| import torch |
| import triton |
| import triton.language as tl |
|
|
| from fla.ops.utils import prepare_chunk_indices |
|
|
|
|
| @triton.heuristics({ |
| 'USE_GATE': lambda args: args['g_cumsum'] is not None, |
| 'IS_VARLEN': lambda args: args['cu_seqlens'] is not None, |
| }) |
| @triton.jit(do_not_specialize=['T']) |
| def parallel_path_fwd_kernel( |
| q, |
| k, |
| v, |
| o, |
| o_new, |
| g_cumsum, |
| w1, |
| w2, |
| scale, |
| L, |
| L_new, |
| M, |
| cu_seqlens, |
| indices, |
| T, |
| G: tl.constexpr, |
| HQ: tl.constexpr, |
| H: tl.constexpr, |
| K: tl.constexpr, |
| V: tl.constexpr, |
| BT: tl.constexpr, |
| BS: tl.constexpr, |
| BK: tl.constexpr, |
| BV: tl.constexpr, |
| USE_GATE: tl.constexpr, |
| IS_VARLEN: tl.constexpr, |
| ): |
| i_t, i_bh = tl.program_id(0), tl.program_id(1) |
| i_b, i_hq = i_bh // HQ, i_bh % HQ |
| i_h = i_hq // G |
|
|
| if IS_VARLEN: |
| i_n, i_t = tl.load(indices + i_t * 2).to(tl.int32), tl.load(indices + i_t * 2 + 1).to(tl.int32) |
| bos, eos = tl.load(cu_seqlens + i_n).to(tl.int32), tl.load(cu_seqlens + i_n + 1).to(tl.int32) |
| T = eos - bos |
| else: |
| i_n = i_b |
| bos, eos = i_n * T, i_n * T + T |
|
|
| p_q = tl.make_block_ptr(q + (bos * HQ + i_hq) * K, (T, K), (HQ*K, 1), (i_t * BT, 0), (BT, BK), (1, 0)) |
| b_q = tl.zeros([BT, BK], dtype=tl.float32) |
| b_q += tl.load(p_q, boundary_check=(0, 1)) |
| sm_scale = scale * 1.44269504 |
| b_o = tl.zeros([BT, BV], dtype=tl.float32) |
| p_o = tl.make_block_ptr(o + (bos * HQ + i_hq) * V, (T, V), (HQ*V, 1), (i_t * BT, 0), (BT, BV), (1, 0)) |
| b_o += tl.load(p_o, boundary_check=(0, 1)) |
|
|
| p_L = tl.make_block_ptr(L + bos * HQ + i_hq, (T, ), (HQ, ), (i_t * BT, ), (BT, ), (0,)) |
| p_M = tl.make_block_ptr(M + bos * HQ + i_hq, (T, ), (HQ, ), (i_t * BT, ), (BT, ), (0,)) |
| b_l = tl.load(p_L, boundary_check=(0,)) |
| b_m = tl.load(p_M, boundary_check=(0,)) |
|
|
| if USE_GATE: |
| p_g_cumsum_q = tl.make_block_ptr(g_cumsum + bos * HQ + i_hq, (T, ), (HQ, ), (i_t * BT, ), (BT, ), (0,)) |
| b_g_cumsum_q = tl.load(p_g_cumsum_q, boundary_check=(0,)) |
| else: |
| b_g_cumsum_q = None |
|
|
| for offset in range((i_t + 1) * BT - 2 * BS, i_t*BT-BS, -BS): |
| p_k = tl.make_block_ptr(k + (bos * H + i_h) * K, (K, T), (1, K*H), (0, offset), (BK, BS), (0, 1)) |
| p_v = tl.make_block_ptr(v + (bos * H + i_h) * V, (T, V), (V*H, 1), (offset, 0), (BS, BV), (1, 0)) |
| p_w1 = tl.make_block_ptr(w1 + (bos * H + i_h) * K, (K, T), (1, K*H), (0, offset), (BK, BS), (0, 1)) |
| p_w2 = tl.make_block_ptr(w2 + (bos * H + i_h) * K, (T, K), (K*H, 1), (offset, 0), (BS, BK), (1, 0)) |
| |
|
|
| b_k = tl.load(p_k, boundary_check=(0, 1)) |
| |
| b_v = tl.load(p_v, boundary_check=(0, 1)) |
| |
| b_w1 = tl.load(p_w1, boundary_check=(0, 1)) |
| b_w2 = tl.load(p_w2, boundary_check=(0, 1)) |
| |
| m_s = i_t * BT + tl.arange(0, BT) >= (offset + BS) |
| b_s = tl.dot(b_q.to(b_k.dtype), b_k) |
|
|
| if USE_GATE: |
| p_g_cumsum_k = tl.make_block_ptr(g_cumsum + (bos * HQ + i_hq), (T, ), (HQ, ), (offset, ), (BS, ), (0,)) |
| b_g_cumsum_k = tl.load(p_g_cumsum_k, boundary_check=(0,)) |
| b_s = b_s + b_g_cumsum_q[:, None] - b_g_cumsum_k[None, :] |
| b_s = tl.where(m_s[:, None], b_s * sm_scale, float("-inf")) |
| b_m_new = tl.maximum(b_m, tl.max(b_s, 1)) |
| alpha = tl.math.exp2(b_m - b_m_new) |
| b_s = tl.math.exp2(b_s - b_m_new[:, None]) |
| b_o *= alpha[:, None] |
| b_l = b_l * alpha + tl.sum(b_s, 1) |
| b_m = b_m_new |
| b_o += tl.dot(b_s.to(b_v.dtype), b_v) |
| b_s2 = tl.dot(b_q.to(b_w1.dtype), b_w1) |
| b_s2 = tl.where(m_s[:, None], b_s2, 0) |
| b_q -= tl.dot(b_s2.to(b_w2.dtype), b_w2) |
|
|
| tl.debug_barrier() |
|
|
| for offset in range(i_t * BT - BS, -BS, -BS): |
| p_k = tl.make_block_ptr(k + (bos * H + i_h) * K, (K, T), (1, K*H), (0, offset), (BK, BS), (0, 1)) |
| p_v = tl.make_block_ptr(v + (bos * H + i_h) * V, (T, V), (V*H, 1), (offset, 0), (BS, BV), (1, 0)) |
| p_w1 = tl.make_block_ptr(w1 + (bos * H + i_h) * K, (K, T), (1, K*H), (0, offset), (BK, BS), (0, 1)) |
| p_w2 = tl.make_block_ptr(w2 + (bos * H + i_h) * K, (T, K), (K*H, 1), (offset, 0), (BS, BK), (1, 0)) |
| |
| b_k = tl.load(p_k, boundary_check=(0, 1)) |
| |
| b_v = tl.load(p_v, boundary_check=(0, 1)) |
| b_w1 = tl.load(p_w1, boundary_check=(0, 1)) |
| b_w2 = tl.load(p_w2, boundary_check=(0, 1)) |
| |
| b_s = tl.dot(b_q.to(b_k.dtype), b_k) |
| if USE_GATE: |
| p_g_cumsum_k = tl.make_block_ptr(g_cumsum + (bos * HQ + i_hq), (T, ), (HQ, ), (offset, ), (BS, ), (0,)) |
| b_g_cumsum_k = tl.load(p_g_cumsum_k, boundary_check=(0,)) |
| b_s = b_s + b_g_cumsum_q[:, None] - b_g_cumsum_k[None, :] |
| b_s = b_s * sm_scale |
| b_m_new = tl.maximum(b_m, tl.max(b_s, 1)) |
| alpha = tl.math.exp2(b_m - b_m_new) |
| b_s = tl.math.exp2(b_s - b_m_new[:, None]) |
| b_o *= alpha[:, None] |
| b_l = b_l * alpha + tl.sum(b_s, 1) |
| b_m = b_m_new |
| b_o += tl.dot(b_s.to(b_v.dtype), b_v) |
| b_s2 = tl.dot(b_q.to(b_w1.dtype), b_w1) |
| b_q -= tl.dot(b_s2.to(b_w2.dtype), b_w2) |
|
|
| b_o = b_o / b_l[:, None] |
| p_o_new = tl.make_block_ptr(o_new + (bos * HQ + i_hq) * V, (T, V), (HQ*V, 1), (i_t*BT, 0), (BT, BV), (1, 0)) |
| tl.store(p_o_new, b_o.to(p_o_new.dtype.element_ty), boundary_check=(0, 1)) |
| b_l = tl.math.log2(b_l) + b_m |
| p_L_new = tl.make_block_ptr(L_new + (bos * HQ + i_hq), (T, ), (HQ, ), (i_t * BT, ), (BT, ), (0,)) |
| tl.store(p_L_new, b_l.to(p_L_new.dtype.element_ty), boundary_check=(0,)) |
|
|
|
|
| def parallel_path_fwd_fn( |
| q, |
| k, |
| v, |
| o, |
| g_cumsum, |
| w1, |
| w2, |
| scale, |
| L, |
| M, |
| cu_seqlens, |
| BT, |
| BS, |
| ): |
| B, T, HQ, K = q.shape |
| V = v.shape[-1] |
| H = k.shape[-2] |
| G = HQ // H |
| indices = prepare_chunk_indices(cu_seqlens, BT) if cu_seqlens is not None else None |
| NT = triton.cdiv(T, BT) if cu_seqlens is None else len(indices) |
| grid = (NT, B * HQ) |
| o_new = torch.empty_like(o, dtype=v.dtype) |
| L_new = torch.empty_like(L) |
|
|
| parallel_path_fwd_kernel[grid]( |
| q=q, |
| k=k, |
| v=v, |
| o=o, |
| o_new=o_new, |
| w1=w1, |
| w2=w2, |
| g_cumsum=g_cumsum, |
| scale=scale, |
| cu_seqlens=cu_seqlens, |
| indices=indices, |
| L=L, |
| L_new=L_new, |
| M=M, |
| T=T, |
| K=K, |
| V=V, |
| BK=triton.next_power_of_2(K), |
| BV=triton.next_power_of_2(V), |
| G=G, |
| HQ=HQ, |
| H=H, |
| BS=BS, |
| BT=BT, |
| num_warps=8 if (BT == 128 and K == 128) else 4, |
| ) |
| return o_new, L_new |
|
|
