whn09 760e3cadc0 Neuron: test suite for new boxes, device-vs-host differential tool
- tests/neuron/setup_trn2.sh: one-shot setup of a fresh Trn2 (venv layered
  on the DLAMI torch-neuronx venv, C++ build, official reference + tokenizer,
  tiny checkpoint, CPU golden).
- tests/neuron/run_all.sh cpu|device|all [stage...]: vendor kernel tests,
  tilelang_ops interface tests (basic-mode stubs reported as skips via
  nie_skip), deep_ep at world size 1/2/4 (gloo) and 2/4/8 on the neuron
  process group, device primitive checks, end-to-end vs golden on CPU and
  on a NeuronCore, and the device diff; PASS/FAIL summary.
- tests/neuron/device/test_device_primitives.py: torch-neuronx behaviours
  the port depends on or works around (fp8 strided-view indexing, uint64,
  1-rank all_to_all, inference-mode version counters, ...).
- examples/neuron/device_diff.py: re-runs every kernel call of a NeuronCore
  run on host copies and ranks kernels by device/host difference.
- Unit tests written during bring-up moved from scratch dirs into
  tests/neuron/{deep_gemm,flash_mla,deep_ep,tile_kernels,sampling}.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-21 09:46:29 +08:00

251 lines
12 KiB
Python

import math
import torch
import torch.distributed as dist
from typing import Optional, Tuple, Union
def get_global_seed() -> int:
return 0
def dispatch(x: Union[torch.Tensor, Tuple[torch.Tensor, torch.Tensor]],
topk_idx: torch.Tensor, topk_weights: Optional[torch.Tensor],
num_max_tokens_per_rank: int, num_experts: int):
"""
The reference implementation of dispatching tokens to experts across multiple ranks.
Not expanded. Sorted by rank and then by token within each rank (i.e. sorted by `src_token_global_idx`).
Arguments:
x: input tokens, `[num_tokens, hidden]` or (`[num_tokens, hidden]`, `[num_tokens, num_sf_packs]`).
topk_idx: top-k expert indices for each token, `[num_tokens, num_topk]`.
topk_weights: top-k weights for each token, can be None, `[num_tokens, num_topk]`.
num_max_tokens_per_rank: the maximum number of tokens per rank, must be `>=` the actual number of
tokens per rank and aligned with DeepEP's `num_max_tokens_per_rank`, since we calculate
`src_token_global_idx = src_rank_idx * num_max_tokens_per_rank + src_token_local_idx`.
num_experts: the total number of experts across all ranks.
Returns:
recv_x, recv_topk_idx, recv_topk_weights: received tokens, top-k indices and top-k weights after
dispatching. Out of range `recv_topk_idx` (i.e. that expert is not on the current rank) are
set to -1.
recv_src_token_idx: received `src_token_global_idx` for each received token.
num_recv_tokens_per_rank: number of received tokens from each rank, `[num_ranks]`.
"""
rank_idx = dist.get_rank()
num_ranks = dist.get_world_size()
assert num_experts % num_ranks == 0
num_experts_per_rank = num_experts // num_ranks
# Unpack SF
use_fp8 = isinstance(x, tuple)
x, sf = x if use_fp8 else (x, None)
num_tokens, hidden = x.size()
num_tokens_, num_topk = topk_idx.size()
assert num_tokens == num_tokens_
num_sf_packs = 0
if sf is not None:
num_tokens__, num_sf_packs = sf.size()
assert num_tokens == num_tokens__
if topk_weights is not None:
num_tokens__, num_topk_ = topk_weights.size()
assert num_tokens == num_tokens__
assert num_topk == num_topk_
# Prepare per-peer send buffers
send_x_list = []
send_sf_list = []
send_topk_idx_list = []
send_topk_weights_list = []
send_src_token_idx_list = []
num_send_tokens_per_rank = torch.zeros((num_ranks, ), dtype=torch.int, device=x.device)
for dst_rank_idx in range(num_ranks):
expert_start_idx = dst_rank_idx * num_experts_per_rank
expert_end_idx = expert_start_idx + num_experts_per_rank
# Get the indices of tokens
mask_to_send = ((expert_start_idx <= topk_idx) & (topk_idx < expert_end_idx)).any(dim=1)
indices_to_send = mask_to_send.nonzero(as_tuple=True)[0]
num_send_tokens_per_rank[dst_rank_idx] = indices_to_send.numel()
# Select the data for tokens
x_to_send = x[indices_to_send]
sf_to_send = sf[indices_to_send] if use_fp8 else None
topk_idx_to_send = topk_idx[indices_to_send]
topk_weights_to_send = topk_weights[indices_to_send]
masked_topk_idx = torch.where((expert_start_idx <= topk_idx_to_send) & (topk_idx_to_send < expert_end_idx),
topk_idx_to_send, torch.full_like(topk_idx_to_send, -1))
send_x_list.append(x_to_send)
send_sf_list.append(sf_to_send)
send_topk_idx_list.append(masked_topk_idx)
send_topk_weights_list.append(topk_weights_to_send)
send_src_token_idx_list.append(indices_to_send)
send_x = torch.cat(send_x_list, dim=0)
send_sf = torch.cat(send_sf_list, dim=0) if use_fp8 else None
send_topk_idx = torch.cat(send_topk_idx_list, dim=0)
send_topk_weights = torch.cat(send_topk_weights_list, dim=0)
send_src_token_idx = torch.cat(send_src_token_idx_list, dim=0).to(torch.int)
send_src_token_idx += rank_idx * num_max_tokens_per_rank
# Exchange size
num_recv_tokens_per_rank = torch.empty((num_ranks, ), dtype=torch.int, device=x.device)
dist.all_to_all_single(num_recv_tokens_per_rank, num_send_tokens_per_rank)
num_recv_tokens = int(num_recv_tokens_per_rank.sum().item())
# Exchange main data
num_send_tokens_per_rank = num_send_tokens_per_rank.tolist()
num_recv_tokens_per_rank = num_recv_tokens_per_rank.tolist()
recv_x = torch.empty((num_recv_tokens, hidden), dtype=x.dtype, device=x.device)
recv_sf = torch.empty((num_recv_tokens, num_sf_packs), dtype=sf.dtype, device=x.device) if use_fp8 else None
recv_topk_idx = torch.empty((num_recv_tokens, num_topk), dtype=topk_idx.dtype, device=x.device)
recv_topk_weights = torch.empty((num_recv_tokens, num_topk), dtype=topk_weights.dtype, device=x.device)
recv_src_token_idx = torch.empty((num_recv_tokens, ), dtype=torch.int, device=x.device)
dist.all_to_all_single(recv_x, send_x, num_recv_tokens_per_rank, num_send_tokens_per_rank)
if use_fp8:
# gloo has no int16 collective: move the SF bytes (bit-exact, same semantics).
dist.all_to_all_single(recv_sf.view(torch.uint8), send_sf.contiguous().view(torch.uint8),
num_recv_tokens_per_rank, num_send_tokens_per_rank)
dist.all_to_all_single(recv_topk_idx, send_topk_idx, num_recv_tokens_per_rank, num_send_tokens_per_rank)
dist.all_to_all_single(recv_topk_weights, send_topk_weights, num_recv_tokens_per_rank, num_send_tokens_per_rank)
dist.all_to_all_single(recv_src_token_idx, send_src_token_idx, num_recv_tokens_per_rank, num_send_tokens_per_rank)
# Mask top-k indices
expert_start_idx = rank_idx * num_experts_per_rank
expert_end_idx = expert_start_idx + num_experts_per_rank
mask = (expert_start_idx <= recv_topk_idx) & (recv_topk_idx < expert_end_idx)
recv_topk_idx = recv_topk_idx - expert_start_idx
recv_topk_idx.masked_fill_(~mask, -1)
# Pack SF
recv_x = (recv_x, recv_sf) if use_fp8 else recv_x
return (recv_x, recv_topk_idx, recv_topk_weights,
recv_src_token_idx, torch.tensor(num_recv_tokens_per_rank, dtype=torch.int))
def generate_pre_combine_data(src_token_global_idx: torch.Tensor,
num_max_tokens_per_rank: int, num_topk: int, hidden: int) -> torch.Tensor:
"""
Generate data needed for combine from `src_token_global_idx`.
Recall that `src_token_global_idx = src_rank_idx * num_max_tokens_per_rank + src_token_local_idx`.
The generated data (denoted as `y`) of the i-th token has a shape of `[num_topk, hidden]`, with
`y[j, k] = sin((token_seeds * P % max_seed + 1) / max_seed * (k + 1) + sin(seed))`
where `P=131071` is a large prime, `token_seeds` is calculated via
`token_seeds = src_token_global_idx[i] * num_topk + j`, and
`max_seed = num_ranks * num_max_tokens_per_rank * num_topk`.
Arguments:
src_token_global_idx: source token global indices, `[num_tokens]`.
Returns:
the generated data, `[num_tokens, num_topk, hidden]`.
"""
num_ranks = dist.get_world_size()
token_seeds = (src_token_global_idx.unsqueeze(1) * num_topk +
torch.arange(num_topk, device=src_token_global_idx.device).unsqueeze(0)) # [num_tokens, num_topk]
max_seed = num_ranks * num_max_tokens_per_rank * num_topk
result = torch.sin(
(((token_seeds * 131071 % max_seed).float() + 1) / max_seed).unsqueeze(-1) *
torch.arange(1, hidden + 1, device=src_token_global_idx.device, dtype=torch.float32).broadcast_to(1, 1, hidden) +
math.sin(float(get_global_seed()))
)
return result.to(torch.bfloat16)
def ordered_accumulate(data: torch.Tensor, initial_value: Optional[torch.Tensor] = None) -> torch.Tensor:
"""
Accumulate `data` in order along the num_topk dimension.
Arguments:
data: data to be accumulated, `[num_tokens, num_topk, hidden]`.
initial_value: initial value for accumulation, `[num_tokens, hidden]`.
Returns:
the result, `[num_tokens, hidden]`.
"""
num_topk = data.shape[1]
if initial_value is None:
result = torch.zeros((data.shape[0], data.shape[2]), dtype=torch.float32, device=data.device)
else:
result = initial_value.clone()
for i in range(num_topk):
result += data[:, i, :].float()
return result.to(data.dtype)
def combine(y: torch.Tensor, topk_idx: torch.Tensor, num_experts: int,
bias: Optional[Union[Tuple[torch.Tensor, ...], torch.Tensor]],
reduce_in_local: bool) -> torch.Tensor:
"""
The reference implementation of (possibly intra-rank reduced) combining tokens.
Arguments:
y: input tokens to be combined, `[num_tokens, num_topk, hidden]`.
topk_idx: `[num_tokens, num_topk]`.
num_experts: the total number of experts across all ranks.
bias: 0, 1 or 2 `[num_tokens, hidden]` final bias added to the output.
reduce_in_local: whether to do reduction within each rank first.
- `True` -> reduce selections landing on the same rank before the global accumulation.
- `False` -> equivalent to `allow_multiple_reduction` being False.
Returns:
the combined result, `[num_tokens, hidden]`.
"""
num_ranks = dist.get_world_size()
num_tokens, hidden = y.shape[0], y.shape[2]
num_topk = y.shape[1]
def grouped_reduce(data_to_reduce: torch.Tensor, group_id: torch.Tensor) -> torch.Tensor:
"""
Perform in-place grouped reduction on `data_to_reduce` according to `group_id`.
The summation within each group is performed in strict order along the `num_topk` dimension.
The result for each group is stored at the rightmost token of that group, and other tokens are
set to zero.
Arguments:
data_to_reduce: data to be reduced, `[num_tokens, num_topk, hidden]`.
group_id: group IDs for each token, `[num_tokens, num_topk]`.
"""
# Shuffle to make tokens with the same group_id contiguous
group_id, src_indices = torch.sort(group_id, dim=-1, stable=True)
# transformed_src_indices[i, j] = i * num_topk + src_indices[i, j]
transformed_src_indices = (
(src_indices + torch.arange(0, num_tokens, device=y.device).unsqueeze(-1) * num_topk).flatten())
data_to_reduce = data_to_reduce.view(-1, hidden)[transformed_src_indices].view(num_tokens, num_topk, hidden)
# Perform segmented reduce within each group
cur_accum_buf = torch.zeros((num_tokens, hidden), dtype=torch.float32, device=y.device)
for i in range(num_topk):
is_segment_break = torch.full((num_tokens, ), True, dtype=torch.bool, device=y.device) \
if i == num_topk - 1 else group_id[:, i] != group_id[:, i + 1]
cur_accum_buf += data_to_reduce[:, i, :].float()
# For one token, if `is_segment_break` is True,
# save the accumulated value and clear the buffer, otherwise, clear `data_to_reduce[:, i, :]`
segment_break_token_indices = torch.where(is_segment_break)[0]
data_to_reduce[segment_break_token_indices, i] = cur_accum_buf[segment_break_token_indices].to(data_to_reduce.dtype)
cur_accum_buf[segment_break_token_indices] = 0.0
non_segment_break_token_indices = torch.where(~is_segment_break)[0]
data_to_reduce[non_segment_break_token_indices, i] = 0.0
# Unshuffle
# noinspection PyShadowingNames
result = torch.empty_like(data_to_reduce)
result.view(-1, hidden)[transformed_src_indices] = data_to_reduce.view(-1, hidden)
return result.view(num_tokens, num_topk, hidden)
num_experts_per_rank = num_experts // num_ranks
if reduce_in_local:
y = grouped_reduce(y, topk_idx // num_experts_per_rank)
bias_sum = None
if isinstance(bias, tuple):
assert len(bias) <= 2
for bias_tensor in bias:
bias_sum = bias_tensor.float() if bias_sum is None else bias_sum + bias_tensor.float()
elif bias is not None:
bias_sum = bias.float()
result = ordered_accumulate(y, bias_sum)
return result