diff --git a/dsv4/kernels/attention/fmha.py b/dsv4/kernels/attention/fmha.py index ffc85a37..2ed27d7e 100644 --- a/dsv4/kernels/attention/fmha.py +++ b/dsv4/kernels/attention/fmha.py @@ -366,10 +366,7 @@ class FmhaKernel: cute.copy(tiled_tmem_store, rP_words, tTMEM_STOREtP) cute.arch.fence_view_async_tmem_store() else: - # SMEM-P: write P to sP using TiledCopy derived from QK MMA. # SMEM-P: write P to sP using coordinate-indexed store. - # Uses tTMEM_LOADcS identity tensor to get (m, k) coordinates - # and maps them to sP's swizzled layout. for j0 in range(32): for j1 in range(4): coord = tTMEM_LOADcS[(j0, 0), j1, 0, 0] @@ -443,7 +440,7 @@ class FmhaKernel: if sfw_idx == 0: _ln2 = Float32(0.6931471805599453) # ln(2) lse_val = cute.math.log(row_sum, fastmath=True) + _row_max_safe * _ln2 - mLSE[0] = lse_val.to(self.q_dtype) + mLSE[0] = lse_val tmem.relinquish_alloc_permit() tmem.free(tmem_ptr) diff --git a/tests/unit/test_d1_tmem_only.py b/tests/unit/test_d1_tmem_only.py new file mode 100644 index 00000000..c195b760 --- /dev/null +++ b/tests/unit/test_d1_tmem_only.py @@ -0,0 +1,71 @@ +"""D1: Test TMEM-P at all head dims (force use_smem_p=False).""" +import torch, math +import cutlass.cute as cute +import cutlass.torch as ct +import cuda.bindings.driver as cuda +from dsv4.kernels.attention.fmha import FmhaKernel + + +def test_tmem_p(hd, n_kv=128): + m = 128 + torch.manual_seed(42) + q = torch.randn(m, hd, 1, dtype=torch.bfloat16, device='cuda') + k = torch.randn(n_kv, hd, 1, dtype=torch.bfloat16, device='cuda') + v = torch.randn(n_kv, hd, dtype=torch.bfloat16, device='cuda') + c = torch.zeros(m, hd, 1, dtype=torch.bfloat16, device='cuda') + + qf = q[:, :, 0].float() + kf = k[:, :, 0].float() + scale = 1.0 / math.sqrt(hd) + attn_max = (qf @ kf.T * scale).max(dim=-1, keepdim=True)[0] + attn_exp = torch.exp(qf @ kf.T * scale - attn_max) + attn_sum = attn_exp.sum(dim=-1, keepdim=True) + ref_unnorm = attn_exp @ v.float() + ref_lse = torch.log(attn_sum.squeeze(-1)) + attn_max.squeeze(-1) + + lse_tensor = torch.zeros(m, 1, 1, dtype=torch.float32, device='cuda') + kernel = FmhaKernel(head_dim=hd, s_k=n_kv, use_smem_p=False) + pv_n_tile = kernel.pv_n_tile + n_pv_tiles = kernel.n_pv_tiles + stream = cuda.CUstream(torch.cuda.current_stream().cuda_stream) + + v_tile = v[:, 0:pv_n_tile].contiguous().unsqueeze(-1) + c_tile = torch.zeros(m, pv_n_tile, 1, dtype=torch.bfloat16, device='cuda') + mQ = ct.from_dlpack(q).mark_layout_dynamic(leading_dim=ct.get_leading_dim(q)) + mK = ct.from_dlpack(k).mark_layout_dynamic(leading_dim=ct.get_leading_dim(k)) + mV = ct.from_dlpack(v_tile).mark_layout_dynamic(leading_dim=ct.get_leading_dim(v_tile)) + mC = ct.from_dlpack(c_tile).mark_layout_dynamic(leading_dim=ct.get_leading_dim(c_tile)) + mLSE = ct.from_dlpack(lse_tensor).mark_layout_dynamic(leading_dim=ct.get_leading_dim(lse_tensor)) + + print(f'hd={hd} TMEM-P: Compiling...', flush=True) + compiled = cute.compile(kernel, mQ, mK, mV, mC, stream, mLSE) + + lse_val = None + for nt in range(n_pv_tiles): + vs, ve = nt * pv_n_tile, (nt + 1) * pv_n_tile + v_t = v[:, vs:ve].contiguous().unsqueeze(-1) + c_tile = torch.zeros(m, pv_n_tile, 1, dtype=torch.bfloat16, device='cuda') + lse_tensor.zero_() + mQ = ct.from_dlpack(q).mark_layout_dynamic(leading_dim=ct.get_leading_dim(q)) + mK = ct.from_dlpack(k).mark_layout_dynamic(leading_dim=ct.get_leading_dim(k)) + mV = ct.from_dlpack(v_t).mark_layout_dynamic(leading_dim=ct.get_leading_dim(v_t)) + mC = ct.from_dlpack(c_tile).mark_layout_dynamic(leading_dim=ct.get_leading_dim(c_tile)) + mLSE = ct.from_dlpack(lse_tensor).mark_layout_dynamic(leading_dim=ct.get_leading_dim(lse_tensor)) + compiled(mQ, mK, mV, mC, stream, mLSE) + torch.cuda.synchronize() + c[:, vs:ve, :] = c_tile + if nt == 0: + lse_val = lse_tensor[0, 0, 0].item() + + out = c[:, :, 0].float() + cos = torch.nn.functional.cosine_similarity(out.flatten().unsqueeze(0), ref_unnorm.flatten().unsqueeze(0)).item() + ref_lse_val = ref_lse[0].item() + lse_err = abs(lse_val - ref_lse_val) if lse_val is not None else float('inf') + print(f'hd={hd} TMEM-P: cos {cos:.6f} lse_err {lse_err:.6f} {"PASS" if cos >= 0.99 else "FAIL"}') + return cos + + +if __name__ == '__main__': + print("=== TMEM-P at various head dims ===\n") + for hd in [64, 128, 256]: + test_tmem_p(hd)