diff --git a/matrixgame/model_variants/matrixgame_dit_src/attenion.py b/matrixgame/model_variants/matrixgame_dit_src/attenion.py
new file mode 100644
index 0000000..8667c00
--- /dev/null
+++ b/matrixgame/model_variants/matrixgame_dit_src/attenion.py
@@ -0,0 +1,232 @@
+import importlib.metadata
+import math
+
+import torch
+import torch.nn as nn
+import torch.nn.functional as F
+
+try:
+    from flash_attn_interface import flash_attn_varlen_func
+except ImportError:
+    flash_attn_varlen_func = None
+
+
+MEMORY_LAYOUT = {
+    "flash": (
+        lambda x: x.view(x.shape[0] * x.shape[1], *x.shape[2:]),
+        lambda x: x,
+    ),
+    "torch": (
+        lambda x: x.transpose(1, 2),
+        lambda x: x.transpose(1, 2),
+    ),
+    "vanilla": (
+        lambda x: x.transpose(1, 2),
+        lambda x: x.transpose(1, 2),
+    ),
+}
+
+
+def get_cu_seqlens(text_mask, img_len):
+    """Calculate cu_seqlens_q, cu_seqlens_kv using text_mask and img_len
+
+    Args:
+        text_mask (torch.Tensor): the mask of text
+        img_len (int): the length of image
+
+    Returns:
+        torch.Tensor: the calculated cu_seqlens for flash attention
+    """
+    batch_size = text_mask.shape[0]
+    text_len = text_mask.sum(dim=1)
+    max_len = text_mask.shape[1] + img_len
+
+    cu_seqlens = torch.zeros([2 * batch_size + 1], dtype=torch.int32, device="cuda")
+
+    for i in range(batch_size):
+        s = text_len[i] + img_len
+        s1 = i * max_len + s
+        s2 = (i + 1) * max_len
+        cu_seqlens[2 * i + 1] = s1
+        cu_seqlens[2 * i + 2] = s2
+
+    return cu_seqlens
+
+def get_cu_seqlens_(text_mask, img_len):
+    """Calculate cu_seqlens_q, cu_seqlens_kv using text_mask and img_len
+
+    Args:
+        text_mask (torch.Tensor): the mask of text
+        img_len (int): the length of image
+
+    Returns:
+        torch.Tensor: the calculated cu_seqlens for flash attention
+    """
+    batch_size = text_mask.shape[0]
+    text_len = 0
+    max_len = img_len
+
+    cu_seqlens = torch.zeros([2 * batch_size + 1], dtype=torch.int32, device="cuda")
+
+    for i in range(batch_size):
+        s = text_len + img_len
+        s1 = i * max_len + s
+        s2 = (i + 1) * max_len
+        cu_seqlens[2 * i + 1] = s1
+        cu_seqlens[2 * i + 2] = s2
+
+    return cu_seqlens
+
+def attention(
+    q,
+    k,
+    v,
+    mode="flash",
+    drop_rate=0,
+    attn_mask=None,
+    causal=False,
+    cu_seqlens_q=None,
+    cu_seqlens_kv=None,
+    max_seqlen_q=None,
+    max_seqlen_kv=None,
+    batch_size=1,
+):
+    """
+    Perform QKV self attention.
+
+    Args:
+        q (torch.Tensor): Query tensor with shape [b, s, a, d], where a is the number of heads.
+        k (torch.Tensor): Key tensor with shape [b, s1, a, d]
+        v (torch.Tensor): Value tensor with shape [b, s1, a, d]
+        mode (str): Attention mode. Choose from 'self_flash', 'cross_flash', 'torch', and 'vanilla'.
+        drop_rate (float): Dropout rate in attention map. (default: 0)
+        attn_mask (torch.Tensor): Attention mask with shape [b, s1] (cross_attn), or [b, a, s, s1] (torch or vanilla).
+            (default: None)
+        causal (bool): Whether to use causal attention. (default: False)
+        cu_seqlens_q (torch.Tensor): dtype torch.int32. The cumulative sequence lengths of the sequences in the batch,
+            used to index into q.
+        cu_seqlens_kv (torch.Tensor): dtype torch.int32. The cumulative sequence lengths of the sequences in the batch,
+            used to index into kv.
+        max_seqlen_q (int): The maximum sequence length in the batch of q.
+        max_seqlen_kv (int): The maximum sequence length in the batch of k and v.
+
+    Returns:
+        torch.Tensor: Output tensor after self attention with shape [b, s, ad]
+    """
+    pre_attn_layout, post_attn_layout = MEMORY_LAYOUT[mode]
+    q = pre_attn_layout(q)
+    k = pre_attn_layout(k)
+    v = pre_attn_layout(v)
+
+    if mode == "torch":
+        if attn_mask is not None and attn_mask.dtype != torch.bool:
+            attn_mask = attn_mask.to(q.dtype)
+        x = F.scaled_dot_product_attention(
+            q, k, v, attn_mask=attn_mask, dropout_p=drop_rate, is_causal=causal
+        )
+    elif mode == "flash":
+        x, _ = flash_attn_varlen_func(
+            q,
+            k,
+            v,
+            cu_seqlens_q,
+            cu_seqlens_kv,
+            max_seqlen_q,
+            max_seqlen_kv,
+        )
+        # x with shape [(bxs), a, d]
+        x = x.view(
+            batch_size, max_seqlen_q, x.shape[-2], x.shape[-1]
+        )  # reshape x to [b, s, a, d]
+    elif mode == "vanilla":
+        scale_factor = 1 / math.sqrt(q.size(-1))
+
+        b, a, s, _ = q.shape
+        s1 = k.size(2)
+        attn_bias = torch.zeros(b, a, s, s1, dtype=q.dtype, device=q.device)
+        if causal:
+            # Only applied to self attention
+            assert (
+                attn_mask is None
+            ), "Causal mask and attn_mask cannot be used together"
+            temp_mask = torch.ones(b, a, s, s, dtype=torch.bool, device=q.device).tril(
+                diagonal=0
+            )
+            attn_bias.masked_fill_(temp_mask.logical_not(), float("-inf"))
+            attn_bias.to(q.dtype)
+
+        if attn_mask is not None:
+            if attn_mask.dtype == torch.bool:
+                attn_bias.masked_fill_(attn_mask.logical_not(), float("-inf"))
+            else:
+                attn_bias += attn_mask
+
+        # TODO: Maybe force q and k to be float32 to avoid numerical overflow
+        attn = (q @ k.transpose(-2, -1)) * scale_factor
+        attn += attn_bias
+        attn = attn.softmax(dim=-1)
+        attn = torch.dropout(attn, p=drop_rate, train=True)
+        x = attn @ v
+    else:
+        raise NotImplementedError(f"Unsupported attention mode: {mode}")
+
+    x = post_attn_layout(x)
+    b, s, a, d = x.shape
+    out = x.reshape(b, s, -1)
+    return out
+
+
+def parallel_attention(
+    hybrid_seq_parallel_attn,
+    q,
+    k,
+    v,
+    img_q_len,
+    img_kv_len,
+    cu_seqlens_q,
+    cu_seqlens_kv
+):
+    attn1 = hybrid_seq_parallel_attn(
+        None,
+        q[:, :img_q_len, :, :],
+        k[:, :img_kv_len, :, :],
+        v[:, :img_kv_len, :, :],
+        dropout_p=0.0,
+        causal=False,
+        joint_tensor_query=q[:,img_q_len:cu_seqlens_q[1]],
+        joint_tensor_key=k[:,img_kv_len:cu_seqlens_kv[1]],
+        joint_tensor_value=v[:,img_kv_len:cu_seqlens_kv[1]],
+        joint_strategy="rear",
+    )
+    if flash_attn.__version__ >= '2.7.0':
+        attn2, *_ = _flash_attn_forward(
+            q[:,cu_seqlens_q[1]:],
+            k[:,cu_seqlens_kv[1]:],
+            v[:,cu_seqlens_kv[1]:],
+            dropout_p=0.0,
+            softmax_scale=q.shape[-1] ** (-0.5),
+            causal=False,
+            window_size_left=-1,
+            window_size_right=-1,
+            softcap=0.0,
+            alibi_slopes=None,
+            return_softmax=False,
+        )
+    else:
+        attn2, *_ = _flash_attn_forward(
+            q[:,cu_seqlens_q[1]:],
+            k[:,cu_seqlens_kv[1]:],
+            v[:,cu_seqlens_kv[1]:],
+            dropout_p=0.0,
+            softmax_scale=q.shape[-1] ** (-0.5),
+            causal=False,
+            window_size=(-1, -1),
+            softcap=0.0,
+            alibi_slopes=None,
+            return_softmax=False,
+        )
+    attn = torch.cat([attn1, attn2], dim=1)
+    b, s, a, d = attn.shape
+    attn = attn.reshape(b, s, -1)
+
+    return attn