        Copy the relevant Mamba cache into the CUDA graph input buffer
+        that was provided during the capture runs
+        (JambaForCausalLM.mamba_gc_cache_buffer).
+        """
+        assert all(
+            key in kwargs
+            for key in ["request_ids_to_seq_ids", "finished_requests_ids"])
+        finished_requests_ids = kwargs["finished_requests_ids"]
+        request_ids_to_seq_ids = kwargs["request_ids_to_seq_ids"]
+
+        self._release_finished_requests(finished_requests_ids)
+        self._prepare_current_run_mamba_cache(request_ids_to_seq_ids,
+                                              finished_requests_ids)
+
+    def get_seqlen_agnostic_capture_inputs(self, batch_size: int):
+        """
+        Provide the CUDA graph capture runs with a buffer in adjusted size.
+        The buffer is used to maintain the Mamba Cache during the CUDA graph
+        replay runs.
+        """
+        return tuple(buffer[:, :batch_size] for buffer in self.mamba_cache)
+
+    def _swap_mamba_cache(self, from_index: int, to_index: int):
+        assert len(self.mamba_cache) > 0
+        for cache_t in self.mamba_cache:
+            cache_t[:, [to_index,from_index]] = \
+             cache_t[:, [from_index,to_index]]
+
+    def _copy_mamba_cache(self, from_index: int, to_index: int):
+        assert len(self.mamba_cache) > 0
+        for cache_t in self.mamba_cache:
+            cache_t[:, to_index].copy_(cache_t[:, from_index],
+                                       non_blocking=True)
+
+    def _move_out_if_already_occupied(self, index: int,
+                                      all_occupied_indices: List[int]):
+        if index in all_occupied_indices:
+            first_free_index = self._first_free_index_in_mamba_cache()
+            # In case occupied, move the occupied to a new empty block
+            self._move_cache_index_and_mappings(from_index=index,
+                                                to_index=first_free_index)
+
+    def _assign_seq_id_to_mamba_cache_in_specific_dest(self, cur_rid: str,
+                                                       seq_id: int,
+                                                       destination_index: int):
+        """
+        Assign (req_id,seq_id) pair to a `destination_index` index, if
+        already occupied, move the occupying index to a free index.
+        """
+        all_occupied_indices = self._get_all_occupied_indices()
+        if cur_rid not in self.mamba_cache_indices_mapping:
+            self._move_out_if_already_occupied(
+                index=destination_index,
+                all_occupied_indices=all_occupied_indices)
+            self.mamba_cache_indices_mapping[cur_rid] = {
+                seq_id: destination_index
+            }
+        elif seq_id not in (seq_ids2indices :=
+                            self.mamba_cache_indices_mapping[cur_rid]):
+            # parallel sampling , where n > 1, assume prefill have
+            # already happened now we only need to copy the already
+            # existing cache into the siblings seq_ids caches
+            self._move_out_if_already_occupied(
+                index=destination_index,
+                all_occupied_indices=all_occupied_indices)
+            index_exists = list(seq_ids2indices.values())[0]
+            # case of decoding n>1, copy prefill cache to decoding indices
+            self._copy_mamba_cache(from_index=index_exists,
+                                   to_index=destination_index)
+            self.mamba_cache_indices_mapping[cur_rid][
+                seq_id] = destination_index
+        else:
+            # already exists
+            cache_index_already_exists = self.mamba_cache_indices_mapping[
+                cur_rid][seq_id]
+            if cache_index_already_exists != destination_index:
+                # In case the seq id already exists but not in
+                # the right destination, swap it with what's occupying it
+                self._swap_pair_indices_and_mappings(
+                    from_index=cache_index_already_exists,
+                    to_index=destination_index)
+
+    def _prepare_current_run_mamba_cache(
+            self, request_ids_to_seq_ids: Dict[str, list[int]],
+            finished_requests_ids: List[str]):
+        running_indices = []
+        request_ids_to_seq_ids_flatten = [
+            (req_id, seq_id)
+            for req_id, seq_ids in request_ids_to_seq_ids.items()
+            for seq_id in seq_ids
+        ]
+        batch_size = len(request_ids_to_seq_ids_flatten)
+        for dest_index, (request_id,
+                         seq_id) in enumerate(request_ids_to_seq_ids_flatten):
+            if request_id in finished_requests_ids:
+                # Do not allocate cache index for requests that run
+                # and finish right after
+                continue
+            self._assign_seq_id_to_mamba_cache_in_specific_dest(
+                request_id, seq_id, dest_index)
+            running_indices.append(dest_index)
+
+        self._clean_up_first_bs_blocks(batch_size, running_indices)
+        conv_state = self.mamba_cache[0][:, :batch_size]
+        temporal_state = self.mamba_cache[1][:, :batch_size]
+
+        return (conv_state, temporal_state)
+
+    def _get_all_occupied_indices(self):
+        return [
+            cache_idx
+            for seq_ids2indices in self.mamba_cache_indices_mapping.values()
+            for cache_idx in seq_ids2indices.values()
+        ]
+
+    def _clean_up_first_bs_blocks(self, batch_size: int,
+                                  indices_for_current_run: List[int]):
+        # move out all of the occupied but currently not running blocks
+        # outside of the first n blocks
+        destination_indices = range(batch_size)
+        max_possible_batch_size = self.mamba_cache[0].shape[1]
+        for destination_index in destination_indices:
+            if destination_index in self._get_all_occupied_indices() and  \
+               destination_index not in indices_for_current_run:
+                # move not running indices outside of the batch
+                all_other_indices = list(
+                    range(batch_size, max_possible_batch_size))
+                first_avail_index = self._first_free_index_in_mamba_cache(
+                    all_other_indices)
+                self._swap_indices(from_index=destination_index,
+                                   to_index=first_avail_index)
+
+    def _move_cache_index_and_mappings(self, from_index: int, to_index: int):
+        self._copy_mamba_cache(from_index=from_index, to_index=to_index)
+        self._update_mapping_index(from_index=from_index, to_index=to_index)
+
+    def _swap_pair_indices_and_mappings(self, from_index: int, to_index: int):
+        self._swap_mamba_cache(from_index=from_index, to_index=to_index)
+        self._swap_mapping_index(from_index=from_index, to_index=to_index)
+
+    def _swap_mapping_index(self, from_index: int, to_index: int):
+        for seq_ids2index in self.mamba_cache_indices_mapping.values():
+            for seq_id, index in seq_ids2index.items():
+                if from_index == index:
+                    seq_ids2index.update({seq_id: to_index})
+                elif to_index == index:
+                    seq_ids2index.update({seq_id: from_index})
+
+    def _update_mapping_index(self, from_index: int, to_index: int):
+        for seq_ids2index in self.mamba_cache_indices_mapping.values():
+            for seq_id, index in seq_ids2index.items():
+                if from_index == index:
+                    seq_ids2index.update({seq_id: to_index})
+                    return
+
+    def _release_finished_requests(self,
+                                   finished_seq_groups_req_ids: List[str]):
+        for req_id in finished_seq_groups_req_ids:
+            if req_id in self.mamba_cache_indices_mapping:
+                self.mamba_cache_indices_mapping.pop(req_id)
+
+    def _first_free_index_in_mamba_cache(
+            self, indices_range: Optional[List[int]] = None) -> int:
+        assert self.mamba_cache is not None
+        if indices_range is None:
+            max_possible_batch_size = self.mamba_cache[0].shape[1]
+            indices_range = list(range(max_possible_batch_size))
+        all_occupied_indices = self._get_all_occupied_indices()
+        for i in indices_range:
+            if i not in all_occupied_indices:
+                return i
+        raise Exception("Couldn't find a free spot in the mamba cache! This"
+                        "should never happen")