[MM][Perf] Minor Optimization on Qwen3-VL fast_pos_embed_interpolate (#25337)

Signed-off-by: Roger Wang <hey@rogerw.io>
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Roger Wang 2025-09-21 04:05:20 -07:00 committed by GitHub
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@ -270,6 +270,7 @@ class Qwen3_VisionTransformer(nn.Module):
self.temporal_patch_size = vision_config.temporal_patch_size self.temporal_patch_size = vision_config.temporal_patch_size
self.deepstack_visual_indexes = vision_config.deepstack_visual_indexes self.deepstack_visual_indexes = vision_config.deepstack_visual_indexes
self.use_data_parallel = use_data_parallel self.use_data_parallel = use_data_parallel
self.num_grid_per_side = int(self.num_position_embeddings**0.5)
# NOTE: This is used for creating empty tensor for all_gather for # NOTE: This is used for creating empty tensor for all_gather for
# DP ViT. Here out_hidden_size is enlarged due to deepstack # DP ViT. Here out_hidden_size is enlarged due to deepstack
@ -377,82 +378,68 @@ class Qwen3_VisionTransformer(nn.Module):
rotary_pos_emb = rotary_pos_emb_full[pos_ids].flatten(1) rotary_pos_emb = rotary_pos_emb_full[pos_ids].flatten(1)
return rotary_pos_emb return rotary_pos_emb
def fast_pos_embed_interpolate(self, grid_thw): def fast_pos_embed_interpolate(self,
num_grid_per_side = int(self.num_position_embeddings**0.5) grid_thw: list[list[int]]) -> torch.Tensor:
idx_list = [[] for _ in range(4)] num_grid_per_side = self.num_grid_per_side
weight_list = [[] for _ in range(4)] m_size = self.spatial_merge_size
hidden_dim = self.pos_embed.embedding_dim
outputs = []
for t, h, w in grid_thw: for t, h, w in grid_thw:
h_idxs = torch.linspace(0, h_idxs = torch.linspace(0,
num_grid_per_side - 1, num_grid_per_side - 1,
h, h,
dtype=torch.float32) dtype=torch.float32,
device=self.device)
w_idxs = torch.linspace(0, w_idxs = torch.linspace(0,
num_grid_per_side - 1, num_grid_per_side - 1,
w, w,
dtype=torch.float32) dtype=torch.float32,
device=self.device)
h_idxs_floor = h_idxs.to(torch.long) h_floor = h_idxs.to(torch.long)
w_idxs_floor = w_idxs.to(torch.long) w_floor = w_idxs.to(torch.long)
h_idxs_ceil = torch.clamp(h_idxs.to(torch.long) + 1, h_ceil = torch.clamp(h_floor + 1, max=num_grid_per_side - 1)
max=num_grid_per_side - 1) w_ceil = torch.clamp(w_floor + 1, max=num_grid_per_side - 1)
w_idxs_ceil = torch.clamp(w_idxs.to(torch.long) + 1,
max=num_grid_per_side - 1)
dh = h_idxs - h_idxs_floor dh = h_idxs - h_floor
dw = w_idxs - w_idxs_floor dw = w_idxs - w_floor
idx_list[0].extend(((h_idxs_floor * num_grid_per_side)[None].T + w00 = ((1 - dh)[:, None] * (1 - dw)[None, :]).reshape(-1)
w_idxs_floor[None]).flatten().tolist() * t) w01 = ((1 - dh)[:, None] * dw[None, :]).reshape(-1)
idx_list[1].extend(((h_idxs_floor * num_grid_per_side)[None].T + w10 = (dh[:, None] * (1 - dw)[None, :]).reshape(-1)
w_idxs_ceil[None]).flatten().tolist() * t) w11 = (dh[:, None] * dw[None, :]).reshape(-1)
idx_list[2].extend(((h_idxs_ceil * num_grid_per_side)[None].T +
w_idxs_floor[None]).flatten().tolist() * t)
idx_list[3].extend(((h_idxs_ceil * num_grid_per_side)[None].T +
w_idxs_ceil[None]).flatten().tolist() * t)
weight_list[0].extend( idx00 = (h_floor[:, None] * num_grid_per_side +
((1 - dh)[None].T * (1 - dw)[None]).flatten().tolist() * t) w_floor[None, :]).reshape(-1)
weight_list[1].extend( idx01 = (h_floor[:, None] * num_grid_per_side +
((1 - dh)[None].T * dw[None]).flatten().tolist() * t) w_ceil[None, :]).reshape(-1)
weight_list[2].extend( idx10 = (h_ceil[:, None] * num_grid_per_side +
(dh[None].T * (1 - dw)[None]).flatten().tolist() * t) w_floor[None, :]).reshape(-1)
weight_list[3].extend( idx11 = (h_ceil[:, None] * num_grid_per_side +
(dh[None].T * dw[None]).flatten().tolist() * t) w_ceil[None, :]).reshape(-1)
device = self.pos_embed.weight.device indices = torch.stack([idx00, idx01, idx10, idx11], dim=0)
dtype = self.pos_embed.weight.dtype weights = torch.stack([w00, w01, w10, w11],
dim=0).to(dtype=self.dtype,
device=self.device)
weights = weights.unsqueeze(-1)
p0 = self.pos_embed( embeds = self.pos_embed(indices)
torch.tensor( weighted_embeds = embeds * weights
idx_list[0], dtype=torch.long, device=device)) * torch.tensor( p0, p1, p2, p3 = weighted_embeds.unbind(dim=0)
weight_list[0], dtype=dtype, device=device)[:, None] combined = p0 + p1 + p2 + p3
p1 = self.pos_embed(
torch.tensor(
idx_list[1], dtype=torch.long, device=device)) * torch.tensor(
weight_list[1], dtype=dtype, device=device)[:, None]
p2 = self.pos_embed(
torch.tensor(
idx_list[2], dtype=torch.long, device=device)) * torch.tensor(
weight_list[2], dtype=dtype, device=device)[:, None]
p3 = self.pos_embed(
torch.tensor(
idx_list[3], dtype=torch.long, device=device)) * torch.tensor(
weight_list[3], dtype=dtype, device=device)[:, None]
patch_pos_embeds = p0 + p1 + p2 + p3 combined = combined.view(h * w, hidden_dim)
patch_pos_embeds = patch_pos_embeds.split( repeated = combined.unsqueeze(0).expand(t, -1, -1).contiguous()
[t * h * w for t, h, w in grid_thw]) repeated = repeated.view(t, h // m_size, m_size, w // m_size,
patch_pos_embeds_permute = [] m_size, hidden_dim)
m_size = self.spatial_merge_size repeated = repeated.permute(0, 1, 3, 2, 4,
for pos_embed, (t, h, w) in zip(patch_pos_embeds, grid_thw): 5).reshape(-1, hidden_dim)
pos_embed = pos_embed.view(t, h // m_size, m_size, w // m_size, outputs.append(repeated)
m_size, -1).permute(0, 1, 3, 2, 4,
5).flatten(0, 4) return torch.cat(outputs, dim=0)
patch_pos_embeds_permute.append(pos_embed)
patch_pos_embeds = torch.cat(patch_pos_embeds_permute)
return patch_pos_embeds
def compute_attn_mask_seqlen( def compute_attn_mask_seqlen(
self, self,
@ -477,12 +464,9 @@ class Qwen3_VisionTransformer(nn.Module):
hidden_states = hidden_states + pos_embeds hidden_states = hidden_states + pos_embeds
rotary_pos_emb = self.rot_pos_emb(grid_thw) rotary_pos_emb = self.rot_pos_emb(grid_thw)
if isinstance(grid_thw, list): grid_thw_tensor = torch.tensor(grid_thw,
grid_thw_tensor = torch.tensor(grid_thw, device=self.device,
device=hidden_states.device, dtype=torch.int32)
dtype=torch.int32)
else:
grid_thw_tensor = grid_thw
cu_seqlens = torch.repeat_interleave( cu_seqlens = torch.repeat_interleave(
grid_thw_tensor[:, 1] * grid_thw_tensor[:, 2], grid_thw_tensor[:, 1] * grid_thw_tensor[:, 2],
@ -1224,7 +1208,8 @@ class Qwen3VLForConditionalGeneration(nn.Module, SupportsMultiModal,
grid_thw_list, grid_thw_list,
rope_type="rope_3d") rope_type="rope_3d")
else: else:
image_embeds = self.visual(pixel_values, grid_thw=grid_thw) image_embeds = self.visual(pixel_values,
grid_thw=grid_thw_list)
# Split concatenated embeddings for each image item. # Split concatenated embeddings for each image item.
# Using prod on grid_thw_list instead of grid_thw.prod avoids CUDA sync # Using prod on grid_thw_list instead of grid_thw.prod avoids CUDA sync
@ -1526,4 +1511,4 @@ class Qwen3VLForConditionalGeneration(nn.Module, SupportsMultiModal,
language_model="language_model", language_model="language_model",
connector="model.visual.merger", connector="model.visual.merger",
tower_model="model.visual.", tower_model="model.visual.",
) )