Skip to content

[PyTorch] Fix L3 FA tests #2709

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
cyanguwa merged 3 commits into from
Feb 28, 2026
Merged

[PyTorch] Fix L3 FA tests #2709

Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
5f4207e
fix L3 FA fp8 tests
cyanguwa Feb 26, 2026
1a40989
[pre-commit.ci] auto fixes from pre-commit.com hooks
pre-commit-ci[bot] Feb 26, 2026
229b1ef
fix skip logic based on reference backend
cyanguwa Feb 27, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
154 changes: 77 additions & 77 deletions tests/pytorch/attention/test_attention.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1865,7 +1865,7 @@ def test_mha_fp8_vs_f16(
)
fp8_meta = {}
fp8_meta["recipe"] = fp8_recipe
available_backends, _, fused_attn_backends = get_available_attention_backends(
available_backends, _, _ = get_available_attention_backends(
config,
qkv_dtype=torch.float8_e4m3fn,
qkv_layout=qkv_format.replace("hd", "h3d"),
Expand All @@ -1875,20 +1875,18 @@ def test_mha_fp8_vs_f16(
deterministic=_deterministic,
)
flash_attn_supported, fused_attn_supported_fp8, unfused_attn_supported = available_backends
available_backends, _, fused_attn_backends = get_available_attention_backends(
config,
qkv_dtype=dtype,
qkv_layout=qkv_format.replace("hd", "h3d"),
is_training=is_training,
deterministic=_deterministic,
)
_, fused_attn_supported_f16, _ = available_backends
if flash_attn_supported + fused_attn_supported_fp8 < 1:
pytest.skip("No FP8 attention backend available.")
fused_attn_supported_f16 = False
if not fp8_dpa_bwd:
available_backends, _, fused_attn_backends = get_available_attention_backends(
config,
qkv_dtype=dtype,
qkv_layout=qkv_format.replace("hd", "h3d"),
is_training=is_training,
deterministic=_deterministic,
)
_, fused_attn_supported_f16, _ = available_backends
if not fused_attn_supported_f16:
pytest.skip("No attention backend available.")
if not fused_attn_supported_f16:
pytest.skip("No reference backend available.")

if flash_attn_supported:
os.environ["NVTE_FLASH_ATTN"] = "1"
Expand Down Expand Up @@ -2118,7 +2116,7 @@ def test_dpa_fp8_vs_f16(dtype, model, qkv_layout, fp8_dpa_bwd, is_training, scal
)
fp8_meta = {}
fp8_meta["recipe"] = fp8_recipe
available_backends, _, fused_attn_backends = get_available_attention_backends(
available_backends, _, _ = get_available_attention_backends(
config,
qkv_dtype=torch.float8_e4m3fn,
qkv_layout=qkv_layout,
Expand All @@ -2127,20 +2125,19 @@ def test_dpa_fp8_vs_f16(dtype, model, qkv_layout, fp8_dpa_bwd, is_training, scal
is_training=is_training,
deterministic=_deterministic,
)
flash_attn_supported, fused_attn_supported, unfused_attn_supported = available_backends
if flash_attn_supported + fused_attn_supported < 1:
flash_attn_supported, fused_attn_supported_fp8, unfused_attn_supported = available_backends
available_backends, _, _ = get_available_attention_backends(
config,
qkv_dtype=dtype,
qkv_layout=qkv_layout,
is_training=is_training,
deterministic=_deterministic,
)
_, fused_attn_supported_f16, _ = available_backends
if flash_attn_supported + fused_attn_supported_fp8 < 1:
pytest.skip("No FP8 attention backend available.")
if not fp8_dpa_bwd:
available_backends, _, fused_attn_backends = get_available_attention_backends(
config,
qkv_dtype=dtype,
qkv_layout=qkv_layout,
is_training=is_training,
deterministic=_deterministic,
)
_, fused_attn_supported, _ = available_backends
if not fused_attn_supported:
pytest.skip("No attention backend available.")
if not fused_attn_supported_f16:
pytest.skip("No reference backend available.")
if config.num_heads != config.num_gqa_groups and "3" in qkv_layout:
pytest.skip("qkv_layout not applicable for MQA/GQA")

Expand All @@ -2164,30 +2161,32 @@ def test_dpa_fp8_vs_f16(dtype, model, qkv_layout, fp8_dpa_bwd, is_training, scal
dtype, config, True, qkv_layout, is_training, fp8_recipe
)

os.environ["NVTE_FLASH_ATTN"] = "0"
os.environ["NVTE_FUSED_ATTN"] = "1"
os.environ["NVTE_UNFUSED_ATTN"] = "0"
_attention_backends["backend_selection_requires_update"] = True
logging.info("[test_dpa_fp8_vs_f16]: run with fp8_dpa = True (FusedAttention)")
fused_attn_fwd_fp8, fused_attn_bwd_fp8 = _run_dpa_fp8_vs_f16(
dtype, config, True, qkv_layout, is_training, fp8_recipe
)

os.environ["NVTE_FLASH_ATTN"] = "0"
os.environ["NVTE_FUSED_ATTN"] = "1"
os.environ["NVTE_UNFUSED_ATTN"] = "0"
if config.dropout_p == 0.0:
# test cuDNN FP8 dropout: need a FP16/BF16 reference on Blackwell
logging.info("[test_dpa_fp8_vs_f16]: run with fp8_dpa = False (FusedAttention)")
fused_attn_fwd_f16, fused_attn_bwd_f16 = _run_dpa_fp8_vs_f16(
dtype, config, False, qkv_layout, is_training, fp8_recipe
if fused_attn_supported_fp8:
os.environ["NVTE_FLASH_ATTN"] = "0"
os.environ["NVTE_FUSED_ATTN"] = "1"
os.environ["NVTE_UNFUSED_ATTN"] = "0"
_attention_backends["backend_selection_requires_update"] = True
logging.info("[test_dpa_fp8_vs_f16]: run with fp8_dpa = True (FusedAttention)")
fused_attn_fwd_fp8, fused_attn_bwd_fp8 = _run_dpa_fp8_vs_f16(
dtype, config, True, qkv_layout, is_training, fp8_recipe
)

if fused_attn_supported_f16:
os.environ["NVTE_FLASH_ATTN"] = "0"
os.environ["NVTE_FUSED_ATTN"] = "1"
os.environ["NVTE_UNFUSED_ATTN"] = "0"
if config.dropout_p == 0.0:
# test cuDNN FP8 dropout: need a FP16/BF16 reference on Blackwell
logging.info("[test_dpa_fp8_vs_f16]: run with fp8_dpa = False (FusedAttention)")
fused_attn_fwd_f16, fused_attn_bwd_f16 = _run_dpa_fp8_vs_f16(
dtype, config, False, qkv_layout, is_training, fp8_recipe
)

atol = 5e-1
rtol = 5e-2
rmse_tol = 0.11
bwd_names = ["dq", "dk", "dv"]
if flash_attn_supported:
if flash_attn_supported and fused_attn_supported_f16:
logging.debug("========== {:^25s} ==========".format("flash fp8 vs fused f16:"))
logging.debug("========== {:^25s} ==========".format("forward output"))
compare_and_assert(
Expand All @@ -2200,7 +2199,7 @@ def test_dpa_fp8_vs_f16(dtype, model, qkv_layout, fp8_dpa_bwd, is_training, scal
rmse_tol,
True,
)
if unfused_attn_supported:
if unfused_attn_supported and fused_attn_supported_f16:
logging.debug("========== {:^25s} ==========".format("unfused fp8 vs fused f16:"))
logging.debug("========== {:^25s} ==========".format("forward output"))
compare_and_assert(
Expand All @@ -2226,37 +2225,38 @@ def test_dpa_fp8_vs_f16(dtype, model, qkv_layout, fp8_dpa_bwd, is_training, scal
rmse_tol,
True,
)
if config.dropout_p != 0.0:
# test cuDNN FP8 dropout
assert torch.all(
fused_attn_fwd_fp8 == 1
), "fused_attn_fwd_fp8 must be all 1s when Q/K/V are all 1s."
else:
logging.debug("========== {:^25s} ==========".format("fused fp8 vs fused f16:"))
logging.debug("========== {:^25s} ==========".format("forward output"))
compare_and_assert(
fused_attn_fwd_fp8,
fused_attn_fwd_f16,
"fused_attn_fwd_fp8",
"fused_attn_fwd_f16",
atol,
rtol,
rmse_tol,
True,
)
if is_training:
for i, _ in enumerate(fused_attn_bwd_f16):
logging.debug("========== {:^25s} ==========".format(bwd_names[i]))
compare_and_assert(
fused_attn_bwd_fp8[i],
fused_attn_bwd_f16[i],
f"fused_attn_bwd_fp8[{i}]",
f"fused_attn_bwd_f16[{i}]",
atol,
rtol,
rmse_tol,
True,
)
if fused_attn_supported_fp8 and fused_attn_supported_f16:
if config.dropout_p != 0.0:
# test cuDNN FP8 dropout
assert torch.all(
fused_attn_fwd_fp8 == 1
), "fused_attn_fwd_fp8 must be all 1s when Q/K/V are all 1s."
else:
logging.debug("========== {:^25s} ==========".format("fused fp8 vs fused f16:"))
logging.debug("========== {:^25s} ==========".format("forward output"))
compare_and_assert(
fused_attn_fwd_fp8,
fused_attn_fwd_f16,
"fused_attn_fwd_fp8",
"fused_attn_fwd_f16",
atol,
rtol,
rmse_tol,
True,
)
if is_training:
for i, _ in enumerate(fused_attn_bwd_f16):
logging.debug("========== {:^25s} ==========".format(bwd_names[i]))
compare_and_assert(
fused_attn_bwd_fp8[i],
fused_attn_bwd_f16[i],
f"fused_attn_bwd_fp8[{i}]",
f"fused_attn_bwd_f16[{i}]",
atol,
rtol,
rmse_tol,
True,
)
os.environ["NVTE_UnfusedDPA_Emulate_FP8"] = "0"


Expand Down
Loading