feat: Gemma4 text generation support (CORE-30) (#13376)

* initial gemma4 support

* parity with reference implementation

outputs can 100% match transformers with same sdpa flags, checkpoint this and then optimize

* Cleanup, video fixes

* cleanup, enable fused rms norm by default

* update comment

* Cleanup

* Update sd.py

* Various fixes

* Add fp8 scaled embedding support

* small fixes

* Translate think tokens

* Fix image encoder attention mask type

So it works with basic attention

* Handle thinking tokens different only for Gemma4

* Code cleanup

* Update nodes_textgen.py

* Use embed scale class instead of buffer

Slight difference to HF, but technically more accurate and simpler code

* Default to fused rms_norm

* Update gemma4.py
This commit is contained in:
Jukka Seppänen
2026-05-03 05:46:15 +03:00
committed by GitHub
parent f756d801a1
commit be95871adc
11 changed files with 1453 additions and 42 deletions

View File

@@ -14,6 +14,8 @@ from .sub_quadratic_attention import efficient_dot_product_attention
from comfy import model_management
TORCH_HAS_GQA = model_management.torch_version_numeric >= (2, 5)
if model_management.xformers_enabled():
import xformers
import xformers.ops
@@ -150,7 +152,12 @@ def attention_basic(q, k, v, heads, mask=None, attn_precision=None, skip_reshape
b, _, dim_head = q.shape
dim_head //= heads
scale = dim_head ** -0.5
if kwargs.get("enable_gqa", False) and q.shape[-3] != k.shape[-3]:
n_rep = q.shape[-3] // k.shape[-3]
k = k.repeat_interleave(n_rep, dim=-3)
v = v.repeat_interleave(n_rep, dim=-3)
scale = kwargs.get("scale", dim_head ** -0.5)
h = heads
if skip_reshape:
@@ -219,6 +226,10 @@ def attention_sub_quad(query, key, value, heads, mask=None, attn_precision=None,
b, _, dim_head = query.shape
dim_head //= heads
if "scale" in kwargs:
# Pre-scale query to match requested scale (cancels internal 1/sqrt(dim_head))
query = query * (kwargs["scale"] * dim_head ** 0.5)
if skip_reshape:
query = query.reshape(b * heads, -1, dim_head)
value = value.reshape(b * heads, -1, dim_head)
@@ -290,7 +301,7 @@ def attention_split(q, k, v, heads, mask=None, attn_precision=None, skip_reshape
b, _, dim_head = q.shape
dim_head //= heads
scale = dim_head ** -0.5
scale = kwargs.get("scale", dim_head ** -0.5)
if skip_reshape:
q, k, v = map(
@@ -500,8 +511,13 @@ def attention_pytorch(q, k, v, heads, mask=None, attn_precision=None, skip_resha
if mask.ndim == 3:
mask = mask.unsqueeze(1)
# Pass through extra SDPA kwargs (scale, enable_gqa) if provided
# enable_gqa requires PyTorch 2.5+; older versions use manual KV expansion above
sdpa_keys = ("scale", "enable_gqa") if TORCH_HAS_GQA else ("scale",)
sdpa_extra = {k: v for k, v in kwargs.items() if k in sdpa_keys}
if SDP_BATCH_LIMIT >= b:
out = comfy.ops.scaled_dot_product_attention(q, k, v, attn_mask=mask, dropout_p=0.0, is_causal=False)
out = comfy.ops.scaled_dot_product_attention(q, k, v, attn_mask=mask, dropout_p=0.0, is_causal=False, **sdpa_extra)
if not skip_output_reshape:
out = (
out.transpose(1, 2).reshape(b, -1, heads * dim_head)
@@ -519,7 +535,7 @@ def attention_pytorch(q, k, v, heads, mask=None, attn_precision=None, skip_resha
k[i : i + SDP_BATCH_LIMIT],
v[i : i + SDP_BATCH_LIMIT],
attn_mask=m,
dropout_p=0.0, is_causal=False
dropout_p=0.0, is_causal=False, **sdpa_extra
).transpose(1, 2).reshape(-1, q.shape[2], heads * dim_head)
return out