From 6e5b4de01a68985f532702abe82f056218ff30c7 Mon Sep 17 00:00:00 2001
From: Mick
Date: Mon, 11 May 2026 13:42:08 +0800
Subject: [PATCH] [diffusion] fix: further align ltx2.3 accuracy with tp
(#24660)
---
.../cookbook/diffusion/LTX/LTX2 & LTX2.3.mdx | 13 +-
.../src/snippets/diffusion/ltx-deployment.jsx | 2 +-
.../runtime/layers/attention/backends/sdpa.py | 21 +-
.../runtime/layers/attention/layer.py | 83 ++++--
.../runtime/models/dits/ltx_2.py | 61 ++--
.../runtime/models/encoders/gemma_3.py | 64 ++---
.../runtime/pipelines/ltx_2_pipeline.py | 1 -
.../executors/parallel_executor.py | 6 +-
.../pipelines_core/stages/denoising_av.py | 12 +-
.../pipelines_core/stages/ltx_2_denoising.py | 262 ++++++++++--------
.../multimodal_gen/runtime/server_args.py | 12 +-
.../test/server/consistency_threshold.json | 18 +-
.../multimodal_gen/test/server/gpu_cases.py | 11 +-
.../test/server/perf_baselines.json | 120 ++++----
.../test/test_consistency_metrics.py | 3 +
.../sglang/multimodal_gen/test/test_utils.py | 57 +++-
16 files changed, 435 insertions(+), 311 deletions(-)
diff --git a/docs_new/cookbook/diffusion/LTX/LTX2 & LTX2.3.mdx b/docs_new/cookbook/diffusion/LTX/LTX2 & LTX2.3.mdx
index 2eaf29650..c73169bc1 100644
--- a/docs_new/cookbook/diffusion/LTX/LTX2 & LTX2.3.mdx
+++ b/docs_new/cookbook/diffusion/LTX/LTX2 & LTX2.3.mdx
@@ -71,7 +71,7 @@ Other deployment flags:
- `--lora-weight-name`: Select the exact safetensors file when the LoRA repository contains multiple weight files.
-For native LTX-2.3 two-stage serving without a user LoRA, `resident` is the fastest high-VRAM path. When you pass `--lora-path`, SGLang still applies the user LoRA during the two-stage switch, so use `resident` on H200-class GPUs for enough VRAM, but do not expect the same premerged-stage2 benefit as the no-user-LoRA path.
+For native LTX-2.3 two-stage serving without a user LoRA, `resident` is the fastest high-VRAM path. LTX-2 still applies the distilled LoRA during the stage switch, so `--ltx2-two-stage-device-mode` is mainly an LTX-2.3 optimization. When you pass `--lora-path`, SGLang still applies the user LoRA during the two-stage switch, so use `resident` on H200-class GPUs for enough VRAM, but do not expect the same premerged-stage2 benefit as the no-user-LoRA path.
### 3.3 Fast multi-GPU presets
@@ -80,11 +80,12 @@ For latency-oriented LTX serving, prefer CFG parallel over sequence parallelism.
| Target | Recommended server flags | Notes |
| --- | --- | --- |
-| 1 high-VRAM GPU | `--ltx2-two-stage-device-mode resident` | Fastest two-stage setup when both DiTs fit. |
-| 1 standard GPU | `--ltx2-two-stage-device-mode snapshot` | Lower VRAM than `resident`; use this when H100-class memory is tight. |
-| 2 GPUs | `--num-gpus 2 --enable-cfg-parallel --ltx2-two-stage-device-mode resident` | Fastest common 2-GPU setup. |
-| 4 GPUs | `--num-gpus 4 --tp-size 2 --enable-cfg-parallel --ltx2-two-stage-device-mode resident` | Fastest common 4-GPU layout: TP2 inside each CFG branch. |
-| Official comparison | `--ltx2-two-stage-device-mode original` | Use this only when matching the original stage-switch semantics matters. |
+| LTX-2.3, 1 high-VRAM GPU | `--ltx2-two-stage-device-mode resident` | Fastest two-stage setup when both DiTs fit. |
+| LTX-2.3, 1 standard GPU | `--ltx2-two-stage-device-mode snapshot` | Lower VRAM than `resident`; use this when H100-class memory is tight. |
+| LTX-2, 2 GPUs | `--num-gpus 2 --enable-cfg-parallel` | Fastest verified 2-GPU setup; keep `--dit-layerwise-offload` disabled unless memory is tight. |
+| LTX-2.3, 2 GPUs | `--num-gpus 2 --enable-cfg-parallel --ltx2-two-stage-device-mode resident` | Fastest common 2-GPU setup. |
+| LTX-2.3, 4 GPUs | `--num-gpus 4 --tp-size 2 --enable-cfg-parallel --ltx2-two-stage-device-mode resident` | Fastest common 4-GPU layout: TP2 inside each CFG branch. |
+| Official comparison | `--ltx2-two-stage-device-mode original` | Use this only when matching the original LTX-2.3 stage-switch semantics matters. |
Use `--enable-cfg-parallel` for degree-2 CFG parallel. Use `--cfg-parallel-size` only when you explicitly need a different CFG branch count. If `resident` exceeds available VRAM, keep the same parallelism preset and switch only the device mode to `snapshot`.
diff --git a/docs_new/src/snippets/diffusion/ltx-deployment.jsx b/docs_new/src/snippets/diffusion/ltx-deployment.jsx
index e4d7ca77a..2f15a7e3c 100644
--- a/docs_new/src/snippets/diffusion/ltx-deployment.jsx
+++ b/docs_new/src/snippets/diffusion/ltx-deployment.jsx
@@ -141,7 +141,7 @@ export const LTXDeployment = () => {
let command = `sglang serve \\\n --model-path ${config.repoId} \\\n --pipeline-class-name ${pipelineClass}`;
command += getParallelFlags();
- if (values.pipeline !== 'one-stage') {
+ if (values.model === 'ltx23' && values.pipeline !== 'one-stage') {
command += ` \\\n --ltx2-two-stage-device-mode ${getDeviceMode()}`;
}
diff --git a/python/sglang/multimodal_gen/runtime/layers/attention/backends/sdpa.py b/python/sglang/multimodal_gen/runtime/layers/attention/backends/sdpa.py
index 5523f6559..9345785ed 100644
--- a/python/sglang/multimodal_gen/runtime/layers/attention/backends/sdpa.py
+++ b/python/sglang/multimodal_gen/runtime/layers/attention/backends/sdpa.py
@@ -2,7 +2,10 @@
# SPDX-License-Identifier: Apache-2.0
+from contextlib import nullcontext
+
import torch
+from torch.nn.attention import SDPBackend, sdpa_kernel
from sglang.multimodal_gen.runtime.layers.attention.backends.attention_backend import ( # FlashAttentionMetadata,
AttentionBackend,
@@ -14,6 +17,13 @@ from sglang.multimodal_gen.runtime.utils.logging_utils import init_logger
logger = init_logger(__name__)
+_PYTORCH_DEFAULT_CUDA_SDP_BACKENDS = [
+ SDPBackend.CUDNN_ATTENTION,
+ SDPBackend.FLASH_ATTENTION,
+ SDPBackend.EFFICIENT_ATTENTION,
+ SDPBackend.MATH,
+]
+
class SDPABackend(AttentionBackend):
@@ -51,6 +61,7 @@ class SDPAImpl(AttentionImpl):
self.causal = causal
self.softmax_scale = softmax_scale
self.dropout = extra_impl_args.get("dropout_p", 0.0)
+ self.allow_cudnn_sdp = bool(extra_impl_args.get("allow_cudnn_sdp", False))
def forward(
self,
@@ -71,8 +82,14 @@ class SDPAImpl(AttentionImpl):
}
if query.shape[1] != key.shape[1]:
attn_kwargs["enable_gqa"] = True
- output = torch.nn.functional.scaled_dot_product_attention(
- query, key, value, **attn_kwargs
+ sdpa_context = (
+ sdpa_kernel(_PYTORCH_DEFAULT_CUDA_SDP_BACKENDS)
+ if self.allow_cudnn_sdp and query.device.type == "cuda"
+ else nullcontext()
)
+ with sdpa_context:
+ output = torch.nn.functional.scaled_dot_product_attention(
+ query, key, value, **attn_kwargs
+ )
output = output.transpose(1, 2)
return output
diff --git a/python/sglang/multimodal_gen/runtime/layers/attention/layer.py b/python/sglang/multimodal_gen/runtime/layers/attention/layer.py
index ee0127c22..71aa1c4f1 100644
--- a/python/sglang/multimodal_gen/runtime/layers/attention/layer.py
+++ b/python/sglang/multimodal_gen/runtime/layers/attention/layer.py
@@ -1,10 +1,12 @@
# Copied and adapted from: https://github.com/hao-ai-lab/FastVideo
# SPDX-License-Identifier: Apache-2.0
+from contextlib import nullcontext
from typing import Type
import torch
import torch.nn as nn
+from torch.nn.attention import SDPBackend, sdpa_kernel
from sglang.multimodal_gen.runtime.distributed.communication_op import (
sequence_model_parallel_all_gather,
@@ -35,6 +37,13 @@ from sglang.multimodal_gen.runtime.managers.forward_context import (
from sglang.multimodal_gen.runtime.platforms import AttentionBackendEnum
from sglang.multimodal_gen.utils import get_compute_dtype
+_PYTORCH_DEFAULT_CUDA_SDP_BACKENDS = [
+ SDPBackend.CUDNN_ATTENTION,
+ SDPBackend.FLASH_ATTENTION,
+ SDPBackend.EFFICIENT_ATTENTION,
+ SDPBackend.MATH,
+]
+
class UlyssesAttention(nn.Module):
"""Ulysses-style SequenceParallelism attention layer."""
@@ -246,6 +255,7 @@ class LocalAttention(nn.Module):
head_size, dtype, supported_attention_backends=supported_attention_backends
)
impl_cls = attn_backend.get_impl_cls()
+ self.allow_cudnn_sdp = bool(extra_impl_args.get("allow_cudnn_sdp", False))
self.attn_impl = impl_cls(
num_heads=num_heads,
head_size=head_size,
@@ -304,15 +314,21 @@ class LocalAttention(nn.Module):
mask = mask[:, None, :, :]
mask = (mask - 1.0) * torch.finfo(q_.dtype).max
- return torch.nn.functional.scaled_dot_product_attention(
- q_,
- k_,
- v_,
- attn_mask=mask,
- dropout_p=0.0,
- is_causal=False,
- scale=self.softmax_scale,
- ).transpose(1, 2)
+ sdpa_context = (
+ sdpa_kernel(_PYTORCH_DEFAULT_CUDA_SDP_BACKENDS)
+ if self.allow_cudnn_sdp and q_.device.type == "cuda"
+ else nullcontext()
+ )
+ with sdpa_context:
+ return torch.nn.functional.scaled_dot_product_attention(
+ q_,
+ k_,
+ v_,
+ attn_mask=mask,
+ dropout_p=0.0,
+ is_causal=False,
+ scale=self.softmax_scale,
+ ).transpose(1, 2)
output = self.attn_impl.forward(q, k, v, attn_metadata=ctx_attn_metadata)
return output
@@ -373,6 +389,7 @@ class USPAttention(nn.Module):
f"Please ensure your platform supports these backends."
)
impl_cls: Type["AttentionImpl"] = attn_backend.get_impl_cls()
+ self.allow_cudnn_sdp = bool(extra_impl_args.get("allow_cudnn_sdp", False))
self.attn_impl = impl_cls(
num_heads=num_heads,
head_size=head_size,
@@ -453,15 +470,21 @@ class USPAttention(nn.Module):
k_ = k.transpose(1, 2)
v_ = v.transpose(1, 2)
mask = _prepare_sdpa_mask(attn_mask, dtype=q_.dtype, device=q_.device)
- return torch.nn.functional.scaled_dot_product_attention(
- q_,
- k_,
- v_,
- attn_mask=mask,
- dropout_p=0.0,
- is_causal=False,
- scale=self.softmax_scale,
- ).transpose(1, 2)
+ sdpa_context = (
+ sdpa_kernel(_PYTORCH_DEFAULT_CUDA_SDP_BACKENDS)
+ if self.allow_cudnn_sdp and q_.device.type == "cuda"
+ else nullcontext()
+ )
+ with sdpa_context:
+ return torch.nn.functional.scaled_dot_product_attention(
+ q_,
+ k_,
+ v_,
+ attn_mask=mask,
+ dropout_p=0.0,
+ is_causal=False,
+ scale=self.softmax_scale,
+ ).transpose(1, 2)
if get_ring_parallel_world_size() > 1:
raise NotImplementedError(
@@ -489,15 +512,21 @@ class USPAttention(nn.Module):
k_ = k.transpose(1, 2)
v_ = v.transpose(1, 2)
mask = _prepare_sdpa_mask(gathered_mask, dtype=q_.dtype, device=q_.device)
- out = torch.nn.functional.scaled_dot_product_attention(
- q_,
- k_,
- v_,
- attn_mask=mask,
- dropout_p=0.0,
- is_causal=False,
- scale=self.softmax_scale,
- ).transpose(1, 2)
+ sdpa_context = (
+ sdpa_kernel(_PYTORCH_DEFAULT_CUDA_SDP_BACKENDS)
+ if self.allow_cudnn_sdp and q_.device.type == "cuda"
+ else nullcontext()
+ )
+ with sdpa_context:
+ out = torch.nn.functional.scaled_dot_product_attention(
+ q_,
+ k_,
+ v_,
+ attn_mask=mask,
+ dropout_p=0.0,
+ is_causal=False,
+ scale=self.softmax_scale,
+ ).transpose(1, 2)
if sp_size > 1:
out = _usp_output_all_to_all(out, head_dim=2)
return out
diff --git a/python/sglang/multimodal_gen/runtime/models/dits/ltx_2.py b/python/sglang/multimodal_gen/runtime/models/dits/ltx_2.py
index 96f513a92..178f362ab 100644
--- a/python/sglang/multimodal_gen/runtime/models/dits/ltx_2.py
+++ b/python/sglang/multimodal_gen/runtime/models/dits/ltx_2.py
@@ -4,11 +4,8 @@
from __future__ import annotations
-import functools
-import math
from typing import Any, Optional, Tuple, Union
-import numpy as np
import torch
import torch.nn as nn
import torch.nn.functional as F
@@ -98,17 +95,6 @@ def _ltx2_build_batched_perturbation_states(
return states
-@functools.lru_cache(maxsize=5)
-def _ltx2_rope_freq_grid_np(theta: float, num_pos_dims: int, dim: int) -> torch.Tensor:
- # Official LTX uses NumPy float64 for double-precision RoPE frequencies.
- n_elem = 2 * num_pos_dims
- pow_indices = np.power(
- theta,
- np.linspace(0.0, 1.0, dim // n_elem, dtype=np.float64),
- )
- return torch.tensor(pow_indices * math.pi / 2.0, dtype=torch.float32)
-
-
def apply_interleaved_rotary_emb(
x: torch.Tensor, freqs: Tuple[torch.Tensor, torch.Tensor]
) -> torch.Tensor:
@@ -351,22 +337,20 @@ class LTX2AudioVideoRotaryPosEmbed(nn.Module):
).to(device)
num_rope_elems = num_pos_dims * 2
- if self.double_precision:
- freqs = _ltx2_rope_freq_grid_np(self.theta, num_pos_dims, self.dim).to(
- device=device
- )
- else:
- pow_indices = torch.pow(
- self.theta,
- torch.linspace(
- start=0.0,
- end=1.0,
- steps=self.dim // num_rope_elems,
- dtype=torch.float32,
- device=device,
- ),
- )
- freqs = (pow_indices * torch.pi / 2.0).to(dtype=torch.float32)
+ # LTX-2.3 HQ is sensitive to RoPE rounding; keep frequency generation on
+ # the target device instead of caching a CPU/NumPy tensor.
+ freqs_dtype = torch.float64 if self.double_precision else torch.float32
+ pow_indices = torch.pow(
+ self.theta,
+ torch.linspace(
+ start=0.0,
+ end=1.0,
+ steps=self.dim // num_rope_elems,
+ dtype=freqs_dtype,
+ device=device,
+ ),
+ )
+ freqs = (pow_indices * torch.pi / 2.0).to(dtype=torch.float32)
freqs = (grid.unsqueeze(-1) * 2 - 1) * freqs
freqs = freqs.transpose(-1, -2).flatten(2)
@@ -647,6 +631,8 @@ class LTX2Attention(nn.Module):
causal=False,
supported_attention_backends=supported_attention_backends,
prefix=f"{prefix}.attn",
+ # official LTX2 torch_sdpa uses cuDNN; cuda setup disables it
+ allow_cudnn_sdp=True,
)
else:
self.attn = USPAttention(
@@ -658,6 +644,8 @@ class LTX2Attention(nn.Module):
causal=False,
supported_attention_backends=supported_attention_backends,
prefix=f"{prefix}.attn",
+ # official LTX2 torch_sdpa uses cuDNN; cuda setup disables it
+ allow_cudnn_sdp=True,
)
def forward(
@@ -1422,8 +1410,17 @@ class LTX2VideoTransformer3DModel(CachableDiT, OffloadableDiTMixin):
if hasattr(arch.rope_type, "value")
else str(arch.rope_type)
)
- rope_double_precision = bool(
- hf_config.get("rope_double_precision", arch.double_precision_rope)
+ frequencies_precision = hf_config.get("frequencies_precision")
+ if frequencies_precision is None:
+ frequencies_precision = getattr(arch, "frequencies_precision", None)
+
+ # diffusers/LTX configs use `frequencies_precision` for this RoPE switch
+ rope_double_precision = (
+ str(frequencies_precision) == "float64"
+ if frequencies_precision is not None
+ else bool(
+ hf_config.get("rope_double_precision", arch.double_precision_rope)
+ )
)
self.quantize_video_rope_coords_to_hidden_dtype = bool(
hf_config.get("quantize_video_rope_coords_to_hidden_dtype", False)
diff --git a/python/sglang/multimodal_gen/runtime/models/encoders/gemma_3.py b/python/sglang/multimodal_gen/runtime/models/encoders/gemma_3.py
index c5e6ae354..16ed42134 100644
--- a/python/sglang/multimodal_gen/runtime/models/encoders/gemma_3.py
+++ b/python/sglang/multimodal_gen/runtime/models/encoders/gemma_3.py
@@ -146,14 +146,21 @@ class Gemma3Attention(nn.Module):
prefix=f"{prefix}.o_proj",
)
- self.layer_type = (
- config.text_config.layer_types[layer_id]
- if hasattr(config.text_config, "layer_types")
- else None
- )
- self.is_sliding = (
- config.text_config.layer_types[layer_id] == "sliding_attention"
- )
+ layer_types = getattr(config.text_config, "layer_types", None)
+ if layer_types:
+ self.layer_type = layer_types[layer_id]
+ self.is_sliding = self.layer_type == "sliding_attention"
+ else:
+ # official Gemma3 uses sliding_window_pattern when layer_types is absent
+ sliding_window_pattern = getattr(
+ config.text_config, "sliding_window_pattern", None
+ )
+ self.is_sliding = (
+ bool((layer_id + 1) % sliding_window_pattern)
+ if sliding_window_pattern
+ else False
+ )
+ self.layer_type = "sliding_attention" if self.is_sliding else None
rope_parameters = getattr(config.text_config, "rope_parameters", None) or {}
layer_rope_params = {}
@@ -204,7 +211,7 @@ class Gemma3Attention(nn.Module):
self.sliding_window = None
self.window_size = (-1, -1)
- self.rotary_emb = get_rope(
+ self.rotary_pos_emb = get_rope(
self.head_dim,
rotary_dim=self.head_dim,
max_position=config.text_config.max_position_embeddings,
@@ -213,12 +220,6 @@ class Gemma3Attention(nn.Module):
is_neox_style=True,
)
- self.rope_scaling_factor = (
- float(rope_scaling["factor"])
- if rope_scaling and rope_scaling.get("factor")
- else None
- )
-
# Local Attention not support attention mask, we use global attention instead.
# self.attn = LocalAttention(
# self.num_heads,
@@ -238,26 +239,19 @@ class Gemma3Attention(nn.Module):
dim=self.head_dim, eps=config.text_config.rms_norm_eps
)
- def rotary_emb(self, positions, q, k):
- """Apply RoPE using the same device-side inv_freq materialization as LTX."""
- positions_flat = positions.flatten().float()
+ def _apply_rotary_pos_emb(self, positions, q, k):
+ positions_flat = positions.flatten().to(
+ device=self.rotary_pos_emb.cos_sin_cache.device, dtype=torch.long
+ )
+ cos_sin = self.rotary_pos_emb.cos_sin_cache.index_select(0, positions_flat)
+ cos, sin = cos_sin.chunk(2, dim=-1)
+ # match HF Gemma3: expand half-dim freqs to full head dim before rotate_half
+ cos = torch.cat((cos, cos), dim=-1).to(device=q.device, dtype=q.dtype)
+ sin = torch.cat((sin, sin), dim=-1).to(device=q.device, dtype=q.dtype)
+ cos = cos.unsqueeze(1)
+ sin = sin.unsqueeze(1)
num_tokens = positions_flat.shape[0]
- with torch.autocast(device_type=q.device.type, enabled=False):
- freq_indices = (
- torch.arange(
- 0, self.head_dim, 2, dtype=torch.int64, device=q.device
- ).float()
- / self.head_dim
- )
- inv_freq = 1.0 / (self.rope_theta**freq_indices)
- if self.rope_scaling_factor is not None:
- inv_freq = inv_freq / self.rope_scaling_factor
- freqs = torch.outer(positions_flat, inv_freq)
- emb = freqs.repeat(1, 2)
- cos = emb.cos().to(q.dtype).unsqueeze(1)
- sin = emb.sin().to(q.dtype).unsqueeze(1)
-
q = q.reshape(num_tokens, -1, self.head_dim)
k = k.reshape(num_tokens, -1, self.head_dim)
q = q * cos + _rotate_half(q) * sin
@@ -283,7 +277,7 @@ class Gemma3Attention(nn.Module):
k = self.k_norm(k)
# Apply RoPE
- q, k = self.rotary_emb(positions, q, k)
+ q, k = self._apply_rotary_pos_emb(positions, q, k)
q = q.reshape(batch_size, seq_len, self.num_heads, self.head_dim)
k = k.reshape(batch_size, seq_len, self.num_kv_heads, self.head_dim)
@@ -306,7 +300,7 @@ class Gemma3Attention(nn.Module):
attn_mask = attn_mask.masked_fill(causal, False)
if self.is_sliding and self.sliding_window is not None:
idx = torch.arange(seq_len, device=hidden_states.device)
- dist = idx[None, :] - idx[:, None]
+ dist = idx[:, None] - idx[None, :]
too_far = dist > self.sliding_window
attn_mask = attn_mask.masked_fill(too_far, False)
diff --git a/python/sglang/multimodal_gen/runtime/pipelines/ltx_2_pipeline.py b/python/sglang/multimodal_gen/runtime/pipelines/ltx_2_pipeline.py
index 3259ab363..39e2872b4 100644
--- a/python/sglang/multimodal_gen/runtime/pipelines/ltx_2_pipeline.py
+++ b/python/sglang/multimodal_gen/runtime/pipelines/ltx_2_pipeline.py
@@ -193,7 +193,6 @@ class LTX2SigmaPreparationStage(PipelineStage):
int(batch.num_inference_steps),
number_of_tokens=latent_num_frames * latent_height * latent_width,
)
- batch.sigmas.append(0.0011)
else:
batch.sigmas = build_official_ltx2_sigmas(
int(batch.num_inference_steps)
diff --git a/python/sglang/multimodal_gen/runtime/pipelines_core/executors/parallel_executor.py b/python/sglang/multimodal_gen/runtime/pipelines_core/executors/parallel_executor.py
index 3a4cf3419..07f765cbb 100644
--- a/python/sglang/multimodal_gen/runtime/pipelines_core/executors/parallel_executor.py
+++ b/python/sglang/multimodal_gen/runtime/pipelines_core/executors/parallel_executor.py
@@ -82,8 +82,12 @@ class ParallelExecutor(PipelineExecutor):
elif paradigm == StageParallelismType.CFG_PARALLEL:
obj_list = [batch] if rank == 0 else []
+ # `dist.broadcast(src=...)` expects a global rank for process groups.
broadcasted_list = broadcast_pyobj(
- obj_list, rank=rank, dist_group=cfg_group.cpu_group, src=0
+ obj_list,
+ rank=get_world_rank(),
+ dist_group=cfg_group.cpu_group,
+ src=cfg_group.ranks[0],
)
if rank != 0:
batch = broadcasted_list[0]
diff --git a/python/sglang/multimodal_gen/runtime/pipelines_core/stages/denoising_av.py b/python/sglang/multimodal_gen/runtime/pipelines_core/stages/denoising_av.py
index 6fb7a0280..aeac9cd73 100644
--- a/python/sglang/multimodal_gen/runtime/pipelines_core/stages/denoising_av.py
+++ b/python/sglang/multimodal_gen/runtime/pipelines_core/stages/denoising_av.py
@@ -354,12 +354,11 @@ class LTX2RefinementStage(LTX2AVDenoisingStage):
scheduler = clone_scheduler_runtime(original_batch_scheduler or self.scheduler)
distilled_device = scheduler.sigmas.device
+ num_steps = len(self.distilled_sigmas) - 1
# Inject `0.0011` before the terminal `0.0` to avoid the
# `sigma_next==0` singularity in res2s' `(sample - denoised) /
- # (sigma - sigma_next)`. Official `res2s_denoising_loop` does this
- # exact injection (samplers.py:262); official `euler_denoising_loop`
- # does NOT — it uses `sigma_next` directly. So gate on the active
- # sampler, not on the model variant.
+ # (sigma - sigma_next)`. This changes the final sigma pair only; it
+ # must not add an extra denoising timestep.
if self.sampler_name == "res2s" and self.distilled_sigmas[-1].item() == 0.0:
scheduler_sigmas = torch.cat(
[
@@ -372,9 +371,10 @@ class LTX2RefinementStage(LTX2AVDenoisingStage):
scheduler_sigmas = self.distilled_sigmas
scheduler.sigmas = scheduler_sigmas
- num_steps = len(scheduler_sigmas) - 1
scheduler.num_inference_steps = num_steps
- scheduler.timesteps = (scheduler_sigmas[:num_steps] * 1000).to(distilled_device)
+ scheduler.timesteps = (self.distilled_sigmas[:num_steps] * 1000).to(
+ distilled_device
+ )
scheduler._step_index = None
scheduler._begin_index = None
diff --git a/python/sglang/multimodal_gen/runtime/pipelines_core/stages/ltx_2_denoising.py b/python/sglang/multimodal_gen/runtime/pipelines_core/stages/ltx_2_denoising.py
index e21620f51..577b86aa2 100644
--- a/python/sglang/multimodal_gen/runtime/pipelines_core/stages/ltx_2_denoising.py
+++ b/python/sglang/multimodal_gen/runtime/pipelines_core/stages/ltx_2_denoising.py
@@ -422,45 +422,76 @@ class LTX2DenoisingStage(DenoisingStage):
return pred * factor
@classmethod
- def _ltx2_combine_guided_x0_parallel(
+ def _ltx2_combine_guided_x0_parallel_av(
cls,
*,
- latents: torch.Tensor,
- local_velocities: dict[str, torch.Tensor],
- sigma: float | torch.Tensor,
- cfg_scale: float,
- stg_scale: float,
- rescale_scale: float,
- modality_scale: float,
- ) -> torch.Tensor:
- """Combine stage-1 guidance passes that were split across CFG ranks.
+ video_latents: torch.Tensor,
+ audio_latents: torch.Tensor,
+ local_video_velocities: dict[str, torch.Tensor],
+ local_audio_velocities: dict[str, torch.Tensor],
+ video_sigma: float | torch.Tensor,
+ audio_sigma: float | torch.Tensor,
+ video_cfg_scale: float,
+ video_stg_scale: float,
+ video_rescale_scale: float,
+ video_modality_scale: float,
+ audio_cfg_scale: float,
+ audio_stg_scale: float,
+ audio_rescale_scale: float,
+ audio_modality_scale: float,
+ ) -> tuple[torch.Tensor, torch.Tensor]:
+ """Reconstruct CFG branches once for both modalities before guider math."""
+ first_video_velocity = next(iter(local_video_velocities.values()))
+ first_audio_velocity = next(iter(local_audio_velocities.values()))
+ video_template = cls._ltx2_velocity_to_x0(
+ video_latents, first_video_velocity, video_sigma
+ )
+ audio_template = cls._ltx2_velocity_to_x0(
+ audio_latents, first_audio_velocity, audio_sigma
+ )
+ video_numel = video_template.numel()
+ branches: dict[str, tuple[torch.Tensor, torch.Tensor]] = {}
- Each pass is one model forward with a different conditioning setup:
- positive prompt, negative prompt, attention-disabled perturbation, or
- audio/video cross-attention disabled. A rank only owns some passes, so
- it contributes weighted x0 terms for those passes and all-reduce
- reconstructs the full guided x0 on every rank.
- """
- coefficients = {
- "cond": cfg_scale + stg_scale + modality_scale - 1.0,
- "neg": 1.0 - cfg_scale,
- "perturbed": -stg_scale,
- "modality": 1.0 - modality_scale,
- }
- first_velocity = next(iter(local_velocities.values()))
- template = cls._ltx2_velocity_to_x0(latents, first_velocity, sigma)
- cond_partial = torch.zeros_like(template)
- pred_partial = torch.zeros_like(template)
+ for name in ("cond", "neg", "perturbed", "modality"):
+ if name in local_video_velocities:
+ local_video = cls._ltx2_velocity_to_x0(
+ video_latents, local_video_velocities[name], video_sigma
+ )
+ local_audio = cls._ltx2_velocity_to_x0(
+ audio_latents, local_audio_velocities[name], audio_sigma
+ )
+ else:
+ local_video = torch.zeros_like(video_template)
+ local_audio = torch.zeros_like(audio_template)
+ flat = torch.cat((local_video.reshape(-1), local_audio.reshape(-1)))
+ flat = cfg_model_parallel_all_reduce(flat)
+ branches[name] = (
+ flat[:video_numel].reshape_as(video_template),
+ flat[video_numel:].reshape_as(audio_template),
+ )
- for name, velocity in local_velocities.items():
- denoised = cls._ltx2_velocity_to_x0(latents, velocity, sigma)
- if name == "cond":
- cond_partial = cond_partial + denoised
- pred_partial = pred_partial + denoised * coefficients[name]
-
- cond = cfg_model_parallel_all_reduce(cond_partial)
- pred = cfg_model_parallel_all_reduce(pred_partial)
- return cls._ltx2_apply_rescale(cond, pred, rescale_scale)
+ # folding the coefficients changes bf16 rounding and drifts from single-GPU
+ guided_video = cls._ltx2_calculate_guided_x0(
+ cond=branches["cond"][0],
+ uncond_text=branches["neg"][0],
+ uncond_perturbed=branches["perturbed"][0],
+ uncond_modality=branches["modality"][0],
+ cfg_scale=video_cfg_scale,
+ stg_scale=video_stg_scale,
+ rescale_scale=video_rescale_scale,
+ modality_scale=video_modality_scale,
+ )
+ guided_audio = cls._ltx2_calculate_guided_x0(
+ cond=branches["cond"][1],
+ uncond_text=branches["neg"][1],
+ uncond_perturbed=branches["perturbed"][1],
+ uncond_modality=branches["modality"][1],
+ cfg_scale=audio_cfg_scale,
+ stg_scale=audio_stg_scale,
+ rescale_scale=audio_rescale_scale,
+ modality_scale=audio_modality_scale,
+ )
+ return guided_video, guided_audio
@staticmethod
def _ltx2_channelwise_normalize(noise: torch.Tensor) -> torch.Tensor:
@@ -556,7 +587,9 @@ class LTX2DenoisingStage(DenoisingStage):
dtype=sliced.dtype,
)
sliced = torch.cat([sliced, pad], dim=1)
- return sliced.to(dtype=reference_tensor.dtype)
+ return sliced
+ # The native HQ SDE path consumes this through `.float()`; keep the
+ # original downcast boundary before that upcast to preserve the trajectory.
return cls._ltx2_res2s_new_noise(reference_tensor, generator).to(
dtype=reference_tensor.dtype
)
@@ -703,6 +736,8 @@ class LTX2DenoisingStage(DenoisingStage):
update (midpoint SDE, bongmath anchor refinement, midpoint re-eval,
final RK2 combination with SDE noise). Mirrors the guided stage-1 res2s
math but without CFG/STG (stage-2 HQ uses the simple CFG path).
+ Raw HQ model timesteps are only inputs to the DiT call; stage-2 res2s
+ math stays in scheduler sigma space.
"""
sigma_val = float(sigma.item())
sigma_next_val = float(sigma_next.item())
@@ -711,24 +746,10 @@ class LTX2DenoisingStage(DenoisingStage):
denoised_video = ctx.latents.float()
denoised_audio = ctx.audio_latents.float()
else:
- video_sigma_for_x0 = (
- model_video_timestep
- if ctx.use_ltx23_hq_timestep_semantics
- and model_video_timestep is not None
- else sigma
+ denoised_video = ctx.latents.float() - sigma * model_video_velocity.float()
+ denoised_audio = (
+ ctx.audio_latents.float() - sigma * model_audio_velocity.float()
)
- audio_sigma_for_x0 = (
- model_audio_timestep
- if ctx.use_ltx23_hq_timestep_semantics
- and model_audio_timestep is not None
- else sigma
- )
- denoised_video = self._ltx2_velocity_to_x0(
- ctx.latents, model_video_velocity, video_sigma_for_x0
- ).float()
- denoised_audio = self._ltx2_velocity_to_x0(
- ctx.audio_latents, model_audio_velocity, audio_sigma_for_x0
- ).float()
if sigma_val == 0.0 or sigma_next_val == 0.0:
next_video = denoised_video.to(dtype=ctx.latents.dtype)
@@ -738,14 +759,9 @@ class LTX2DenoisingStage(DenoisingStage):
sigma_d = sigma.double()
sigma_next_d = sigma_next.double()
- if ctx.use_ltx23_hq_timestep_semantics:
- h = self._ltx2_res2s_step_size_scalar(sigma_d, sigma_next_d)
- a21, b1, b2 = self._ltx2_get_res2s_coefficients_scalar(h)
- h_value = h
- else:
- h = -torch.log(torch.clamp(sigma_next_d / sigma_d, min=1e-12))
- a21, b1, b2 = self._ltx2_get_res2s_coefficients(h)
- h_value = float(h.item())
+ h = -torch.log(torch.clamp(sigma_next_d / sigma_d, min=1e-12))
+ a21, b1, b2 = self._ltx2_get_res2s_coefficients(h)
+ h_value = float(h.item())
sub_sigma = torch.sqrt(torch.clamp(sigma_d * sigma_next_d, min=0.0))
anchor_video = ctx.latents.double()
@@ -809,22 +825,8 @@ class LTX2DenoisingStage(DenoisingStage):
midpoint_video_model_latents, midpoint_audio_model_latents, sub_sigma
)
- mid_video_sigma_for_x0 = (
- mid_video_timestep
- if ctx.use_ltx23_hq_timestep_semantics and mid_video_timestep is not None
- else sub_sigma
- )
- mid_audio_sigma_for_x0 = (
- mid_audio_timestep
- if ctx.use_ltx23_hq_timestep_semantics and mid_audio_timestep is not None
- else sub_sigma
- )
- midpoint_denoised_video = self._ltx2_velocity_to_x0(
- midpoint_video_latents, mid_v, mid_video_sigma_for_x0
- ).float()
- midpoint_denoised_audio = self._ltx2_velocity_to_x0(
- midpoint_audio_latents, mid_a, mid_audio_sigma_for_x0
- ).float()
+ midpoint_denoised_video = midpoint_video_latents.float() - sub_sigma * mid_v
+ midpoint_denoised_audio = midpoint_audio_latents.float() - sub_sigma * mid_a
eps2_video = midpoint_denoised_video.double() - anchor_video
eps2_audio = midpoint_denoised_audio.double() - anchor_audio
@@ -848,23 +850,19 @@ class LTX2DenoisingStage(DenoisingStage):
ctx.audio_latents, batch
).float()
)
- sde_sigma = sigma if ctx.use_ltx23_hq_timestep_semantics else sigma_d
- sde_sigma_next = (
- sigma_next if ctx.use_ltx23_hq_timestep_semantics else sigma_next_d
- )
next_video = self._ltx2_res2s_sde_step(
sample=anchor_video,
denoised_sample=next_video_det,
- sigma=sde_sigma,
- sigma_next=sde_sigma_next,
+ sigma=sigma_d,
+ sigma_next=sigma_next_d,
noise=step_noise_video,
terminal=False,
)
next_audio = self._ltx2_res2s_sde_step(
sample=anchor_audio,
denoised_sample=next_audio_det,
- sigma=sde_sigma,
- sigma_next=sde_sigma_next,
+ sigma=sigma_d,
+ sigma_next=sigma_next_d,
noise=step_noise_audio,
terminal=False,
)
@@ -1574,9 +1572,19 @@ class LTX2DenoisingStage(DenoisingStage):
ctx.denoise_mask = ctx.denoise_mask.to(device)
if ctx.clean_latent is not None:
ctx.clean_latent = ctx.clean_latent.to(device)
+ self._move_ltx2_scheduler_tensors_to_device(ctx.scheduler, device)
+ self._move_ltx2_scheduler_tensors_to_device(ctx.audio_scheduler, device)
return ctx
+ @staticmethod
+ def _move_ltx2_scheduler_tensors_to_device(scheduler: object, device) -> None:
+ # cfg-parallel batches are broadcast from rank 0; scheduler state must be local
+ for name in ("sigmas", "timesteps"):
+ value = getattr(scheduler, name, None)
+ if isinstance(value, torch.Tensor):
+ setattr(scheduler, name, value.to(device))
+
def _before_denoising_loop(
self, ctx: LTX2DenoisingContext, batch: Req, server_args: ServerArgs
) -> None:
@@ -1652,9 +1660,13 @@ class LTX2DenoisingStage(DenoisingStage):
)
use_official_cfg_path = stage1_guider_params is None
if use_official_cfg_path:
- cfg_parallel = (
- server_args.enable_cfg_parallel and batch.do_classifier_free_guidance
- )
+ do_two_branch_cfg = batch.do_classifier_free_guidance
+ if ctx.stage == "stage2" and is_ltx2_two_stage_pipeline_name(
+ server_args.pipeline_class_name
+ ):
+ # official two-stage stage 2 is a distilled positive-only denoiser
+ do_two_branch_cfg = False
+ cfg_parallel = server_args.enable_cfg_parallel and do_two_branch_cfg
cfg_rank = get_classifier_free_guidance_rank() if cfg_parallel else 0
if cfg_parallel:
@@ -1691,7 +1703,7 @@ class LTX2DenoisingStage(DenoisingStage):
audio_encoder_hidden_states=batch.audio_prompt_embeds[0],
encoder_attention_mask=prompt_attention_mask,
)
- if batch.do_classifier_free_guidance:
+ if do_two_branch_cfg:
cfg_batch_size = batch_size * 2
model_kwargs = self._repeat_ltx2_model_kwargs_batch(
model_kwargs, cfg_batch_size
@@ -1735,7 +1747,7 @@ class LTX2DenoisingStage(DenoisingStage):
model_video, model_audio = self._combine_cfg_parallel_av(
model_video, model_audio, float(batch.guidance_scale), cfg_rank
)
- elif batch.do_classifier_free_guidance:
+ elif do_two_branch_cfg:
model_video_uncond, model_video_text = model_video.chunk(2)
model_audio_uncond, model_audio_text = model_audio.chunk(2)
model_video = model_video_uncond + (
@@ -1780,7 +1792,7 @@ class LTX2DenoisingStage(DenoisingStage):
audio_encoder_hidden_states=batch.audio_prompt_embeds[0],
encoder_attention_mask=prompt_attention_mask,
)
- if batch.do_classifier_free_guidance:
+ if do_two_branch_cfg:
cfg_batch_size = batch_size_local * 2
model_kwargs_local = self._repeat_ltx2_model_kwargs_batch(
model_kwargs_local, cfg_batch_size
@@ -1827,7 +1839,7 @@ class LTX2DenoisingStage(DenoisingStage):
mid_v = mid_v.float()
mid_a = mid_a.float()
- if batch.do_classifier_free_guidance:
+ if do_two_branch_cfg:
mid_v_u, mid_v_t = mid_v.chunk(2)
mid_a_u, mid_a_t = mid_a.chunk(2)
mid_v = mid_v_u + batch.guidance_scale * (mid_v_t - mid_v_u)
@@ -2202,20 +2214,43 @@ class LTX2DenoisingStage(DenoisingStage):
) * ctx.denoise_mask.squeeze(-1)
if stage1_cfg_parallel:
- guided_video = self._ltx2_combine_guided_x0_parallel(
- latents=video_latents,
- local_velocities={
- name: output[0] for name, output in pass_outputs.items()
- },
- sigma=video_sigma_for_x0,
- cfg_scale=float(stage1_guider_params["video_cfg_scale"]),
- stg_scale=float(stage1_guider_params["video_stg_scale"]),
- rescale_scale=float(
- stage1_guider_params["video_rescale_scale"]
- ),
- modality_scale=float(
- stage1_guider_params["video_modality_scale"]
- ),
+ guided_video, guided_audio = (
+ self._ltx2_combine_guided_x0_parallel_av(
+ video_latents=video_latents,
+ audio_latents=audio_latents,
+ local_video_velocities={
+ name: output[0] for name, output in pass_outputs.items()
+ },
+ local_audio_velocities={
+ name: output[1] for name, output in pass_outputs.items()
+ },
+ video_sigma=video_sigma_for_x0,
+ audio_sigma=audio_sigma_for_x0,
+ video_cfg_scale=float(
+ stage1_guider_params["video_cfg_scale"]
+ ),
+ video_stg_scale=float(
+ stage1_guider_params["video_stg_scale"]
+ ),
+ video_rescale_scale=float(
+ stage1_guider_params["video_rescale_scale"]
+ ),
+ video_modality_scale=float(
+ stage1_guider_params["video_modality_scale"]
+ ),
+ audio_cfg_scale=float(
+ stage1_guider_params["audio_cfg_scale"]
+ ),
+ audio_stg_scale=float(
+ stage1_guider_params["audio_stg_scale"]
+ ),
+ audio_rescale_scale=float(
+ stage1_guider_params["audio_rescale_scale"]
+ ),
+ audio_modality_scale=float(
+ stage1_guider_params["audio_modality_scale"]
+ ),
+ )
)
if video_skip and ctx.last_denoised_video is not None:
denoised_video_local = ctx.last_denoised_video
@@ -2224,21 +2259,6 @@ class LTX2DenoisingStage(DenoisingStage):
if update_skip_cache:
ctx.last_denoised_video = guided_video
- guided_audio = self._ltx2_combine_guided_x0_parallel(
- latents=audio_latents,
- local_velocities={
- name: output[1] for name, output in pass_outputs.items()
- },
- sigma=audio_sigma_for_x0,
- cfg_scale=float(stage1_guider_params["audio_cfg_scale"]),
- stg_scale=float(stage1_guider_params["audio_stg_scale"]),
- rescale_scale=float(
- stage1_guider_params["audio_rescale_scale"]
- ),
- modality_scale=float(
- stage1_guider_params["audio_modality_scale"]
- ),
- )
if audio_skip and ctx.last_denoised_audio is not None:
denoised_audio_local = ctx.last_denoised_audio
else:
diff --git a/python/sglang/multimodal_gen/runtime/server_args.py b/python/sglang/multimodal_gen/runtime/server_args.py
index 7514e0de9..d98cfddd3 100644
--- a/python/sglang/multimodal_gen/runtime/server_args.py
+++ b/python/sglang/multimodal_gen/runtime/server_args.py
@@ -614,9 +614,15 @@ class ServerArgs(DisaggArgsMixin):
if component_name is None:
continue
key = component_name.replace("-", "_")
- backend = self.component_attention_backends.get(key)
- if backend is not None:
- return AttentionBackendEnum[backend.upper()], key
+ fallback_keys = [key]
+ if key.endswith("_2"):
+ # Secondary two-stage components inherit the base component
+ # backend unless explicitly overridden.
+ fallback_keys.append(key[:-2])
+ for backend_key in fallback_keys:
+ backend = self.component_attention_backends.get(backend_key)
+ if backend is not None:
+ return AttentionBackendEnum[backend.upper()], backend_key
return None, None
def _adjust_warmup(self):
diff --git a/python/sglang/multimodal_gen/test/server/consistency_threshold.json b/python/sglang/multimodal_gen/test/server/consistency_threshold.json
index f3e85286f..e67ae720c 100644
--- a/python/sglang/multimodal_gen/test/server/consistency_threshold.json
+++ b/python/sglang/multimodal_gen/test/server/consistency_threshold.json
@@ -110,15 +110,15 @@
"mean_abs_diff_threshold": 10.0
},
"ltx_2.3_one_stage_ti2v": {
- "clip_threshold": 0.64,
- "ssim_threshold": 0.42,
- "psnr_threshold": 8.8,
- "mean_abs_diff_threshold": 59.0
+ "clip_threshold": 0.84,
+ "ssim_threshold": 0.78,
+ "psnr_threshold": 20.5,
+ "mean_abs_diff_threshold": 11.0
},
"ltx_2.3_two_stage_t2v_2gpus": {
"clip_threshold": 0.79,
"ssim_threshold": 0.12,
- "psnr_threshold": 12.1,
+ "psnr_threshold": 16.0,
"mean_abs_diff_threshold": 51.0
},
"wan2_1_t2v_1.3b_teacache_enabled": {
@@ -254,10 +254,10 @@
"mean_abs_diff_threshold": 45.0
},
"ltx_2_3_two_stage_ti2v_2gpus": {
- "clip_threshold": 0.92,
- "ssim_threshold": 0.58,
- "psnr_threshold": 17.5,
- "mean_abs_diff_threshold": 20.0
+ "clip_threshold": 0.55,
+ "ssim_threshold": 0.29,
+ "psnr_threshold": 11.7,
+ "mean_abs_diff_threshold": 47.0
}
},
"default_clip_threshold_image": 0.92,
diff --git a/python/sglang/multimodal_gen/test/server/gpu_cases.py b/python/sglang/multimodal_gen/test/server/gpu_cases.py
index 2f5c000c3..39fb54b53 100644
--- a/python/sglang/multimodal_gen/test/server/gpu_cases.py
+++ b/python/sglang/multimodal_gen/test/server/gpu_cases.py
@@ -601,8 +601,7 @@ TWO_GPU_CASES = [
"ltx_2_two_stage_t2v",
DiffusionServerArgs(
model_path="Lightricks/LTX-2",
- ulysses_degree=2,
- dit_layerwise_offload=True,
+ cfg_parallel=True,
extras=["--pipeline-class-name LTX2TwoStagePipeline"],
),
T2V_sampling_params,
@@ -613,7 +612,7 @@ TWO_GPU_CASES = [
model_path="Lightricks/LTX-2.3",
cfg_parallel=True,
extras=[
- "--pipeline-class-name LTX2TwoStagePipeline --ltx2-two-stage-device-mode original"
+ "--pipeline-class-name LTX2TwoStagePipeline --ltx2-two-stage-device-mode original",
],
),
TI2V_sampling_params,
@@ -634,10 +633,10 @@ TWO_GPU_CASES = [
cfg_parallel=True,
extras=[
"--pipeline-class-name LTX2TwoStagePipeline",
- "--ltx2-two-stage-device-mode original",
+ "--component-attention-backends transformer=fa",
],
),
- T2V_sampling_params,
+ DiffusionSamplingParams(prompt=T2V_PROMPT, extras={"seed": 42}),
run_component_accuracy_check=False,
),
# I2V LoRA test case
@@ -708,7 +707,7 @@ TWO_GPU_CASES = [
"ltx_2.3_one_stage_ti2v",
DiffusionServerArgs(
model_path="Lightricks/LTX-2.3",
- ulysses_degree=2,
+ cfg_parallel=True,
),
TI2V_sampling_params,
run_component_accuracy_check=False,
diff --git a/python/sglang/multimodal_gen/test/server/perf_baselines.json b/python/sglang/multimodal_gen/test/server/perf_baselines.json
index 08685b75c..393a73137 100644
--- a/python/sglang/multimodal_gen/test/server/perf_baselines.json
+++ b/python/sglang/multimodal_gen/test/server/perf_baselines.json
@@ -1096,68 +1096,70 @@
},
"ltx_2_two_stage_t2v": {
"stages_ms": {
- "InputValidationStage": 0.1,
- "TextEncodingStage": 1830.33,
- "LTX2TextConnectorStage": 9.61,
- "LTX2HalveResolutionStage": 0.06,
- "LTX2LoRASwitchStage": 11578.48,
- "LTX2SigmaPreparationStage": 0.18,
- "TimestepPreparationStage": 19.37,
- "LTX2AVLatentPreparationStage": 0.23,
- "LTX2AVDenoisingStage": 53177.49,
- "LTX2UpsampleStage": 2104.17,
- "LTX2RefinementStage": 3947.13,
- "LTX2AVDecodingStage": 332.07
+ "InputValidationStage": 0.03,
+ "TextEncodingStage": 1463.27,
+ "LTX2TextConnectorStage": 12.85,
+ "LTX2HalveResolutionStage": 0.11,
+ "LTX2LoRASwitchStage": 325.46,
+ "LTX2SigmaPreparationStage": 0.25,
+ "TimestepPreparationStage": 7.85,
+ "LTX2AVLatentPreparationStage": 0.34,
+ "LTX2ImageEncodingStage": 0.02,
+ "LTX2AVDenoisingStage": 7744.44,
+ "LTX2UpsampleStage": 2.98,
+ "LTX2RefinementStage": 666.08,
+ "LTX2AVDecodingStage": 338.87,
+ "per_frame_generation": null
},
"denoise_step_ms": {
- "0": 1186.27,
- "1": 1331.86,
- "2": 1330.41,
- "3": 1331.28,
- "4": 1331.5,
- "5": 1331.45,
- "6": 1331.79,
- "7": 1331.59,
- "8": 1331.55,
- "9": 1331.55,
- "10": 1331.51,
- "11": 1331.34,
- "12": 1331.48,
- "13": 1331.38,
- "14": 1331.74,
- "15": 1331.84,
- "16": 1331.09,
- "17": 1331.79,
- "18": 1332.34,
- "19": 1337.7,
- "20": 1337.53,
- "21": 1334.48,
- "22": 1334.87,
- "23": 1333.28,
- "24": 1333.15,
- "25": 1333.82,
- "26": 1333.55,
- "27": 1339.35,
- "28": 1336.96,
- "29": 1335.25,
- "30": 1331.8,
- "31": 1339.52,
- "32": 1334.1,
- "33": 1331.96,
- "34": 1331.78,
- "35": 1332.5,
- "36": 1331.3,
- "37": 1331.75,
- "38": 1331.94,
- "39": 1331.84,
- "40": 1278.82,
- "41": 1330.68,
- "42": 1331.7
+ "0": 165.1,
+ "1": 309.19,
+ "2": 166.63,
+ "3": 175.53,
+ "4": 158.77,
+ "5": 191.1,
+ "6": 203.59,
+ "7": 202.98,
+ "8": 205.09,
+ "9": 195.92,
+ "10": 226.96,
+ "11": 203.85,
+ "12": 190.75,
+ "13": 192.07,
+ "14": 193.85,
+ "15": 191.34,
+ "16": 193.56,
+ "17": 192.05,
+ "18": 189.53,
+ "19": 191.61,
+ "20": 187.52,
+ "21": 192.57,
+ "22": 190.67,
+ "23": 189.47,
+ "24": 187.38,
+ "25": 190.22,
+ "26": 196.7,
+ "27": 185.05,
+ "28": 189.59,
+ "29": 209.85,
+ "30": 194.47,
+ "31": 189.43,
+ "32": 189.58,
+ "33": 188.41,
+ "34": 198.11,
+ "35": 188.45,
+ "36": 187.06,
+ "37": 188.65,
+ "38": 200.22,
+ "39": 156.46,
+ "40": 220.06,
+ "41": 223.51,
+ "42": 221.07
},
- "expected_e2e_ms": 73463.94,
- "expected_avg_denoise_ms": 1328.22,
- "expected_median_denoise_ms": 1331.79,
- "estimated_full_test_time_s": 133.1
+ "expected_e2e_ms": 10601.1,
+ "expected_avg_denoise_ms": 195.04,
+ "expected_median_denoise_ms": 191.34,
+ "estimated_full_test_time_s": 345.4
},
"wan2_2_ti2v_5b": {
"stages_ms": {
diff --git a/python/sglang/multimodal_gen/test/test_consistency_metrics.py b/python/sglang/multimodal_gen/test/test_consistency_metrics.py
index b77b42d3a..7cb78928b 100644
--- a/python/sglang/multimodal_gen/test/test_consistency_metrics.py
+++ b/python/sglang/multimodal_gen/test/test_consistency_metrics.py
@@ -169,3 +169,6 @@ def test_save_consistency_failure_artifact(tmp_path, monkeypatch):
assert artifact_path.suffix == ".png"
assert (tmp_path / "consistency_failures" / "summary.json").exists()
assert (tmp_path / "consistency_failures" / "index.html").exists()
+ assert (
+ tmp_path / "consistency_failures" / "generated" / "unit_image_fail_1gpu.png"
+ ).exists()
diff --git a/python/sglang/multimodal_gen/test/test_utils.py b/python/sglang/multimodal_gen/test/test_utils.py
index ccda47743..6c64ce709 100644
--- a/python/sglang/multimodal_gen/test/test_utils.py
+++ b/python/sglang/multimodal_gen/test/test_utils.py
@@ -50,12 +50,12 @@ SGL_TEST_FILES_CONSISTENCY_GT_BASES = (
SGL_TEST_FILES_OFFICIAL_CONSISTENCY_GT_BASE,
SGL_TEST_FILES_SGLANG_CONSISTENCY_GT_BASE,
)
-# Keep non-comparable LTX CI scenarios on sglang_generated rather than hiding
-# remaining semantic gaps behind very loose official thresholds.
+# LTX cases listed here compare against official-generated GT.
SGL_TEST_FILES_OFFICIAL_CONSISTENCY_GT_CASES = frozenset(
{
"ltx_2.3_one_stage_ti2v",
"ltx_2.3_two_stage_t2v_2gpus",
+ "ltx_2_3_two_stage_ti2v_2gpus",
}
)
CONSISTENCY_THRESHOLD_JSON_PATH = (
@@ -1458,6 +1458,7 @@ def _consistency_failure_record(
is_video: bool,
output_format: str | None,
image_name: str,
+ generated_files: list[str],
gt_remote_files: list[tuple[str, str]] | None,
) -> dict[str, Any]:
return {
@@ -1466,6 +1467,7 @@ def _consistency_failure_record(
"is_video": is_video,
"output_format": output_format,
"comparison_png": image_name,
+ "generated_files": generated_files,
"metrics": {
"min_clip_similarity": _json_metric_value(result.min_similarity),
"min_ssim": _json_metric_value(result.min_ssim),
@@ -1499,6 +1501,36 @@ def _consistency_failure_record(
}
+def _save_generated_artifact_images(
+ out_dir: Path,
+ case_id: str,
+ num_gpus: int,
+ output_frames: list[np.ndarray],
+ is_video: bool,
+ output_format: str | None,
+) -> list[str]:
+ generated_dir = out_dir / "generated"
+ generated_dir.mkdir(parents=True, exist_ok=True)
+
+ safe_case_id = _safe_artifact_name(case_id)
+ if is_video:
+ suffixes = ("frame_0", "frame_mid", "frame_last")
+ filenames = [
+ f"{safe_case_id}_{num_gpus}gpu_{suffix}.png"
+ for suffix in suffixes[: len(output_frames)]
+ ]
+ else:
+ ext = output_format_to_ext(output_format)
+ filenames = [f"{safe_case_id}_{num_gpus}gpu.{ext}"]
+
+ generated_files = []
+ for frame, filename in zip(output_frames, filenames):
+ path = generated_dir / filename
+ Image.fromarray(_ensure_rgb_uint8_image(frame)).save(path)
+ generated_files.append(str(path.relative_to(out_dir)))
+ return generated_files
+
+
def _write_consistency_failure_index(
out_dir: Path,
records: list[dict[str, Any]],
@@ -1508,6 +1540,15 @@ def _write_consistency_failure_index(
case_id = html.escape(record["case_id"])
png = html.escape(record["comparison_png"])
metrics = record["metrics"]
+ generated_links = "".join(
+ f'{html.escape(path)}'
+ for path in record.get("generated_files", [])
+ )
+ generated_html = (
+ f"Generated images:
"
+ if generated_links
+ else ""
+ )
sections.append(
""
f"{case_id} ({record['num_gpus']} GPU)
"
@@ -1518,6 +1559,7 @@ def _write_consistency_failure_index(
f"mean_abs_diff={metrics['max_mean_abs_diff']}"
"
"
f'
'
+ f"{generated_html}"
""
)
@@ -1529,6 +1571,7 @@ def _write_consistency_failure_index(
"section{margin:0 0 28px;padding:16px;background:white;border:1px solid #ddd;border-radius:6px}"
"h2{font-size:18px;margin:0 0 8px}"
"p{margin:0 0 12px;color:#444}"
+ "ul{margin:0 0 12px;padding-left:20px}"
"img{max-width:100%;height:auto;border:1px solid #ddd}"
""
"Diffusion consistency failures
" + "".join(sections) + "