115 lines
4.3 KiB
Python
115 lines
4.3 KiB
Python
import torch
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import xspeedgate_ops
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def int8_mqa_logits(
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q: torch.Tensor,
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kv: tuple[torch.Tensor, torch.Tensor],
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weights: torch.Tensor,
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cu_seqlen_ks: torch.Tensor,
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cu_seqlen_ke: torch.Tensor,
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context_q_lens_xpu: torch.Tensor,
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context_q_lens_cpu: torch.Tensor,
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context_k_lens_xpu: torch.Tensor,
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context_k_lens_cpu: torch.Tensor,
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) -> torch.Tensor:
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"""Compute FP8 MQA logits for a single sequence without KV paging.
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Args:
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q: Query tensor of shape [M, H, D]. Casted to
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`torch.float8_e4m3fn` by caller.
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kv: Tuple `(k_fp8, k_scales)` where `k_fp8` has shape [N, D] with
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dtype `torch.float8_e4m3fn` and `k_scales` has shape [N] (or
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[N, 1]) with dtype `torch.float32`.
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weights: weights of shape [M, H], dtype `torch.float32`.
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cu_seqlen_ks: Start indices (inclusive) for valid K per query position,
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shape [M], dtype int32.
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cu_seqlen_ke: End indices (exclusive) for valid K per query position,
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shape [M], dtype int32.
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Returns:
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Logits tensor of shape [M, N], dtype `torch.float32`.
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"""
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seq_len_q, seq_len_kv =q.shape[0], kv[0].shape[0]
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logits = torch.empty((seq_len_q, seq_len_kv), dtype=torch.float32, device=q.device)
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torch.ops._C.I8_mqa_logits(
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q=q,
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fused_kv_cache=kv,
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weights=weights,
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context_q_lens=(context_q_lens_cpu, context_q_lens_xpu),
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context_k_lens=(context_k_lens_cpu, context_k_lens_xpu),
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logits=logits,
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clean_logits=True,
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use_xfa_boost=False,
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)
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# mask参考 https://github.com/vllm-project/vllm/blob/v0.11.0/tests/kernels/attention/test_deepgemm_attention.py 的_ref_fp8_mqa_logits函数的实现
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torch.ops.xspeedgate_ops.mask_for_I8_mqa_logits(
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seq_len_kv=seq_len_kv,
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cu_seqlen_ks=cu_seqlen_ks,
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cu_seqlen_ke=cu_seqlen_ke,
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logits=logits,
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)
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return logits
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def int8_paged_mqa_logits(
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q_fp8: torch.Tensor,
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kv_cache_fp8: torch.Tensor,
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weights: torch.Tensor,
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context_lens: torch.Tensor,
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context_lens_cpu: torch.Tensor,
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block_tables: torch.Tensor,
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schedule_metadata: torch.Tensor,
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max_model_len: int,
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) -> torch.Tensor:
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"""Compute FP8 MQA logits using paged KV-cache.
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Args:
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q_fp8: Query tensor of shape [B, next_n, H, D]. Casted to
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`torch.float8_e4m3fn` by caller.
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kv_cache_fp8: Paged KV-cache in packed FP8+scale layout with shape
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[num_blocks, block_size, 1, D+4], dtype `torch.uint8`. The last
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4 bytes per (block,pos) store the `float` dequant scale.
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weights: Tensor of shape [B * next_n, H], dtype `torch.float32`.
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context_lens: Tensor of shape [B], dtype int32; effective context length
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for each batch element.
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block_tables: Tensor of shape [B, max_blocks], dtype int32; maps logical
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block indices to physical blocks in the paged cache.
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schedule_metadata: Returned by `get_paged_mqa_logits_metadata`;
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used to distribute work across SMs.
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max_model_len: Maximum sequence length used to size the logits output.
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Returns:
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Logits tensor of shape [B * next_n, max_model_len], dtype
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`torch.float32`.
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"""
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batch_size, next_n, _, D = q_fp8.shape
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num_blocks, block_size, _, _ = kv_cache_fp8.shape
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kv_cache_fp8 = kv_cache_fp8.view(num_blocks, -1)
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k_val = kv_cache_fp8[:, :block_size * D].view(torch.int8)
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k_val = k_val.view(-1, block_size, 1, D)
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block_indices = block_tables.flatten()
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k_scale = kv_cache_fp8[block_indices, block_size * D:].view(-1, 4).view(torch.float32)
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k_scale = k_scale.view(-1, max_model_len)
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kv_cache = [k_val, k_scale]
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weights = weights.view(batch_size,next_n,-1)
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logits = torch.empty((batch_size, next_n, max_model_len), dtype=torch.float32, device=q_fp8.device)
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torch.ops._C.I8_paged_mqa_logits(
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q=q_fp8,
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fused_kv_cache=kv_cache,
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weights=weights,
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context_lens=[context_lens_cpu, context_lens],
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block_table=block_tables,
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max_context_len=max_model_len,
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clean_logits=True,
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out=logits,
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use_xfa_boost=False
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)
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logits = logits.view(-1, max_model_len)
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return logits |