diff --git a/colossalai/inference/batch_bucket.py b/colossalai/inference/batch_bucket.py
new file mode 100644
index 000000000..93d4c2004
--- /dev/null
+++ b/colossalai/inference/batch_bucket.py
@@ -0,0 +1,449 @@
+from typing import Callable, List, Optional, Tuple, Union
+
+import torch
+
+from colossalai.inference.struct import Sequence
+from colossalai.utils import get_current_device
+
+
+class BatchBucket:
+    """Container for a batch of Sequences, which is used to manage the batch of sequences.
+
+    Attrs:
+        _sequences_dict (Dict[int, Sequence]): Map sequence uid to sequence struct
+            seq_uid -> Sequence
+        _sequences_indexes (Dict[int, int]): Map sequence uid to index in the batch
+            seq_uid -> index in the batch (indexing used in sequence_lengths and block_tables)
+        _sequence_lengths (torch.Tensor): Length of each sequence in the batch.
+            The size of the tensor is (max_batch_size,)
+        _block_tables (torch.Tensor): Block table of each sequence in the batch
+            The size of the tensor is (max_batch_size, max_blocks_per_seq)
+    """
+
+    def __init__(
+        self,
+        num_heads,
+        head_dim,
+        max_batch_size,
+        max_length,
+        block_size,
+        kv_max_split_num,
+        fd_interm_tensor=None,
+        device=None,
+        dtype=torch.float16,
+    ):
+        self.num_heads = num_heads
+        self.head_dim = head_dim
+        self.max_batch_size = max_batch_size
+        self.max_length = max_length  # in + out len
+        self.block_size = block_size
+        self.kv_max_split_num = kv_max_split_num  # Hint used for flash decoding
+        self.fd_interm_tensor = fd_interm_tensor
+        self.device = device or get_current_device()
+        self.dtype = dtype
+
+        self._current_batch_size = 0
+        self._sequences_dict = dict()
+        self._sequences_indexes = dict()  # deque(maxlen=self.max_batch_size)
+        self._sequence_lengths = torch.zeros((self.max_batch_size,), dtype=torch.int32)
+        self._sequence_lengths_helper = torch.zeros_like(self._sequence_lengths)
+        max_blocks_per_seq = (self.max_length + block_size - 1) // block_size
+        self._block_tables = torch.full((self.max_batch_size, max_blocks_per_seq), -1, dtype=torch.int32)
+        self._block_tables_helper = torch.full_like(self._block_tables, -1)
+
+    @property
+    def is_empty(self):
+        return self._current_batch_size == 0
+
+    @property
+    def current_batch_size(self):
+        return self._current_batch_size
+
+    @property
+    def available_batch_size(self):
+        return self.max_batch_size - self._current_batch_size
+
+    @property
+    def block_tables(self):
+        return self._block_tables
+
+    @property
+    def seq_lengths(self):
+        return self._sequence_lengths
+
+    @property
+    def seqs_ids(self):
+        return list(self._sequences_dict.keys())
+
+    @property
+    def seqs_li(self):
+        return list(self._sequences_dict.values())
+
+    @property
+    def is_compact(self):
+        assert len(self._sequences_dict) == len(self._sequences_indexes), "BatchBucket indexing is not consistent"
+        return (
+            len(self._sequences_dict)
+            == torch.nonzero(self._sequence_lengths).view(-1).numel()
+            == torch.nonzero(self._block_tables[:, 0] >= 0).numel()
+        )
+
+    def _make_compact(self) -> None:
+        # Clean and Compress the batch based on its sequences dict.
+        # Namely,compress sequences to the front and clean the seq lengths and block tables tensors.
+        # NOTE Prevent calling this method multiple times in a single step
+        if self.is_compact:
+            return
+        valid_seq_ids = self._sequences_dict.keys()
+        valid_num = len(valid_seq_ids)
+        valid_indexes = [self._sequences_indexes[seq_id] for seq_id in valid_seq_ids]
+        assert valid_num == len(self._sequences_indexes), "BatchBucket indexing is not consistent"
+        self._sequence_lengths_helper[:valid_num] = self._sequence_lengths[valid_indexes]
+        self._sequence_lengths[:] = self._sequence_lengths_helper[:]
+        self._block_tables_helper[:valid_num, :] = self.block_tables[valid_indexes]
+        self.block_tables[:] = self._block_tables_helper[:]
+        new_idx = 0
+        for seq_id in valid_seq_ids:
+            self._sequences_indexes[seq_id] = new_idx
+            new_idx += 1
+        self._sequence_lengths_helper.fill_(0)
+        self._block_tables_helper.fill_(-1)
+        self._current_batch_size = valid_num
+
+    def add_seq(
+        self,
+        seq: Sequence,
+        alloc_block_table: torch.Tensor = None,
+        alloc_block_table_fn: Callable[[torch.Tensor, int], None] = None,
+    ) -> Union[torch.Tensor, None]:
+        """Add a single sequence to the batch.
+        User could opt to provide either a block table or a function to allocate block tables.
+
+        Args:
+            seq (Sequence): The sequence to be added to the batch
+            alloc_block_table (torch.Tensor): The block tables to be copied and used for the sequence
+            alloc_block_table_fn (Callable[[torch.Tensor, int], None]): The function to allocate blocks for the sequence,
+                which is expected to reserve blocks and update status of kv-cache manager.
+
+        Returns:
+            block_table (torch.Tensor): The block table of the added sequence, used for block allocation in kv-cache manager.
+                None if the sequence cannot be added.
+        """
+        block_table = None
+        # TODO might consider sorting by length
+        if self._current_batch_size < self.max_batch_size:
+            self._sequences_dict[seq.request_id] = seq
+            self._sequences_indexes[seq.request_id] = self._current_batch_size
+            self._sequence_lengths[self._current_batch_size] = seq.sentence_len
+            # NOTE the added seq still require block table allocation by kvcache manager
+            block_table = self._block_tables[self._current_batch_size - 1]
+            if alloc_block_table is not None:
+                # copy block ids from provided block tables
+                self._block_tables[self._current_batch_size - 1] = alloc_block_table
+            elif alloc_block_table_fn:
+                alloc_block_table_fn(block_table, self._sequence_lengths[self._current_batch_size - 1].item())
+            self._current_batch_size += 1
+        return block_table
+
+    def add_seqs(
+        self,
+        seqs: List[Sequence],
+        alloc_block_tables: torch.Tensor = None,
+        alloc_block_tables_fn: Callable[[torch.Tensor, torch.Tensor], None] = None,
+    ) -> Union[torch.Tensor, None]:
+        """Add a list of sequences to the batch.
+        User could opt to provide either block tables or a function to allocate block tables.
+
+        Args:
+            seqs (List[Sequence]): The sequences to be added to the batch
+            alloc_block_tables (torch.Tensor): The block tables to be copied and used for the sequence
+            alloc_block_table_fn (Callable[[torch.Tensor, torch.Tensor], None]): The function to allocate blocks for multiple sequences,
+                which is expected to reserve blocks and update status of kv-cache manager.
+
+        Returns:
+            block_tables (torch.Tensor): The block tables of the added sequences, used for block allocation in kv-cache manager.
+                None if the sequences cannot be added.
+        """
+
+        assert (
+            alloc_block_tables is None or alloc_block_tables_fn is None
+        ), "`alloc_block_tables` and `alloc_block_tables_fn` cannot be provided at the same time"
+
+        num_seqs_to_add = min(self.max_batch_size - self._current_batch_size, len(seqs))
+        block_tables = None
+        if num_seqs_to_add > 0:
+            for i, seq in enumerate(seqs[:num_seqs_to_add]):
+                self._sequences_dict[seq.request_id] = seq
+                self._sequences_indexes[seq.request_id] = self._current_batch_size + i
+            # TODO external (rename): modify Sequence.sentence_len to seq_len
+            self._sequence_lengths[
+                self._current_batch_size : self._current_batch_size + num_seqs_to_add
+            ] = torch.tensor([seq.sentence_len for seq in seqs[:num_seqs_to_add]], dtype=torch.int32)
+            # NOTE block tables to be updated by kvcache manager
+            block_tables = self._block_tables[self._current_batch_size : self._current_batch_size + num_seqs_to_add]
+            if alloc_block_tables is not None:
+                # copy block ids from provided block tables
+                self._block_tables[
+                    self._current_batch_size : self._current_batch_size + num_seqs_to_add
+                ] = alloc_block_tables
+            elif alloc_block_tables_fn:
+                alloc_block_tables_fn(
+                    block_tables,
+                    self._sequence_lengths[self._current_batch_size : self._current_batch_size + num_seqs_to_add],
+                )
+
+            self._current_batch_size += num_seqs_to_add
+            seqs[:] = seqs[num_seqs_to_add:]
+
+        return block_tables
+
+    def pop_seq_update_batch(
+        self, request_id: int, free_block_table_fn: Callable[[torch.Tensor], None] = None
+    ) -> Tuple[Sequence, Union[torch.Tensor, None]]:
+        """Pop a single sequence by id from the batch, and update the batch bucket status.
+
+        Args:
+            request_id (int): The uid of the sequence
+            free_block_table_fn (Callable): The function to free the block table of a sequence,
+                if not provided, then we have to release the block table manually after calling this method
+
+        Returns:
+            A tuple of: seq (Sequence): The target sequence
+            and block_table (torch.Tensor): block table of the target sequence indicating corresponding blocks,
+                none if the sequence is not found or free_block_table_fn is provided.
+        """
+        seq: Sequence = self._sequences_dict.get(request_id)
+        block_table = None
+        if seq is not None:
+            assert request_id in self._sequences_indexes, "Inconsistency in BatchBucket indexing"
+            self._sequences_dict.pop(request_id)
+            seq_b_idx = self._sequences_indexes.get(request_id)
+
+            if self.current_batch_size > 1:
+                # replace seq length of the target seq with that of the last seq in the batch
+                last_seq_b_idx = self.current_batch_size - 1
+                last_seq_id = next(
+                    (uid for uid, index in self._sequences_indexes.items() if index == last_seq_b_idx),
+                    None,
+                )
+                assert last_seq_id is not None
+                self._sequences_indexes[last_seq_id] = seq_b_idx
+                self._sequence_lengths[seq_b_idx] = self._sequence_lengths[last_seq_b_idx]
+                self._sequence_lengths[last_seq_b_idx].fill_(0)
+                # free the block table of the seq, or return a copy of the block table (to be processed outside)
+                if free_block_table_fn:
+                    free_block_table_fn(self._block_tables[seq_b_idx])
+                else:
+                    block_table = self._block_tables[seq_b_idx].detach().clone()
+                # replace block table of the target seq with that of the last seq in the batch
+                self._block_tables[seq_b_idx] = self._block_tables[last_seq_b_idx]
+                self._block_tables[last_seq_b_idx].fill_(-1)
+            else:
+                if free_block_table_fn:
+                    free_block_table_fn(self._block_tables[0])
+                else:
+                    block_table = self._block_tables[0].detach().clone()
+                self._sequence_lengths[0].fill_(0)
+                self._block_tables[0].fill_(-1)
+            self._sequences_indexes.pop(request_id)
+            self._current_batch_size -= 1
+
+        return seq, block_table
+
+    def pop_seqs(
+        self, request_ids: List[int], free_block_table_fn: Callable[[torch.Tensor], None] = None
+    ) -> Tuple[List[Sequence], List[torch.Tensor]]:
+        """Iteratively pop a list of sequences by uid.
+
+        Args:
+            request_ids (List[int]): The uids of the sequences
+            free_block_table_fn (Callable): The function to free the block table of a sequence,
+                if not provided, then we have to release the block table manually after calling this method
+        Returns:
+            A tuple of: seqs (List[Sequence]): The target sequences
+            and block_tables (List[torch.Tensor]): block tables of the target sequences indicating corresponding blocks
+        """
+        seqs = []
+        block_tables = []
+        for request_id in request_ids:
+            seq, block_table = self.pop_seq_update_batch(request_id, free_block_table_fn)
+            if seq is not None:
+                seqs.append(seq)
+            if block_table is not None:
+                block_tables.append(block_table)
+        return seqs, block_tables
+
+    def pop_n_seqs(
+        self, n: int, free_block_table_fn: Callable[[torch.Tensor], None] = None
+    ) -> Tuple[List[Sequence], List[torch.Tensor]]:
+        """Pop the first n sequences in the batch (FIFO).
+        If n is greater than the current batch szie, pop all the sequences in the batch.
+
+        Args:
+            n (int): The number of sequences to pop out
+            free_block_table_fn (Callable): The function to free the block table of a single sequence
+        Returns:
+            A tuple of: seqs (List[Sequence]): The target sequences,
+            and block_tables (List[torch.Tensor]): block tables of the target sequences indicating corresponding blocks
+        """
+        # NOTE Prevent calling this method multiple times in a single step
+        seqs = []
+        block_tables = []
+        n = min(n, self.current_batch_size)
+        seq_ids = list(self._sequences_dict.keys())[:n]
+        for seq_id in seq_ids:
+            seq = self._sequences_dict.pop(seq_id)
+            seq_b_idx = self._sequences_indexes.pop(seq_id)
+            if free_block_table_fn:
+                free_block_table_fn(self.block_tables[seq_b_idx])
+            else:
+                block_tables.append(self.block_tables[seq_b_idx].detach().clone())
+            seqs.append(seq)
+        if not self.is_compact:
+            self._make_compact()
+        return seqs, block_tables
+
+    def pop_finished(
+        self, free_block_table_fn: Callable[[torch.Tensor], None] = None
+    ) -> Tuple[List[Sequence], List[torch.Tensor]]:
+        """Pop finished sequences in the batch and a list of block tables of the finished sequences,
+        if free_block_table_fn is not provided.
+
+        Args:
+            free_block_table_fn (Callable): The function to free the block table of a single sequence
+        Returns:
+            A tuple of: finished_seqs (List[Sequence]): The finished sequences,
+            and finished_block_tables (List[torch.Tensor]): block tables of the finished sequences.
+        """
+        finished_seqs = []
+        finished_block_tables = []
+        for seq in self._sequences_dict.values():
+            if seq.check_finish():
+                finished_seqs.append(seq)
+        # Use `pop_seq_update_batch`` to update the batch status for just a few of finished seqs,
+        # otherwise, pop seqs directly and then call `_make_compact` to compress the batch.
+        # For now, the performance difference is not significant, so we use the frist method to pop seqs.
+        # Precise evaluations to be done.
+        for seq in finished_seqs:
+            _, block_table = self.pop_seq_update_batch(seq.request_id, free_block_table_fn)
+            if block_table is not None:
+                finished_block_tables.append(block_table)
+
+        return finished_seqs, finished_block_tables
+
+    # TODO arg type not support beam search sampling yet
+    def append_batch_tokens(self, tokens: torch.Tensor) -> None:
+        """Append a batch of tokens to the sequences in the batch"""
+        assert self.current_batch_size == tokens.size(0), "Batch size mismatch"
+
+        if self.current_batch_size > 0:
+            tokens = tokens.tolist()
+            for seq_id, seq in self._sequences_dict.items():
+                index_in_b = self._sequences_indexes[seq_id]
+                curr_tokens = tokens[index_in_b]
+                if not isinstance(curr_tokens, list):
+                    curr_tokens = [curr_tokens]
+                seq.output_token_id += curr_tokens
+                seq.check_finish()
+            self._sequence_lengths[: self.current_batch_size] += 1
+
+    def clear(self, free_block_tables_fn: Optional[Callable[[torch.Tensor], None]]) -> List[int]:
+        """Clear all the sequences in the batch.
+
+        free_block_tables_fn (Optional[Callable]): The function to free the block tables of all the sequences in a batch
+        """
+        seqs = list(self._sequences_dict.values())
+        self._sequences_dict.clear()
+        self._sequences_indexes.clear()
+        if free_block_tables_fn:
+            free_block_tables_fn(self.block_tables, self._current_batch_size)
+        self._block_tables.fill_(-1)
+        self._sequence_lengths.fill_(0)
+        self._current_batch_size = 0
+        return seqs
+
+    def merge(self, other: "BatchBucket") -> List[int]:
+        """Merge the sequences in the other batch into the current batch.
+        Merge as possible as the current batch can, if it does not have available spaces
+        holding all the sequences in the other batch
+
+        Usage:
+            > New incoming sequence added to prefil batch
+                prefill bb curr batch size < prefil_ratio * prefill bb max batch size
+            > New incoming sequence added to prefil batch
+                prefill bb curr batch size == prefil_ratio * prefill bb max batch size
+            > Pause Decoding
+            > Prefill
+            > Move sequences in prefill bb => decoding bb
+            > Put back the out-of-volume sequences into the running pool
+
+        Returns:
+            unmerged_ids (List[int]): a list of sequence uids that are not merged into the current batch
+        """
+        unmerged_ids = []
+        num_seqs_to_merge = min(self.available_batch_size, other.current_batch_size)
+        if num_seqs_to_merge > 0:
+            seqs, block_tables_li = other.pop_n_seqs(num_seqs_to_merge)
+            block_tables = torch.stack(block_tables_li)
+            self.add_seqs(seqs, alloc_block_tables=block_tables)
+            unmerged_ids = other.seqs_ids
+        return unmerged_ids
+
+    ########## The following methods are expected to be used in modeling ###########
+
+    # For compatibility.
+    # NOTE: This is an assumption way to determine the stage of the batch.
+    @property
+    def is_prompts(self) -> bool:
+        assert len(self._sequences_dict) > 0, "No sequence in the batch"
+        first_seq = next(iter(self._sequences_dict.values()))
+        if first_seq.output_len == 0:
+            return True
+        return False
+
+    # For compatibility
+    def get_1D_inputs(self) -> torch.Tensor:
+        assert len(self._sequences_dict) > 0, "No sequence in the batch"
+        first_seq = next(iter(self._sequences_dict.values()))  # not exactly the first sequence
+        if first_seq.output_len == 0:
+            # Assume prefill stage
+            assert all(
+                seq.output_len == 0 for seq in self._sequences_dict.values()
+            ), "Sequence stage (Prefill/Decoding) must be the same in the batch"
+            out_li = []
+            num_tokens = torch.sum(self._sequence_lengths)
+            out = torch.empty([num_tokens], dtype=torch.long)
+            seq_ids = sorted(self._sequences_indexes.keys(), key=lambda x: self._sequences_indexes[x])
+            for seq_id in seq_ids:
+                seq: Sequence = self._sequences_dict[seq_id]
+                out_li.extend(seq.input_token_id)
+            return torch.tensor(out_li, dtype=torch.long, device=self.device)
+        else:
+            # Assume decoding stage
+            assert all(
+                seq.output_len > 0 for seq in self._sequences_dict.values()
+            ), "Sequence stage (Prefill/Decoding) must be the same in the batch"
+            assert self.is_compact, "BatchBucket is not compact"
+            out = torch.empty([self.current_batch_size], dtype=torch.long)
+            for seq_id, index_in_b in self._sequences_indexes.items():
+                seq: Sequence = self._sequences_dict[seq_id]
+                out[index_in_b] = seq.output_token_id[-1]
+            return out.to(device=self.device)
+
+    # For compatibility
+    def get_block_table_tensor(self) -> torch.Tensor:
+        assert self.is_compact  # Debug usage
+        block_table = self.block_tables[: self.current_batch_size]
+        return block_table.to(device=self.device)
+
+    # For compatibility
+    def get_sequence_lengths(self) -> torch.Tensor:
+        assert self.is_compact  # Debug usage
+        sequence_lengths = self.seq_lengths[: self.current_batch_size]
+        return sequence_lengths.to(device=self.device)
+
+    # For compatibility
+    @property
+    def fd_inter_tensor(self) -> None:
+        assert self.fd_interm_tensor is not None, "fd_interm_tensor is not provided"
+        return self.fd_interm_tensor
diff --git a/colossalai/inference/config.py b/colossalai/inference/config.py
index a210fbf64..7ce4719e7 100644
--- a/colossalai/inference/config.py
+++ b/colossalai/inference/config.py
@@ -109,7 +109,7 @@ class InferenceConfig:
         ), f"Expected dtype to be in {_ALLOWED_DTYPES} but found an unknown dtype: {self.dtype}"
 
         # check distributed
-        assert (
+        assert (not torch.distributed.is_initialized() and self.tp_size * self.pp_size == 1) or (
             self.tp_size * self.pp_size == dist.get_world_size()
         ), f"TP size({self.tp_size}) * PP size({self.pp_size}) should be equal to the global world size ({dist.get_world_size()})"
         # check prompt template
diff --git a/colossalai/inference/core/engine.py b/colossalai/inference/core/engine.py
index bd078dbd5..ea2e341d4 100644
--- a/colossalai/inference/core/engine.py
+++ b/colossalai/inference/core/engine.py
@@ -42,7 +42,7 @@ class InferenceEngine:
     def __init__(
         self,
         model: nn.Module,
-        tokenizer: [Union[PreTrainedTokenizer, PreTrainedTokenizerFast]],
+        tokenizer: Union[PreTrainedTokenizer, PreTrainedTokenizerFast],
         inference_config: InferenceConfig,
         verbose: bool = False,
         model_policy: Policy = None,
@@ -254,20 +254,12 @@ class InferenceEngine:
             else:
                 prompt = prompts[i]
 
-            max_blocks_per_sequence = (
-                self.inference_config.max_input_len
-                + self.inference_config.max_output_len
-                + self.inference_config.block_size
-                - 1
-            ) // self.inference_config.block_size
-            block_table = torch.full([max_blocks_per_sequence], -1, device=self.device)
             sequence = Sequence(
                 request_id,
                 prompt,
                 prompts_token_ids[i],
                 block_size,
                 None,
-                block_table,
                 self.tokenizer.eos_token_id,
                 self.tokenizer.pad_token_id,
                 self.inference_config.max_output_len,
diff --git a/colossalai/inference/core/request_handler.py b/colossalai/inference/core/request_handler.py
index 7e66cfe31..a331e9cf8 100644
--- a/colossalai/inference/core/request_handler.py
+++ b/colossalai/inference/core/request_handler.py
@@ -1,15 +1,16 @@
-from typing import List
+from typing import Dict, List, Union
 
 import torch
 from transformers.configuration_utils import PretrainedConfig
 from transformers.generation import GenerationConfig
 
+from colossalai.inference.batch_bucket import BatchBucket
 from colossalai.inference.config import InferenceConfig
 from colossalai.inference.flash_decoding_utils import FDIntermTensors
 from colossalai.inference.kv_cache import KVCacheManager
 from colossalai.inference.logit_processors import logit_processor
 from colossalai.inference.sampler import *
-from colossalai.inference.struct import BatchInfo, RequestStatus, Sequence
+from colossalai.inference.struct import RequestStatus, Sequence
 from colossalai.logging import get_dist_logger
 
 __all__ = ["RunningList", "RequestHandler"]
@@ -24,45 +25,79 @@ class RunningList:
 
     Args:
         prefill_ratio: (float) A ratio for determing whether to perform prefill or not.
-        prefill: (List) List that contains default inputs, defaults to [].
+        _prefill (OrderedDict[Sequence]): Mapping of sequence uid -> Sequence.
+        _decoding (OrderedDict[Sequence]): Mapping of sequence uid -> Sequence.
     """
 
-    def __init__(self, prefill_ratio: str, prefill: List[Sequence] = None):
+    def __init__(self, prefill_ratio: int, prefill: List[Sequence] = None) -> None:
         self.prefill_ratio = prefill_ratio
-        self.decoding: List[Sequence] = []
-        self.prefill: List[Sequence] = prefill if prefill is not None else []
+        self._decoding: Dict[int, Sequence] = dict()
+        self._prefill: Dict[int, Sequence] = (
+            dict({seq.request_id: seq for seq in self._prefill}) if prefill is not None else dict()
+        )
 
-    def append(self, seq: Sequence):
-        # add seq to prefilling list first.
-        self.prefill.append(seq)
-
-    def find_seq(self, request_id):
-        for seq in self.decoding:
-            if request_id == seq.request_id:
-                return seq
-        for seq in self.prefill:
-            if request_id == seq.request_id:
-                return seq
-        return None
+    @property
+    def decoding(self):
+        return list(self._decoding.values())
+
+    @property
+    def prefill(self):
+        return list(self._prefill.values())
+
+    @property
+    def prefill_seq_num(self):
+        return len(self._prefill)
+
+    @property
+    def decoding_seq_num(self):
+        return len(self._decoding)
+
+    @property
+    def total_seq_num(self):
+        return self.prefill_seq_num + self.decoding_seq_num
 
-    def remove(self, seq: Sequence):
-        if seq in self.decoding:
-            self.decoding.remove(seq)
-        elif seq in self.prefill:
-            self.prefill.remove(seq)
+    def append(self, seq: Sequence):
+        assert (seq.request_id not in self._prefill) and (
+            seq.request_id not in self._decoding
+        ), f"Sequence uid {seq.request_id} already exists."
+        self._prefill[seq.request_id] = seq
+
+    def extend(self, seqs: List[Sequence]):
+        for seq in seqs:
+            self._prefill[seq.request_id] = seq
+
+    def find_seq(self, request_id) -> Union[Sequence, None]:
+        seq = None
+        if request_id in self._decoding:
+            seq = self._decoding[request_id]
+        elif request_id in self._prefill:
+            seq = self._prefill[request_id]
+        return seq
+
+    def remove(self, seq: Sequence) -> None:
+        if seq.request_id in self._decoding:
+            self._decoding.pop(seq.request_id)
+        elif seq.request_id in self._prefill:
+            self._prefill.pop(seq.request_id)
         else:
-            raise ValueError(f"sequence {seq.request_id} is not in running list")
+            raise ValueError(f"Sequence {seq.request_id} is not in running list")
 
     def ready_for_prefill(self):
-        if not self.decoding:
-            return len(self.prefill) > 0
-        return len(self.prefill) / len(self.decoding) >= self.prefill_ratio
+        if not self._decoding:
+            return len(self._prefill) > 0
+        return len(self._prefill) / len(self._decoding) >= self.prefill_ratio
 
     def is_empty(self):
-        return not self.decoding and not self.prefill
+        return not self._decoding and not self._prefill
 
-    def total_seq_num(self):
-        return len(self.decoding) + len(self.prefill)
+    def mark_prefill_running(self) -> None:
+        for seq_id in self._prefill:
+            self._prefill[seq_id].mark_running()
+
+    def move_prefill_to_decoding(self, seq_ids: List[int]) -> None:
+        for seq_id in seq_ids:
+            assert seq_id in self._prefill, f"Sequence {seq_id} is not in prefill list"
+            self._decoding[seq_id] = self._prefill.pop(seq_id)
 
 
 class RequestHandler:
@@ -110,25 +145,27 @@ class RequestHandler:
 
         # TODO In the continuous batching scenario, the batch size may be greater than max_batch_size,
         # which may cause bugs and this issue should be fixed later.
-        self.running_batch = BatchInfo(
-            max_batch_size=self.max_batch_size,
-            kv_max_split_num=kv_max_split_num,
+        self.running_bb = BatchBucket(
             num_heads=model_config.num_attention_heads,
             head_dim=head_dim,
-            is_prompts=False,
-            device=device,
-            dtype=self.dtype,
-            fd_inter_tensor=fd_inter_tensor,
-        )
-        self.prefill_batch = BatchInfo(
             max_batch_size=self.max_batch_size,
+            max_length=inference_config.max_input_len + inference_config.max_output_len,
+            block_size=inference_config.block_size,
             kv_max_split_num=kv_max_split_num,
+            fd_interm_tensor=fd_inter_tensor,
+            dtype=self.dtype,
+            device=device,
+        )
+        self.prefill_bb = BatchBucket(
             num_heads=model_config.num_attention_heads,
             head_dim=head_dim,
-            is_prompts=True,
-            device=device,
+            max_batch_size=self.max_batch_size,
+            max_length=inference_config.max_input_len + inference_config.max_output_len,
+            block_size=inference_config.block_size,
+            kv_max_split_num=kv_max_split_num,
+            fd_interm_tensor=fd_inter_tensor,
             dtype=self.dtype,
-            fd_inter_tensor=fd_inter_tensor,
+            device=device,
         )
 
     def _init_cache(self, model_config):
@@ -159,40 +196,39 @@ class RequestHandler:
                             remove_list.append(seq)
                             break
 
-                        # stop feeding new sequence into running list to assure
-                        if self.cache_manager.num_available_blocks <= self.running_list.total_seq_num():
-                            break
+                    num_seqs_to_add = min(len(lst), self.max_batch_size - self.running_list.total_seq_num)
+                    remove_list.extend(lst[:num_seqs_to_add])
+                    self.running_list.extend(lst[:num_seqs_to_add])
 
-                        # Try to allocate cache blocks for the sequence.
-                        if (
-                            self.cache_manager.check_allocation(seq)
-                            and (len(self.running_list.prefill) + len(self.running_list.decoding))
-                            < self.max_batch_size  # There some bugs in continous batching, so we disable it here.
-                        ):
-                            # If succeed, add the sequence to running list.
-                            remove_list.append(seq)
-                            self.running_list.append(seq)
-                            self.cache_manager.allocate_context_from_block_table(seq.block_table, seq.sentence_len)
                     for seq in remove_list:
                         lst.remove(seq)
 
         if self.running_list.ready_for_prefill():
-            for seq in self.running_list.prefill:
-                seq.mark_running()
-            self.prefill_batch.add_seqs(self.running_list.prefill)
-            return self.prefill_batch
+            num_seqs_to_add = min(self.running_list.prefill_seq_num, self.running_bb.available_batch_size)
 
-        if not self.running_batch.is_empty:
-            for seq in self.running_batch.sequences_set:
-                recycle = self.cache_manager.allocate_token_from_block_table(seq.block_table, seq.sentence_len)
-                if recycle:
+            for seq in self.running_list.prefill[:num_seqs_to_add]:
+                seq.mark_running()
+            # allocate blocks for the prefill batch
+            self.prefill_bb.add_seqs(
+                self.running_list.prefill[:num_seqs_to_add],
+                alloc_block_tables_fn=self.cache_manager.allocate_context_from_block_tables,
+            )
+
+            return self.prefill_bb
+
+        if not self.running_bb.is_empty:
+            seqs_ids_to_recycle = self.cache_manager.allocate_tokens_from_block_tables(
+                self.running_bb.block_tables, self.running_bb.seq_lengths, self.running_bb.current_batch_size
+            )
+            if seqs_ids_to_recycle:
+                seqs_to_recycle = self.running_bb.pop_seqs(seqs_ids_to_recycle)
+                for seq in seqs_to_recycle:
                     seq.recycle()
-                    self.running_batch.del_seq(seq)
                     self.running_list.remove(seq)
                     self.waiting_list[-1].append(seq)
                     # the recycled sequences are handled with highest priority.
 
-        return self.running_batch
+        return self.running_bb
 
     def add_sequence(self, req: Sequence):
         """
@@ -213,7 +249,7 @@ class RequestHandler:
             seq.mark_aborted()
             self.waiting_list[priority].remove(seq)
         elif seq.status.is_running():
-            self.cache_manager.free_block_table(seq.block_table)
+            self.running_bb.pop_seq_update_batch(seq.request_id, self.cache_manager.free_block_table)
             self.running_list.remove(seq)
         else:
             try:
@@ -242,7 +278,7 @@ class RequestHandler:
             else:
                 sample_tokens = greedy_sample(generation_config, logprobs)
         else:
-            sample_tokens = beam_search_sample(generation_config, logprobs, is_prompt=not self.prefill_batch.is_empty)
+            sample_tokens = beam_search_sample(generation_config, logprobs, is_prompt=not self.prefill_bb.is_empty)
 
         return sample_tokens
 
@@ -273,27 +309,25 @@ class RequestHandler:
 
         # sample the next tokens
         sample_tokens = self._sample(probs, logprobs, generation_config)
-        if not self.prefill_batch.is_empty:
-            self.prefill_batch.update_batch_tokens(sample_tokens)
+        if not self.prefill_bb.is_empty:
+            self.prefill_bb.append_batch_tokens(sample_tokens)
         else:
-            self.running_batch.update_batch_tokens(sample_tokens)
+            self.running_bb.append_batch_tokens(sample_tokens)
 
     def update(self):
         """
         Update current running list and done list
         """
-        if not self.prefill_batch.is_empty:
-            self.running_list.decoding.extend(self.running_list.prefill)
-            self.running_batch.add_seqs(self.running_list.prefill)
-            self.running_list.prefill.clear()
-            self.prefill_batch.clear_batch()
-
-        finish_seqs = self.running_batch.fliter_batch()
-
-        for seq in finish_seqs:
+        if not self.prefill_bb.is_empty:
+            self.running_list.move_prefill_to_decoding(self.prefill_bb.seqs_ids)
+            self.running_bb.merge(self.prefill_bb)
+            # clear the prefill batch without assigning a free_block_tables_fn
+            # since we want to reuse the memory recorded on the block tables
+            self.prefill_bb.clear(free_block_tables_fn=None)
+
+        finished_seqs, _ = self.running_bb.pop_finished(self.cache_manager.free_block_table)
+        for seq in finished_seqs:
             self.running_list.remove(seq)
-            self.cache_manager.free_block_table(seq.block_table)
-
-        self.done_list.extend(finish_seqs)
+        self.done_list.extend(finished_seqs)
 
-        return finish_seqs
+        return finished_seqs
diff --git a/colossalai/inference/kv_cache/kvcache_manager.py b/colossalai/inference/kv_cache/kvcache_manager.py
index d16ced8e9..7d435d59c 100644
--- a/colossalai/inference/kv_cache/kvcache_manager.py
+++ b/colossalai/inference/kv_cache/kvcache_manager.py
@@ -63,7 +63,6 @@ class KVCacheManager:
         self.dtype = config.dtype
         self.elem_size_in_bytes = torch.tensor([], dtype=self.dtype).element_size()
         self.num_layers = get_model_config_attr(model_config, "num_hidden_layers")
-        # For now we focus on MHA only, TODO add handling for MQA and GQA
         self.head_num = get_model_config_attr(model_config, "num_attention_heads")
         self.head_size = get_model_config_attr(model_config, "hidden_size") // self.head_num
         assert self.head_num % self.tp_size == 0, f"Cannot shard {self.head_num} heads with tp size {self.tp_size}"
@@ -82,8 +81,8 @@ class KVCacheManager:
 
         # Physical cache allocation
         alloc_shape = (self.num_blocks, self.head_num, self.block_size, self.head_size)
-        if verbose:
-            self.logger.info(f"Allocating KV cache with shape: {alloc_shape} consisting of {self.num_blocks} blocks.")
+        # if verbose:
+        #     self.logger.info(f"Allocating KV cache with shape: {alloc_shape} consisting of {self.num_blocks} blocks.")
         self._kv_caches = self._init_device_caches(alloc_shape)
         self.total_physical_cache_size_in_bytes = (
             self.elem_size_in_bytes
@@ -112,6 +111,9 @@ class KVCacheManager:
         """Get the number of available cache blocks."""
         return self._available_blocks
 
+    def get_head_size(self):
+        return self.head_size
+
     def get_kv_cache(self):
         """Get k_cache and v_cache"""
         return self._kv_caches
@@ -148,7 +150,7 @@ class KVCacheManager:
         and updates the provided block table with the allocated block ids.
 
         Args:
-            block_table: A 1D tensor of shape [max_blocks_per_sequence] holded by a sequence, storing mapping of token_position_id -> block_id.
+            block_table: A 1D tensor of shape [max_blocks_per_sequence], mapping of token_position_id -> block_id.
             context_len: The length of the processing sequnece.
         """
         assert block_table.dim() == 1
@@ -193,12 +195,85 @@ class KVCacheManager:
             else:
                 self._allocate_on_block(block, block.block_size)
 
+    def allocate_context_from_block_tables(self, block_tables: torch.Tensor, context_lengths: torch.Tensor) -> None:
+        """Allocate logical cache blocks for a batch of sequences during prefill stage.
+
+        Args:
+            block_tables (torch.Tensor): [bsz, max_blocks_per_sequence]
+            context_lengths (torch.Tensor): [bsz]]
+        """
+        assert block_tables.dim() == 2
+        assert block_tables.size(0) == context_lengths.size(0)
+        if not torch.all(block_tables < 0):
+            self.logger.error("Some slots on provided block table have been allocated.")
+        blocks_required = (context_lengths + self.block_size - 1) // self.block_size
+        num_blocks_required = torch.sum(blocks_required).item()
+        assert isinstance(num_blocks_required, int)
+        if num_blocks_required > self._available_blocks:
+            self.logger.warning(
+                f"Lacking blocks to allocate. Available blocks {self._available_blocks}; blocks asked {num_blocks_required}."
+            )
+            return
+
+        bsz = block_tables.size(0)
+        # Try contiguous allocation
+        torch.cumsum(self._block_states, dim=-1, out=self._block_states_cum[1:])
+        torch.subtract(
+            self._block_states_cum[num_blocks_required:],
+            self._block_states_cum[:-num_blocks_required],
+            out=self._block_finder[num_blocks_required - 1 :],
+        )
+        end_indexes = torch.nonzero(self._block_finder == num_blocks_required, as_tuple=False).view(-1)
+        if end_indexes.numel() > 0:
+            # contiguous cache exists
+            end_idx = end_indexes[0].item() + 1  # open interval
+            start_idx = end_idx - num_blocks_required  # closed interval
+            alloc_block_ids = torch.arange(start_idx, end_idx)
+            for i in range(bsz):
+                curr_required = blocks_required[i]
+                block_tables[i, :curr_required] = torch.arange(
+                    start_idx, start_idx + curr_required, device=block_tables.device
+                )
+                start_idx += curr_required
+        else:
+            # non-contiguous cache
+            available_block_ids = torch.nonzero(self._block_states > 0).view(-1)
+            alloc_block_ids = available_block_ids[:num_blocks_required]
+            alloc_block_ids = alloc_block_ids.to(dtype=block_tables.dtype, device=block_tables.device)
+            start_idx = 0
+            for i in range(bsz):
+                curr_required = blocks_required[i]
+                block_tables[i, :curr_required] = alloc_block_ids[start_idx, start_idx + curr_required]
+                start_idx += curr_required
+
+        # Update cache blocks
+        self._block_states[alloc_block_ids] = 0
+        self._available_blocks -= num_blocks_required
+        last_block_locs = torch.cumsum(blocks_required, dim=0) - 1
+        last_block_locs = last_block_locs.to(device=alloc_block_ids.device)
+
+        for i, block_id in enumerate(alloc_block_ids[last_block_locs]):
+            block: CacheBlock = self._cache_blocks[block_id]
+            block.add_ref()
+            self._allocate_on_block(
+                block,
+                block.block_size
+                if context_lengths[i] % block.block_size == 0
+                else context_lengths[i].item() % block.block_size,
+            )
+        for block_id in alloc_block_ids:
+            if block_id in alloc_block_ids[last_block_locs]:
+                continue
+            block: CacheBlock = self._cache_blocks[block_id]
+            block.add_ref()
+            self._allocate_on_block(block, block.block_size)
+
     def allocate_token_from_block_table(self, block_table: torch.Tensor, context_len: int) -> None:
         """Allocate the logical cache block for a single sequence during decoding stage,
         and updates the provided block table if a new cache block is needed.
 
         Args:
-            block_table: A 1D tensor of shape [max_blocks_per_sequence] holded by a sequence, storing mapping of token_position_id -> block_id.
+            block_table: A 1D tensor of shape [max_blocks_per_sequence], mapping of token_position_id -> block_id.
             context_len: The length of the processing sequnece (already-allocated length).
         """
         assert block_table.dim() == 1
@@ -207,12 +282,79 @@ class KVCacheManager:
         alloc_local_block_idx = context_len // self.block_size
         return self.allocate_single_block(block_table, alloc_local_block_idx)
 
+    def allocate_tokens_from_block_tables(
+        self, block_tables: torch.Tensor, context_lens: torch.Tensor, bsz: int = None
+    ) -> List[int]:
+        """Allocate logical cache blocks for a batch of sequences during decoding stage.
+
+        Usage:
+            allocate_context_from_block_tables
+            model forward (block tables & context lengths passed)
+            update context lengths
+            allocate_tokens_from_block_tables
+            model forward
+            update context lengths
+            allocate_tokens_from_block_tables
+            model forward
+            update context lengths
+            ...
+
+        Args:
+            block_tables (torch.Tensor): [bsz, max_blocks_per_sequence]
+            context_lengths (torch.Tensor): [bsz]
+
+        Returns:
+            List[int]: list of sequence uid to be recycled
+        """
+        assert block_tables.dim() == 2
+        assert context_lens.dim() == 1
+
+        bsz = block_tables.size(0) if bsz is None else bsz
+
+        alloc_local_block_indexes = (context_lens[:bsz]) // self.block_size
+        block_global_ids = block_tables[torch.arange(0, bsz), alloc_local_block_indexes]
+        seqs_to_recycle = []
+        new_blocks_required = torch.sum(block_global_ids < 0).item()
+        seqs_req_new_blocks = torch.nonzero(block_global_ids < 0).squeeze()
+
+        if new_blocks_required > 0:
+            if new_blocks_required > self._available_blocks:
+                # TODO might want to revise the logic here
+                # Process the first (_available_blocks) sequences that require new blocks
+                # Put the rest of the sequences back to recycled
+                seqs_req_new_blocks, seqs_to_recycle = (
+                    seqs_req_new_blocks[: self._available_blocks],
+                    seqs_req_new_blocks[self._available_blocks :],
+                )
+                for seq_id in seqs_to_recycle:
+                    self.free_block_table(block_tables[seq_id])
+                new_blocks_required = self._available_blocks
+
+            # NOTE might want to alloc contiguous logic
+            free_block_ids = torch.nonzero(self._block_states > 0).view(-1)
+            alloc_block_ids = free_block_ids[:new_blocks_required].to(
+                dtype=block_tables.dtype, device=block_tables.device
+            )
+
+            for block_id in alloc_block_ids:
+                block: CacheBlock = self._cache_blocks[block_id]
+                block.add_ref()
+                self._block_states[block_id] = 0
+                self._available_blocks -= 1
+            block_tables[seqs_req_new_blocks, alloc_local_block_indexes[seqs_req_new_blocks]] = alloc_block_ids
+            block_global_ids = block_tables[torch.arange(0, bsz), alloc_local_block_indexes]
+
+        for block_id in block_global_ids:
+            self._allocate_on_block(self._cache_blocks[block_id], 1)
+
+        return seqs_to_recycle
+
     def allocate_single_block(self, block_table: torch.Tensor, block_local_idx: int) -> int:
         """Allocate space asked on a single block in the block table, specified by the provided position id,
         and updates the provided block table with the allocated block.
 
         Args:
-            block_table: A 1D tensor of shape [max_blocks_per_sequence] holded by a sequence, storing mapping of token_position_id -> block_id.
+            block_table: A 1D tensor of shape [max_blocks_per_sequence], mapping of token_position_id -> block_id.
             block_local_idx: The index of the block in the block table.
             space_asked: i.e. The number of tokens to be assigned space for.
         Returns:
@@ -240,8 +382,7 @@ class KVCacheManager:
     def free_block_table(self, block_table: torch.Tensor) -> None:
         """Free the logical cache blocks for **a single sequence**."""
         assert block_table.dim() == 1
-        for i in range(block_table.numel()):
-            global_block_id = block_table[i].item()
+        for i, global_block_id in enumerate(block_table.tolist()):
             if global_block_id < 0:
                 return
             block: CacheBlock = self._cache_blocks[global_block_id]
@@ -253,6 +394,15 @@ class KVCacheManager:
                 # reset the block id in the block table (if we maintain a 2D tensors as block tables in Engine)
                 block_table[i] = -1
 
+    def free_block_tables(self, block_tables: torch.Tensor, first_n: int = None) -> None:
+        """Release the logical cache blocks for a batch of sequences.
+        If `first_n` is provided, only the blocks for the first several sequences will be released.
+        """
+        assert block_tables.dim() == 2
+        first_n = block_tables.size(0) if first_n is None else first_n
+        for block_table in block_tables[:first_n]:
+            self.free_block_table(block_table)
+
     def clear_all(self) -> None:
         """Clear all the references and allocations on all the cache blocks."""
         for block in self._cache_blocks:
diff --git a/colossalai/inference/modeling/models/nopadding_llama.py b/colossalai/inference/modeling/models/nopadding_llama.py
index a1db4ecfa..6b6a5876b 100644
--- a/colossalai/inference/modeling/models/nopadding_llama.py
+++ b/colossalai/inference/modeling/models/nopadding_llama.py
@@ -12,8 +12,8 @@ from transformers.models.llama.modeling_llama import (
     LlamaModel,
 )
 
+from colossalai.inference.batch_bucket import BatchBucket
 from colossalai.inference.flash_decoding_utils import FDIntermTensors
-from colossalai.inference.struct import BatchInfo
 from colossalai.kernel.triton import (
     context_attention_unpadded,
     copy_kv_to_blocked_cache,
@@ -34,7 +34,7 @@ except ImportError:
 
 def llama_causal_lm_forward(
     self: LlamaForCausalLM,
-    batch: BatchInfo = None,
+    batch: BatchBucket = None,
     k_caches: List[torch.Tensor] = None,
     v_caches: List[torch.Tensor] = None,
 ):
@@ -59,7 +59,7 @@ def llama_causal_lm_forward(
 
 def llama_model_forward(
     self: LlamaModel,
-    batch: BatchInfo = None,
+    batch: BatchBucket = None,
     k_caches: List[torch.Tensor] = None,
     v_caches: List[torch.Tensor] = None,
 ):
@@ -73,7 +73,7 @@ def llama_model_forward(
     input_ids = batch.get_1D_inputs()
     block_tables = batch.get_block_table_tensor()
     sequence_lengths = batch.get_sequence_lengths()
-    batch_size = len(sequence_lengths)
+    batch_size = batch.current_batch_size
     kv_seq_len = sequence_lengths.max().item()
 
     hidden_states = self.embed_tokens(input_ids)
diff --git a/colossalai/inference/struct.py b/colossalai/inference/struct.py
index 766e54ab1..706304038 100644
--- a/colossalai/inference/struct.py
+++ b/colossalai/inference/struct.py
@@ -71,7 +71,6 @@ class Sequence:
     input_token_id: List[int]
     block_size: int
     sample_params: Any  # SampleParams needs to be imported later.
-    block_table: torch.Tensor
     eos_token_id: int
     pad_token_id: int
     max_output_len: int = 256
@@ -158,7 +157,6 @@ class Sequence:
             f"prompt={self.prompt}, "
             f"status={self.status.name}, "
             f"sample_params={self.sample_params}, "
-            f"logical_block_number={self.block_table.shape[0]},"
             f"input_len={self.input_len}),"
             f"output_len={self.output_len})"
         )
diff --git a/tests/test_infer/test_batch_bucket.py b/tests/test_infer/test_batch_bucket.py
new file mode 100644
index 000000000..e2d5774f4
--- /dev/null
+++ b/tests/test_infer/test_batch_bucket.py
@@ -0,0 +1,140 @@
+import torch
+from transformers.models.llama import LlamaConfig
+
+from colossalai.inference.batch_bucket import BatchBucket
+from colossalai.inference.config import InferenceConfig
+from colossalai.inference.kv_cache import KVCacheManager
+from colossalai.inference.struct import Sequence
+from colossalai.testing import parameterize
+
+
+@parameterize(
+    "test_config",
+    [
+        {
+            "hidden_size": 128,
+            "num_attention_heads": 4,
+            "num_layers": 2,
+            "block_size": 4,
+            "max_batch_size": 4,
+            "max_input_len": 32,
+            "max_output_len": 8,
+            "dtype": torch.float16,
+            "tp_size": 1,
+        }
+    ],
+)
+def test_bucket(test_config):
+    hidden_size = test_config.pop("hidden_size")
+    num_heads = test_config.pop("num_attention_heads")
+    num_layers = test_config.pop("num_layers")
+    model_config = LlamaConfig(
+        hidden_size=hidden_size,
+        num_hidden_layers=num_layers,
+        num_attention_heads=num_heads,
+    )
+    inference_config = InferenceConfig(**test_config)
+
+    # Just for testing usage. Don't create multiple cache_manager on the same device.
+    cache_manager = KVCacheManager(inference_config, model_config)
+    cache_manager_copy = KVCacheManager(inference_config, model_config)
+
+    seq_lens = [19, 20, 27]
+    seq1 = Sequence(
+        request_id=0,
+        prompt="",  # Dummy for testing usage
+        input_token_id=list(range(seq_lens[0])),
+        block_size=4,
+        sample_params=None,
+        eos_token_id=2,
+        pad_token_id=2,
+        max_output_len=10,
+    )
+    seq2 = Sequence(
+        request_id=1,
+        prompt="",  # Dummy for testing usage
+        input_token_id=list(range(seq_lens[1])),
+        block_size=4,
+        sample_params=None,
+        eos_token_id=2,
+        pad_token_id=2,
+        max_output_len=10,
+    )
+    seq3 = Sequence(
+        request_id=2,
+        prompt="",  # Dummy for testing usage
+        input_token_id=list(range(seq_lens[2])),
+        block_size=4,
+        sample_params=None,
+        eos_token_id=2,
+        pad_token_id=2,
+        max_output_len=10,
+    )
+
+    block_size = test_config["block_size"]
+    max_batch_size = test_config["max_batch_size"]
+    max_length = test_config["max_input_len"] + test_config["max_output_len"]
+    assert max_batch_size >= 2, "max_batch_size should be greater than 1"
+
+    bb = BatchBucket(
+        num_heads, cache_manager.get_head_size(), max_batch_size, max_length, block_size, kv_max_split_num=2
+    )
+    bb_copy = BatchBucket(
+        num_heads, cache_manager.get_head_size(), max_batch_size, max_length, block_size, kv_max_split_num=2
+    )
+    block_tables = bb.add_seqs([seq1, seq2])
+    assert block_tables.shape == (2, cache_manager.max_blocks_per_sequence)
+    assert torch.all(block_tables < 0), "Initialized block_tables should be negative values"
+
+    cache_manager.allocate_context_from_block_tables(block_tables, bb.seq_lengths[: bb.current_batch_size])
+    bb_copy.add_seqs(
+        [seq1, seq2], alloc_block_tables_fn=cache_manager_copy.allocate_context_from_block_tables
+    )  # This is just for testing usage. Don't add the same sequence to different buckets.
+
+    assert bb.seq_lengths.tolist() == [seq1.sentence_len, seq2.sentence_len] + [0] * (
+        max_batch_size - bb.current_batch_size
+    )
+    assert torch.equal(bb.block_tables, bb_copy.block_tables)
+
+    bb.append_batch_tokens(torch.tensor([99, 99]))
+    assert bb.seq_lengths.tolist() == [seq1.sentence_len, seq2.sentence_len] + [0] * (
+        max_batch_size - bb.current_batch_size
+    )
+
+    cache_manager.allocate_tokens_from_block_tables(bb.block_tables, bb.seq_lengths, bsz=bb.current_batch_size)
+    assert bb.seq_lengths.tolist() == [seq1.sentence_len, seq2.sentence_len] + [0] * (
+        max_batch_size - bb.current_batch_size
+    )
+
+    bb.append_batch_tokens(torch.tensor([99, 99]))
+
+    cache_manager.allocate_tokens_from_block_tables(bb.block_tables, bb.seq_lengths, bsz=bb.current_batch_size)
+    assert bb.seq_lengths.tolist() == [seq1.sentence_len, seq2.sentence_len] + [0] * (
+        max_batch_size - bb.current_batch_size
+    )
+
+    bb.pop_seq_update_batch(0, free_block_table_fn=cache_manager.free_block_table)
+    assert bb.seq_lengths.tolist() == [bb.seqs_li[0].sentence_len] + [0] * (max_batch_size - bb.current_batch_size)
+    assert bb.is_compact
+
+    bb2 = BatchBucket(
+        num_heads, cache_manager.get_head_size(), max_batch_size, max_length, block_size, kv_max_split_num=2
+    )
+    block_tables = bb2.add_seqs([seq3])
+    cache_manager.allocate_context_from_block_tables(block_tables, bb2.seq_lengths[: bb2.current_batch_size])
+    unmerged_ids = bb.merge(bb2)
+    assert not unmerged_ids
+    assert bb.is_compact
+    assert bb2.is_compact
+    assert bb.current_batch_size == 2
+    assert bb2.current_batch_size == 0
+
+    bb.clear(cache_manager.free_block_tables)
+    assert bb.current_batch_size == 0
+    assert bb.is_compact
+    assert bb.seq_lengths.tolist() == [0] * max_batch_size
+    assert torch.all(bb.block_tables < 0)
+
+
+if __name__ == "__main__":
+    test_bucket()
diff --git a/tests/test_infer/test_config_and_struct.py b/tests/test_infer/test_config_and_struct.py
index 47d3839e4..046ee932d 100755
--- a/tests/test_infer/test_config_and_struct.py
+++ b/tests/test_infer/test_config_and_struct.py
@@ -15,7 +15,6 @@ def check_config_and_inference():
         input_token_id=[1, 2, 3],
         block_size=16,
         sample_params=None,
-        block_table=None,
         eos_token_id=2,
         pad_token_id=2,
         max_output_len=256,
@@ -27,7 +26,6 @@ def check_config_and_inference():
         input_token_id=[4, 5, 6],
         block_size=16,
         sample_params=None,
-        block_table=None,
         eos_token_id=2,
         pad_token_id=2,
         max_output_len=256,
@@ -39,7 +37,6 @@ def check_config_and_inference():
         input_token_id=[7, 8, 9],
         block_size=16,
         sample_params=None,
-        block_table=None,
         eos_token_id=2,
         pad_token_id=2,
         max_output_len=256,
diff --git a/tests/test_infer/test_kvcache_manager.py b/tests/test_infer/test_kvcache_manager.py
index a2051f220..321047706 100755
--- a/tests/test_infer/test_kvcache_manager.py
+++ b/tests/test_infer/test_kvcache_manager.py
@@ -148,6 +148,20 @@ def check_cache_manager(test_config):
     cache_manager.clear_all()
     assert cache_manager.num_available_blocks == num_blocks
 
+    for cache_block in cache_manager._cache_blocks:
+        assert cache_block.available_space == block_size
+
+    # Mock batch operations (Prefill/Decoding updates)
+    context_lengths = torch.tensor([max_input_length, max_input_length - 1])
+    block_tables = torch.tensor(
+        [[-1 for _ in range(cache_manager.max_blocks_per_sequence)] for _ in range(2)], dtype=torch.int32
+    )
+    cache_manager.allocate_context_from_block_tables(block_tables, context_lengths)
+    cache_manager.allocate_tokens_from_block_tables(block_tables, context_lengths)
+    cache_manager.free_block_tables(block_tables)
+    for cache_block in cache_manager._cache_blocks:
+        assert cache_block.available_space == block_size
+
 
 def run_dist(rank, world_size, port):
     colossalai.launch(config={}, rank=rank, world_size=world_size, port=port, host="localhost")
diff --git a/tests/test_infer/test_request_handler.py b/tests/test_infer/test_request_handler.py
index d589e9717..c7a35ebbe 100644
--- a/tests/test_infer/test_request_handler.py
+++ b/tests/test_infer/test_request_handler.py
@@ -1,5 +1,4 @@
 import pytest
-import torch
 from transformers.models.llama import LlamaConfig
 
 import colossalai
@@ -22,17 +21,35 @@ def check_running_list():
         eos_token_id=0,
         pad_token_id=0,
         sample_params=None,
-        block_table=1,
     )
-
+    seq2 = Sequence(
+        request_id=2,
+        prompt="abc",
+        input_token_id=[1, 2, 3],
+        block_size=16,
+        eos_token_id=0,
+        pad_token_id=0,
+        sample_params=None,
+    )
     running_list.append(seq1)
+    running_list.append(seq2)
     assert running_list.ready_for_prefill()
-    assert running_list.decoding == [] and running_list.prefill[0] == seq1
+    assert len(running_list.decoding) == 0
+    assert len(running_list.prefill) > 0 and running_list.prefill[0] == seq1
 
     seq = running_list.find_seq(seq1.request_id)
     assert seq == seq1
 
+    running_list.mark_prefill_running()
+    for seq in running_list.prefill:
+        assert seq.status == RequestStatus.RUNNING
+
+    running_list.move_prefill_to_decoding([seq1.request_id, seq2.request_id])
+    assert len(running_list.prefill) == 0
+    assert len(running_list.decoding) > 0 and running_list.decoding[0] == seq1
+
     running_list.remove(seq1)
+    running_list.remove(seq2)
     assert running_list.is_empty()
 
 
@@ -59,7 +76,6 @@ def check_request_handler():
         eos_token_id=0,
         pad_token_id=0,
         sample_params=None,
-        block_table=torch.tensor([-1, -1]),
     )
     request_handler.add_sequence(seq1)
     # the priority should be 1