init

tests/prefix_caching/test_prefix_caching.py

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+"""Compare the with and without prefix caching.
+
+Run `pytest tests/prefix_caching/test_prefix_caching.py`.
+"""
+import pytest
+
+from vllm.core.block_manager_v1 import CachedBlockAllocator
+from vllm.utils import Device
+
+
+@pytest.mark.parametrize("block_size", [16])
+@pytest.mark.parametrize("num_blocks", [16])
+def test_block_allocator(
+    block_size: int,
+    num_blocks: int,
+):
+    block_hash = 1
+    block_allocator = CachedBlockAllocator(Device.CPU, block_size, num_blocks)
+
+    # Allocate two PysicalTokenBlocks with the same hash and check
+    # that they are the same PhysicalTokenBlock
+    first_block = block_allocator.allocate(block_hash, 0)
+    second_block = block_allocator.allocate(block_hash, 0)
+    assert (first_block == second_block)
+    assert (second_block.ref_count == 2)
+
+    # Free the first_block and confirm that the ref_count is correctly
+    # decremented on the second block
+    block_allocator.free(first_block)
+    assert (second_block.ref_count == 1)
+
+    # Free the second block
+    block_allocator.free(second_block)
+
+    # Reallocate the first block and confirm that, even after the block
+    # had its ref_count go to 0, we still get the same block back
+    first_block = block_allocator.allocate(block_hash, 0)
+    assert (first_block == second_block)
+    assert (first_block.block_hash == block_hash)
+
+
+@pytest.mark.parametrize("num_blocks", [16])
+def test_eviction(num_blocks: int, ):
+    block_size = 16
+    block_allocator = CachedBlockAllocator(Device.CPU, block_size, num_blocks)
+    blocks = []
+
+    for i in range(num_blocks):
+        # use i as the block_hash
+        blocks.append(block_allocator.allocate(i, 0))
+
+    #Free all blocks
+    for block in blocks:
+        block_allocator.free(block)
+
+    # Allocate a new block and confirm that it's the first block freed.
+    # I.E The Least Recently Used block
+    new_block_hash = block_size
+    new_block = block_allocator.allocate(new_block_hash, 0)
+    assert (new_block == blocks[0])
+    assert (new_block.block_hash == new_block_hash)
+
+    # Reallocate the second in blocks to remove it from the free list
+    realloc_block_hash = 1
+    realloc_block = block_allocator.allocate(realloc_block_hash, 0)
+    assert (realloc_block == blocks[realloc_block_hash])
+    assert (realloc_block.block_hash == realloc_block_hash)
+
+    # Allocate a new block and confirm that it's not the realloc_block,
+    # since the realloc_block shouldn't be in the free list
+    new_block_hash = block_size + 1
+    new_block = block_allocator.allocate(new_block_hash, 0)
+    assert (realloc_block != new_block)
+    assert (new_block.block_hash == new_block_hash)
+    assert (new_block.block_number == 2)