| |
| from typing import Tuple, Optional |
| from dataclasses import dataclass |
|
|
| import cutlass |
| import cutlass.cute as cute |
|
|
| from flash_attn.cute.seqlen_info import SeqlenInfoQK |
|
|
|
|
| @dataclass(frozen=True) |
| class BlockInfo: |
| m_block_size: cutlass.Constexpr[int] |
| n_block_size: cutlass.Constexpr[int] |
| is_causal: cutlass.Constexpr[bool] |
| is_local: cutlass.Constexpr[bool] = False |
| window_size_left: Optional[cutlass.Int32] = None |
| window_size_right: Optional[cutlass.Int32] = None |
| qhead_per_kvhead_packgqa: cutlass.Constexpr[int] = 1 |
|
|
| @cute.jit |
| def get_n_block_min_max( |
| self, seqlen_info: SeqlenInfoQK, m_block: cutlass.Int32 |
| ) -> Tuple[cutlass.Int32, cutlass.Int32]: |
| n_block_max = cute.ceil_div(seqlen_info.seqlen_k, self.n_block_size) |
| if cutlass.const_expr( |
| self.is_causal or (self.is_local and self.window_size_right is not None) |
| ): |
| m_idx_max = (m_block + 1) * self.m_block_size |
| if cutlass.const_expr(self.qhead_per_kvhead_packgqa > 1): |
| m_idx_max = cute.ceil_div(m_idx_max, self.qhead_per_kvhead_packgqa) |
| n_idx = m_idx_max + seqlen_info.seqlen_k - seqlen_info.seqlen_q |
| n_idx_right = n_idx if cutlass.const_expr(self.is_causal) else n_idx + self.window_size_right |
| n_block_max = min(n_block_max, cute.ceil_div(n_idx_right, self.n_block_size)) |
| n_block_min = 0 |
| if cutlass.const_expr(self.is_local and self.window_size_left is not None): |
| m_idx_min = m_block * self.m_block_size |
| if cutlass.const_expr(self.qhead_per_kvhead_packgqa > 1): |
| m_idx_min = m_idx_min // self.qhead_per_kvhead_packgqa |
| n_idx = m_idx_min + seqlen_info.seqlen_k - seqlen_info.seqlen_q |
| n_idx_left = n_idx - self.window_size_left |
| n_block_min = cutlass.max(n_idx_left // self.n_block_size, 0) |
| return n_block_min, n_block_max |
|
|
| @cute.jit |
| def get_n_block_min_causal_local_mask( |
| self, |
| seqlen_info: SeqlenInfoQK, |
| m_block: cutlass.Int32, |
| n_block_min: cutlass.Int32, |
| ) -> cutlass.Int32: |
| """If we have separate iterations with causal or local masking at the start, where do we stop""" |
| m_idx_min = m_block * self.m_block_size |
| if cutlass.const_expr(self.qhead_per_kvhead_packgqa > 1): |
| m_idx_min = m_idx_min // self.qhead_per_kvhead_packgqa |
| n_idx = m_idx_min + seqlen_info.seqlen_k - seqlen_info.seqlen_q |
| n_idx_right = ( |
| n_idx |
| if cutlass.const_expr(not self.is_local or self.window_size_right is None) |
| else n_idx + self.window_size_right |
| ) |
| return cutlass.max(n_block_min, n_idx_right // self.n_block_size) |
|
|
| @cute.jit |
| def get_n_block_min_before_local_mask( |
| self, |
| seqlen_info: SeqlenInfoQK, |
| m_block: cutlass.Int32, |
| n_block_min: cutlass.Int32, |
| ) -> cutlass.Int32: |
| """If we have separate iterations with local masking at the end, where do we stop the non-masked iterations""" |
| if cutlass.const_expr(not self.is_local or self.window_size_left is None): |
| return n_block_min |
| else: |
| m_idx_max = (m_block + 1) * self.m_block_size |
| if cutlass.const_expr(self.qhead_per_kvhead_packgqa > 1): |
| m_idx_max = cute.ceil_div(m_idx_max, self.qhead_per_kvhead_packgqa) |
| n_idx = m_idx_max + seqlen_info.seqlen_k - seqlen_info.seqlen_q |
| n_idx_left = n_idx - self.window_size_left |
| return cutlass.max(n_block_min, cute.ceil_div(n_idx_left, self.n_block_size)) |
|
|
