[6/6][kimi-deterministic] Use deterministic seeded coins for EAGLE rejection sampling (#30822)

This commit is contained in:
Yuzhen Zhou
2026-07-24 02:11:21 -07:00
committed by GitHub
parent 3849beb7e3
commit b954e9cf3d
19 changed files with 562 additions and 23 deletions
@@ -11,7 +11,11 @@ import torch
import torch.nn.functional as F
from einops import rearrange, repeat
from sglang.kernels.ops.attention.flash_attention import flash_attn_varlen_func
from sglang.kernels.ops.attention.flash_attention import (
flash_attn_varlen_func,
flash_attn_with_kvcache,
)
from sglang.srt.utils import is_sm100_or_sm110_supported
from sglang.test.ci.ci_register import register_cuda_ci
register_cuda_ci(est_time=120, stage="base-b-kernel-unit", runner_config="1-gpu-large")
@@ -1507,5 +1511,112 @@ def _generate_block_kvcache(
return k_cache, v_cache, page_table, k_cache_paged, v_cache_paged, num_blocks
@pytest.mark.skipif(
not is_sm100_or_sm110_supported(),
reason="flash_attn.cute implements qv on SM100/SM110 only (not SM120).",
)
@pytest.mark.parametrize("mha_type", ["mqa", "gqa"])
@pytest.mark.parametrize(
"seqlen_q,seqlen_k",
[
(1, 128), # plain decode
(4, 1024), # speculative decode (multiple q rows per request)
(64, 800), # chunked extend
(16, 20000), # long context
],
)
def test_flash_attn_varlen_qv_deepseek_absorbed(seqlen_q, seqlen_k, mha_type):
"""DeepSeek absorbed-MLA FA4 shape: rope q/k head_dim 64, latent v/qv
head_dim 512, varlen q over a paged KV cache, num_splits=1. Mirrors the
production calls in flashattention_backend.py, where extend
(flash_attn_varlen_func) and decode (flash_attn_with_kvcache) share this
qv-threaded path.
"""
device = "cuda"
dtype = torch.bfloat16
torch.random.manual_seed(seqlen_q + seqlen_k)
batch_size = 5
nheads = 8
nheads_k = 1 if mha_type == "mqa" else 4
d, dv = 64, 512
page_size = 128
q = torch.randn(batch_size, seqlen_q, nheads, d, device=device, dtype=dtype)
qv = torch.randn(batch_size, seqlen_q, nheads, dv, device=device, dtype=dtype)
k_cache, v_cache, page_table, k_cache_paged, v_cache_paged, _ = (
_generate_block_kvcache(
seqlen_k, page_size, batch_size, nheads_k, d, dv, device, dtype, dtype
)
)
cache_seqlens = torch.randint(
seqlen_q, seqlen_k + 1, (batch_size,), dtype=torch.int32, device=device
)
cache_seqlens[0] = seqlen_k
cu_seqlens_q = (
torch.arange(batch_size + 1, dtype=torch.int32, device=device) * seqlen_q
)
out_unpad = flash_attn_varlen_func(
rearrange(q, "b s h d -> (b s) h d"),
k_cache_paged,
v_cache_paged,
qv=rearrange(qv, "b s h d -> (b s) h d"),
cu_seqlens_q=cu_seqlens_q,
cu_seqlens_k=None, # KV comes from the paged cache via seqused_k
seqused_k=cache_seqlens,
page_table=page_table,
causal=True,
num_splits=1,
ver=4,
)
out = rearrange(out_unpad, "(b s) h d -> b s h d", b=batch_size)
# Decode enters through the flash_attn_with_kvcache wrapper; it must
# thread qv/num_splits down to the same varlen kernel call bit-for-bit.
out_kvcache = flash_attn_with_kvcache(
q=rearrange(q, "b s h d -> (b s) h d"),
k_cache=k_cache_paged,
v_cache=v_cache_paged,
qv=rearrange(qv, "b s h d -> (b s) h d"),
page_table=page_table,
cache_seqlens=cache_seqlens,
cu_seqlens_q=cu_seqlens_q,
max_seqlen_q=seqlen_q,
causal=True,
num_splits=1,
ver=4,
)
assert torch.equal(out_kvcache, out_unpad)
key_padding_mask = rearrange(
torch.arange(seqlen_k, device=device), "s -> 1 s"
) < rearrange(cache_seqlens, "b -> b 1")
k_rep = repeat(k_cache, "b s h d -> b s (h g) d", g=nheads // nheads_k)
v_rep = repeat(v_cache, "b s h d -> b s (h g) d", g=nheads // nheads_k)
out_ref, _ = attention_ref(
q, k_rep, v_rep, None, key_padding_mask, causal=True, qv=qv
)
out_pt, _ = attention_ref(
q,
k_rep,
v_rep,
None,
key_padding_mask,
causal=True,
qv=qv,
upcast=False,
reorder_ops=True,
)
print(f"Output max diff: {(out - out_ref).abs().max().item()}")
print(f"Pytorch max diff: {(out_pt - out_ref).abs().max().item()}")
assert (out - out_ref).abs().max().item() <= 2 * (
out_pt - out_ref
).abs().max().item() + 1e-5
assert (out - out_ref).abs().mean().item() <= 1.5 * (
out_pt - out_ref
).abs().mean().item()
if __name__ == "__main__":
sys.exit(pytest.main([__file__, "-v", "-s"]))
@@ -67,6 +67,18 @@ def _filter(batch: ForwardBatch, *, lo: int, hi: int) -> ForwardBatch:
class TestTboFilterBatchMarker(CustomTestCase):
def test_filter_batch_clears_mlp_sync_unpad_fields_on_children(self):
# MLP-sync padding records _original_batch_size/_original_num_tokens
# before TBO splits the batch (prepare_mlp_sync_batch pads first, then
# runs TboForwardBatchPreparer); children carry no restore state — the
# parent performs the post-forward unpad.
parent = _make_target_verify_batch(8)
parent._original_batch_size = 8
parent._original_num_tokens = 8
child = _filter(parent, lo=0, hi=4)
self.assertIsNone(child._original_batch_size)
self.assertIsNone(child._original_num_tokens)
def test_filter_batch_resets_plan_marker_on_children(self):
child = _filter(_make_target_verify_batch(8), lo=0, hi=4)
self.assertEqual(child.batch_size, 4)
@@ -0,0 +1,108 @@
"""Unit tests for the DP-attention MLP-sync pad/unpad round-trip.
``prepare_mlp_sync_batch`` pads per-request tensors (positions / seq_lens /
req_pool_indices) by appending dummy rows after the real ones so all DP ranks
agree on tensor shapes. ``post_forward_mlp_sync_batch`` must slice them back so
post-forward consumers — seeded sampling (which asserts positions rows ==
sampling rows), ngram token-table updates — never see the padding.
Pure dataclass logic — CPU only.
"""
import unittest
from types import SimpleNamespace
from unittest.mock import MagicMock
import torch
from sglang.srt.model_executor.forward_batch_info import ForwardBatch, ForwardMode
from sglang.test.ci.ci_register import register_cpu_ci
from sglang.test.test_utils import CustomTestCase
register_cpu_ci(est_time=5, suite="base-a-test-cpu")
def _mock_model_runner(seq_len_fill_value: int = 1) -> MagicMock:
runner = MagicMock()
runner.attn_backend.get_cuda_graph_seq_len_fill_value.return_value = (
seq_len_fill_value
)
return runner
def _logits_output(num_rows: int) -> SimpleNamespace:
return SimpleNamespace(
next_token_logits=torch.randn(num_rows, 16), hidden_states=None
)
class TestMlpSyncPadUnpad(CustomTestCase):
def test_decode_post_forward_unpads_per_request_tensors(self):
fb = ForwardBatch(
forward_mode=ForwardMode.DECODE,
batch_size=3,
input_ids=torch.tensor([11, 12, 13]),
req_pool_indices=torch.tensor([5, 6, 7]),
seq_lens=torch.tensor([7, 8, 9]),
out_cache_loc=torch.tensor([0, 1, 2]),
seq_lens_sum=24,
positions=torch.tensor([6, 7, 8]),
seq_lens_cpu=torch.tensor([7, 8, 9]),
lora_ids=[None, None, None],
)
# Mirror the decode arm of prepare_mlp_sync_batch: record the original
# batch size, adopt the synced (padded) one, then pad the inputs.
padded = 5
fb._original_batch_size = fb.batch_size
fb.batch_size = padded
fb._pad_inputs_to_size(_mock_model_runner(), num_tokens=padded, bs=padded)
# Padding appends dummy rows after the real ones.
self.assertEqual(fb.positions.shape[0], padded)
self.assertEqual(fb.seq_lens.shape[0], padded)
self.assertEqual(fb.req_pool_indices.shape[0], padded)
torch.testing.assert_close(fb.positions[:3], torch.tensor([6, 7, 8]))
logits_output = _logits_output(padded)
fb.post_forward_mlp_sync_batch(logits_output)
self.assertEqual(fb.batch_size, 3)
torch.testing.assert_close(fb.positions, torch.tensor([6, 7, 8]))
torch.testing.assert_close(fb.seq_lens, torch.tensor([7, 8, 9]))
torch.testing.assert_close(fb.req_pool_indices, torch.tensor([5, 6, 7]))
torch.testing.assert_close(fb.seq_lens_cpu, torch.tensor([7, 8, 9]))
self.assertEqual(logits_output.next_token_logits.shape[0], 3)
# Seeded sampling asserts positions rows == sampled (real) rows.
self.assertEqual(fb.positions.shape[0], fb.batch_size)
def test_extend_post_forward_unpads_positions(self):
fb = ForwardBatch(
forward_mode=ForwardMode.EXTEND,
batch_size=2,
input_ids=torch.arange(7),
req_pool_indices=torch.tensor([1, 2]),
seq_lens=torch.tensor([3, 4]),
out_cache_loc=torch.arange(7),
seq_lens_sum=7,
positions=torch.tensor([0, 1, 2, 0, 1, 2, 3]),
seq_lens_cpu=torch.tensor([3, 4]),
lora_ids=[None, None],
)
# Extend keeps batch_size; only token-level tensors get padded.
fb._original_batch_size = fb.batch_size
fb._pad_inputs_to_size(_mock_model_runner(), num_tokens=10, bs=2)
self.assertEqual(fb.positions.shape[0], 10)
logits_output = _logits_output(10)
fb.post_forward_mlp_sync_batch(logits_output)
torch.testing.assert_close(fb.positions, torch.tensor([0, 1, 2, 0, 1, 2, 3]))
torch.testing.assert_close(fb.seq_lens, torch.tensor([3, 4]))
# sample() derives prefill sampling positions from seq_lens - 1, so the
# row count must match the real request count.
self.assertEqual((fb.seq_lens - 1).shape[0], fb.batch_size)
if __name__ == "__main__":
unittest.main()
@@ -0,0 +1,163 @@
"""Unit tests for the EAGLE verify coins (_verify_coins / _seeded_verify_coins).
Locks the deterministic-coin contract behind seeded speculative sampling:
identical (seed, seq_lens) inputs produce bitwise-identical coins, distinct
seeds diverge, the column split (first draft_token_num columns -> rejection
coins, last column -> final-sampling coin) holds, unseeded requests keep
torch.rand, and the float32 conversion never emits a coin of exactly 1.0
(the sampling kernels expect half-open [0, 1) coins — a 1.0 coin walks past
the final CDF bucket and can return a zero-probability token).
Requires a GPU: the coins hash through the murmur_hash32 Triton kernel.
"""
import unittest
from types import SimpleNamespace
from unittest.mock import patch
import torch
from sglang.srt.speculative.eagle_utils import _seeded_verify_coins, _verify_coins
from sglang.test.ci.ci_register import register_cuda_ci
from sglang.test.test_utils import CustomTestCase
register_cuda_ci(est_time=20, stage="base-b", runner_config="1-gpu-small")
DRAFT_TOKEN_NUM = 4
def _coins(seeds, seq_lens):
device = "cuda"
return _seeded_verify_coins(
sampling_seed=torch.tensor(seeds, device=device, dtype=torch.int64),
seq_lens=torch.tensor(seq_lens, device=device, dtype=torch.int64),
draft_token_num=DRAFT_TOKEN_NUM,
device=device,
)
class TestSeededVerifyCoins(CustomTestCase):
def test_seeded_coins_are_reproducible(self):
coins_a, final_a = _coins([12345, 67890, 12345], [7, 9, 7])
coins_b, final_b = _coins([12345, 67890, 12345], [7, 9, 7])
self.assertEqual(coins_a.shape, (3, DRAFT_TOKEN_NUM))
self.assertEqual(final_a.shape, (3,))
self.assertTrue(torch.equal(coins_a, coins_b))
self.assertTrue(torch.equal(final_a, final_b))
# Same (seed, seq_len) pair hashes to the same coins regardless of row.
self.assertTrue(torch.equal(coins_a[0], coins_a[2]))
self.assertEqual(final_a[0].item(), final_a[2].item())
# Coins live in [0, 1).
self.assertTrue(bool((coins_a >= 0).all() and (coins_a < 1).all()))
self.assertTrue(bool((final_a >= 0).all() and (final_a < 1).all()))
def test_distinct_seeds_or_positions_diverge(self):
coins, final = _coins([12345, 67890, 12345], [7, 9, 11])
self.assertFalse(torch.equal(coins[0], coins[1])) # different seed
self.assertFalse(torch.equal(coins[0], coins[2])) # different seq_len
def test_column_split_maps_rejection_then_final(self):
# Structured hash: hashed[i, j] = i * 1000 + j, so each coin names its
# (row, column) origin. Locks the column-space contract: columns
# [0, draft_token_num) become the per-draft rejection coins and column
# draft_token_num becomes the final-sampling coin.
umax = torch.iinfo(torch.uint32).max
def _structured_hash(seed, positions, col_indices):
rows = torch.arange(seed.shape[0], device=seed.device).unsqueeze(1)
return (rows * 1000 + col_indices.unsqueeze(0)).to(torch.uint32)
with patch(
"sglang.kernels.ops.sampling.murmur_hash.murmur_hash32",
side_effect=_structured_hash,
):
coins, final = _coins([1, 2], [3, 4])
def _expected(row, col):
return (
torch.tensor(row * 1000 + col, dtype=torch.float64)
.div(umax)
.to(torch.float32)
.item()
)
for row in range(2):
for col in range(DRAFT_TOKEN_NUM):
self.assertEqual(coins[row, col].item(), _expected(row, col))
self.assertEqual(final[row].item(), _expected(row, DRAFT_TOKEN_NUM))
def test_unseeded_requests_keep_torch_rand(self):
device = "cuda"
kwargs = dict(
sampling_info=SimpleNamespace(sampling_seed=None),
seq_lens=torch.tensor([3, 4, 5], device=device, dtype=torch.int64),
draft_token_num=DRAFT_TOKEN_NUM,
candidates=torch.zeros(
(3, DRAFT_TOKEN_NUM), device=device, dtype=torch.int64
),
device=device,
)
with patch(
"sglang.kernels.ops.sampling.murmur_hash.murmur_hash32"
) as mock_hash:
coins_a, final_a = _verify_coins(**kwargs)
coins_b, final_b = _verify_coins(**kwargs)
mock_hash.assert_not_called()
self.assertEqual(coins_a.shape, (3, DRAFT_TOKEN_NUM))
self.assertEqual(final_a.shape, (3,))
self.assertEqual(coins_a.dtype, torch.float32)
# torch.rand draws: two calls must not repeat.
self.assertFalse(torch.equal(coins_a, coins_b))
self.assertFalse(torch.equal(final_a, final_b))
def test_seeded_requests_dispatch_to_seeded_coins(self):
device = "cuda"
seeds = torch.tensor([12345, 67890], device=device, dtype=torch.int64)
seq_lens = torch.tensor([7, 9], device=device, dtype=torch.int64)
coins, final = _verify_coins(
sampling_info=SimpleNamespace(sampling_seed=seeds),
seq_lens=seq_lens,
draft_token_num=DRAFT_TOKEN_NUM,
candidates=torch.zeros(
(2, DRAFT_TOKEN_NUM), device=device, dtype=torch.int64
),
device=device,
)
expected_coins, expected_final = _seeded_verify_coins(
sampling_seed=seeds,
seq_lens=seq_lens,
draft_token_num=DRAFT_TOKEN_NUM,
device=device,
)
self.assertTrue(torch.equal(coins, expected_coins))
self.assertTrue(torch.equal(final, expected_final))
def test_max_hash_clamps_coins_below_one(self):
# The top 129 uint32 hashes round to exactly 1.0 under the float32
# cast; force the worst case and assert the clamp holds the contract.
umax = torch.iinfo(torch.uint32).max
def _all_max_hash(seed, positions, col_indices):
return torch.full(
(seed.shape[0], col_indices.shape[0]),
umax,
dtype=torch.uint32,
device=seed.device,
)
with patch(
"sglang.kernels.ops.sampling.murmur_hash.murmur_hash32",
side_effect=_all_max_hash,
):
coins, final = _coins([1, 2], [3, 4])
self.assertTrue(bool((coins < 1).all()))
self.assertTrue(bool((final < 1).all()))
# Clamped to the largest float32 strictly below one.
self.assertEqual(coins.max().item(), 1.0 - 2**-24)
if __name__ == "__main__":
unittest.main()