dynamo/lib/bindings/python/tests/test_mm_kv_router.py

437 lines
14 KiB
Python

# SPDX-FileCopyrightText: Copyright (c) 2025-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
# SPDX-License-Identifier: Apache-2.0
"""
Tests for Multimodal KV Router functionality.
These tests verify that the KV router correctly handles multimodal content (images, videos)
by distinguishing between requests with identical token sequences but different MM objects.
Key Concepts:
- block_hash: External hash used to identify blocks uniquely (includes MM info)
- tokens_hash: Local hash based only on token content
- mm_hash: Hash of the multimodal object (image, video, etc.)
Test Strategy:
- Use RadixTree directly to avoid NATS/etcd infrastructure dependencies
- Simulate multiple workers caching same tokens with different MM content
- Verify that routing distinguishes between different MM objects
"""
import json
from typing import Any
import pytest
from dynamo.llm import RadixTree, compute_block_hash_for_seq
pytestmark = pytest.mark.pre_merge
# Constants for testing
DEFAULT_BLOCK_SIZE = 32
MM_HASH_1 = 0xDEADBEEF
MM_HASH_2 = 0xCAFEBABE
MM_HASH_3 = 0xFEEDFACE
def make_mm_info(mm_hash: int, offsets: list[list[int]] | None = None) -> dict:
"""Create a block's MM extra info structure."""
if offsets is None:
offsets = [[0, 10]]
return {"mm_objects": [{"mm_hash": mm_hash, "offsets": offsets}]}
def make_store_event(
event_id: int,
blocks: list[dict],
parent_hash: int | None = None,
) -> bytes:
"""Create a JSON-encoded store event for RadixTree."""
event = {
"event_id": event_id,
"data": {
"stored": {
"parent_hash": parent_hash,
"blocks": blocks,
}
},
}
return json.dumps(event).encode("utf-8")
def make_block(
block_hash: int,
tokens_hash: int | None = None,
mm_info: dict | None = None,
) -> dict:
"""Create a block structure for store events."""
block: dict[str, Any] = {
"block_hash": block_hash,
"tokens_hash": tokens_hash if tokens_hash is not None else block_hash,
}
if mm_info is not None:
block["mm_extra_info"] = mm_info
return block
# =============================================================================
# RadixTree MM Routing Tests
# =============================================================================
# # @pytest.mark.timeout(5)
def test_radix_tree_mm_routing_basic():
"""Test RadixTree correctly distinguishes blocks with same tokens but different MM content."""
radix_tree = RadixTree()
# Worker 0: Store block with MM Object 1
worker_0, block_hash_w0 = 0, 1000
event_w0 = make_store_event(
event_id=1,
blocks=[make_block(block_hash_w0, mm_info=make_mm_info(MM_HASH_1))],
)
radix_tree.apply_event(worker_0, event_w0)
# Worker 1: Store block with DIFFERENT MM Object (same tokens)
worker_1, block_hash_w1 = 1, 2000
event_w1 = make_store_event(
event_id=2,
blocks=[make_block(block_hash_w1, mm_info=make_mm_info(MM_HASH_2))],
)
radix_tree.apply_event(worker_1, event_w1)
# Verify both blocks are stored
all_blocks = radix_tree.dump_tree_as_events()
assert len(all_blocks) == 2
# Query for worker 0's block
scores_w0 = radix_tree.find_matches([block_hash_w0])
assert (worker_0, 0) in scores_w0.scores
assert scores_w0.scores[(worker_0, 0)] == 1
# Query for worker 1's block
scores_w1 = radix_tree.find_matches([block_hash_w1])
assert (worker_1, 0) in scores_w1.scores
assert scores_w1.scores[(worker_1, 0)] == 1
# Query with non-existent hash should return no matches
scores_none = radix_tree.find_matches([9999])
assert len(scores_none.scores) == 0
# @pytest.mark.timeout(5)
def test_radix_tree_mm_block_chaining():
"""Test block chaining with parent_hash for multi-block sequences with MM content."""
radix_tree = RadixTree()
worker_id = 0
parent_hash = 1000
child_hash = 2000
# Store parent block
parent_event = make_store_event(
event_id=1,
blocks=[make_block(parent_hash, mm_info=make_mm_info(MM_HASH_1))],
)
radix_tree.apply_event(worker_id, parent_event)
# Store child block that references parent
child_event = make_store_event(
event_id=2,
blocks=[make_block(child_hash, mm_info=make_mm_info(MM_HASH_1))],
parent_hash=parent_hash,
)
radix_tree.apply_event(worker_id, child_event)
# Verify chain exists
all_blocks = radix_tree.dump_tree_as_events()
assert len(all_blocks) == 2
# Query with both hashes should match the chain
scores = radix_tree.find_matches([parent_hash, child_hash])
assert (worker_id, 0) in scores.scores
assert scores.scores[(worker_id, 0)] == 2
# @pytest.mark.timeout(5)
def test_radix_tree_worker_removal():
"""Test worker removal clears all its blocks."""
radix_tree = RadixTree()
worker_0, worker_1 = 0, 1
# Add blocks for both workers
radix_tree.apply_event(
worker_0,
make_store_event(1, [make_block(1000, mm_info=make_mm_info(MM_HASH_1))]),
)
radix_tree.apply_event(
worker_1,
make_store_event(2, [make_block(2000, mm_info=make_mm_info(MM_HASH_2))]),
)
assert len(radix_tree.dump_tree_as_events()) == 2
# Remove worker 0
radix_tree.remove_worker(worker_0)
# Only worker 1's block should remain
remaining = radix_tree.dump_tree_as_events()
assert len(remaining) == 1
scores = radix_tree.find_matches([2000])
assert (worker_1, 0) in scores.scores
# @pytest.mark.timeout(5)
def test_radix_tree_clear_all_blocks():
"""Test clearing all blocks for a specific worker."""
radix_tree = RadixTree()
worker_id = 0
# Add multiple blocks
radix_tree.apply_event(
worker_id,
make_store_event(1, [make_block(1000), make_block(2000)]),
)
assert len(radix_tree.dump_tree_as_events()) == 2
# Clear all blocks for worker
radix_tree.clear_all_blocks(worker_id)
assert len(radix_tree.dump_tree_as_events()) == 0
# =============================================================================
# Block Hash Computation Tests
# =============================================================================
# @pytest.mark.timeout(5)
def test_mm_block_hash_computation_basic():
"""Test that same tokens with different MM content produce different hashes."""
tokens = [100] * DEFAULT_BLOCK_SIZE
# Without MM info
hashes_no_mm = compute_block_hash_for_seq(tokens, DEFAULT_BLOCK_SIZE)
assert len(hashes_no_mm) == 1
# With MM info 1
hashes_mm1 = compute_block_hash_for_seq(
tokens, DEFAULT_BLOCK_SIZE, [make_mm_info(MM_HASH_1)]
)
assert len(hashes_mm1) == 1
# With MM info 2
hashes_mm2 = compute_block_hash_for_seq(
tokens, DEFAULT_BLOCK_SIZE, [make_mm_info(MM_HASH_2)]
)
assert len(hashes_mm2) == 1
# All three should be different
assert hashes_no_mm != hashes_mm1
assert hashes_no_mm != hashes_mm2
assert hashes_mm1 != hashes_mm2
# @pytest.mark.timeout(5)
def test_mm_block_hash_determinism():
"""Test that hash computation is deterministic."""
tokens = [100] * DEFAULT_BLOCK_SIZE
mm_info = [make_mm_info(MM_HASH_1)]
hash1 = compute_block_hash_for_seq(tokens, DEFAULT_BLOCK_SIZE, mm_info)
hash2 = compute_block_hash_for_seq(tokens, DEFAULT_BLOCK_SIZE, mm_info)
assert hash1 == hash2
# @pytest.mark.timeout(5)
@pytest.mark.parametrize("block_size", [16, 32, 64])
def test_mm_block_hash_multiple_blocks(block_size: int):
"""Test hash computation for sequences spanning multiple blocks."""
num_blocks = 3
# Use different tokens per block to get unique hashes
tokens = []
for i in range(num_blocks):
tokens.extend([100 + i] * block_size)
# One MM info per block
mm_infos = [make_mm_info(MM_HASH_1) for _ in range(num_blocks)]
hashes = compute_block_hash_for_seq(tokens, block_size, mm_infos)
assert len(hashes) == num_blocks
# Each block should have a unique hash (due to different tokens)
assert len(set(hashes)) == num_blocks
# @pytest.mark.timeout(5)
def test_mm_block_hash_partial_block():
"""Test hash computation when tokens don't fill complete blocks."""
# 1.5 blocks worth of tokens
tokens = [100] * (DEFAULT_BLOCK_SIZE + DEFAULT_BLOCK_SIZE // 2)
# MM info for each block
mm_infos = [make_mm_info(MM_HASH_1), make_mm_info(MM_HASH_2)]
hashes = compute_block_hash_for_seq(tokens, DEFAULT_BLOCK_SIZE, mm_infos)
# Only complete blocks get hashes - partial blocks are not hashed
assert len(hashes) == 1
# @pytest.mark.timeout(5)
def test_mm_block_hash_none_mm_info():
"""Test that None MM info is handled correctly."""
tokens = [100] * DEFAULT_BLOCK_SIZE
# Pass None for some blocks' MM info
mm_infos = [None]
hashes_with_none = compute_block_hash_for_seq(tokens, DEFAULT_BLOCK_SIZE, mm_infos)
hashes_without = compute_block_hash_for_seq(tokens, DEFAULT_BLOCK_SIZE)
# Both should produce the same result
assert hashes_with_none == hashes_without
# @pytest.mark.timeout(5)
def test_mm_block_hash_different_offsets():
"""Test that same mm_hash with different offsets produces same hash."""
tokens = [100] * DEFAULT_BLOCK_SIZE
# Same MM hash, different offsets
mm_info_1 = make_mm_info(MM_HASH_1, offsets=[[0, 10]])
mm_info_2 = make_mm_info(MM_HASH_1, offsets=[[5, 15]])
hash1 = compute_block_hash_for_seq(tokens, DEFAULT_BLOCK_SIZE, [mm_info_1])
hash2 = compute_block_hash_for_seq(tokens, DEFAULT_BLOCK_SIZE, [mm_info_2])
# Currently offsets are not included in hash computation - just mm_hash
# This behavior may change - update test if needed
assert hash1 == hash2
# @pytest.mark.timeout(5)
def test_mm_block_hash_multiple_mm_objects():
"""Test hash with multiple MM objects in a single block."""
tokens = [100] * DEFAULT_BLOCK_SIZE
# Multiple MM objects in one block
mm_info = {
"mm_objects": [
{"mm_hash": MM_HASH_1, "offsets": [[0, 5]]},
{"mm_hash": MM_HASH_2, "offsets": [[10, 15]]},
]
}
hashes = compute_block_hash_for_seq(tokens, DEFAULT_BLOCK_SIZE, [mm_info])
assert len(hashes) == 1
# Compare with single MM object
single_mm_hashes = compute_block_hash_for_seq(
tokens, DEFAULT_BLOCK_SIZE, [make_mm_info(MM_HASH_1)]
)
# Should be different due to additional MM object
assert hashes != single_mm_hashes
# @pytest.mark.timeout(5)
def test_mm_block_hash_error_zero_block_size():
"""Test that zero block size raises an error."""
tokens = [100] * 32
with pytest.raises(ValueError, match="kv_block_size cannot be 0"):
compute_block_hash_for_seq(tokens, 0)
# =============================================================================
# Integration Tests: RadixTree + Hash Computation
# =============================================================================
# @pytest.mark.timeout(5)
def test_integration_mm_hash_to_routing():
"""Test end-to-end: compute hash -> store in tree -> query matches correctly."""
radix_tree = RadixTree()
tokens = [100] * DEFAULT_BLOCK_SIZE
# Compute hashes for two different MM contents
hash_mm1 = compute_block_hash_for_seq(
tokens, DEFAULT_BLOCK_SIZE, [make_mm_info(MM_HASH_1)]
)[0]
hash_mm2 = compute_block_hash_for_seq(
tokens, DEFAULT_BLOCK_SIZE, [make_mm_info(MM_HASH_2)]
)[0]
# Store each on different workers
worker_0, worker_1 = 0, 1
radix_tree.apply_event(
worker_0,
make_store_event(1, [make_block(hash_mm1, mm_info=make_mm_info(MM_HASH_1))]),
)
radix_tree.apply_event(
worker_1,
make_store_event(2, [make_block(hash_mm2, mm_info=make_mm_info(MM_HASH_2))]),
)
# Query with MM1's hash should match worker 0
scores_mm1 = radix_tree.find_matches([hash_mm1])
assert (worker_0, 0) in scores_mm1.scores
assert (worker_1, 0) not in scores_mm1.scores
# Query with MM2's hash should match worker 1
scores_mm2 = radix_tree.find_matches([hash_mm2])
assert (worker_1, 0) in scores_mm2.scores
assert (worker_0, 0) not in scores_mm2.scores
# @pytest.mark.timeout(5)
@pytest.mark.parametrize("num_workers", [2, 3, 5])
def test_integration_multiple_workers_same_tokens(num_workers: int):
"""Test routing with multiple workers caching same tokens but different MM content."""
radix_tree = RadixTree()
tokens = [100] * DEFAULT_BLOCK_SIZE
# Each worker has unique MM content
mm_hashes = [0x1000 + i for i in range(num_workers)]
# Store blocks for each worker
for worker_id, mm_hash in enumerate(mm_hashes):
block_hash = compute_block_hash_for_seq(
tokens, DEFAULT_BLOCK_SIZE, [make_mm_info(mm_hash)]
)[0]
radix_tree.apply_event(
worker_id,
make_store_event(
event_id=worker_id + 1,
blocks=[make_block(block_hash, mm_info=make_mm_info(mm_hash))],
),
)
# Verify all blocks stored
assert len(radix_tree.dump_tree_as_events()) == num_workers
# Query for each worker's block should match only that worker
for worker_id, mm_hash in enumerate(mm_hashes):
block_hash = compute_block_hash_for_seq(
tokens, DEFAULT_BLOCK_SIZE, [make_mm_info(mm_hash)]
)[0]
scores = radix_tree.find_matches([block_hash])
assert (worker_id, 0) in scores.scores
assert scores.scores[(worker_id, 0)] == 1
# No other workers should match
for other_id in range(num_workers):
if other_id != worker_id:
assert (other_id, 0) not in scores.scores