[PyTorch] ONNX export of FP8 Current Scaling

docs/examples/onnx/onnx_export.ipynb

@@ -10,7 +10,7 @@
     "\n",
     "<b>Note:</b>\n",
     "\n",
-    "Currently, export to ONNX is supported only for high precision, FP8 delayed scaling and MXFP8.\n",
+    "Currently, export to ONNX is supported only for high precision, FP8 delayed scaling, FP8 current scaling and MXFP8.\n",
     "\n",
     "</div>\n",
     "\n",

tests/pytorch/test_onnx_export.py

@@ -64,6 +64,7 @@
     fp8_recipes.append(recipe.MXFP8BlockScaling())
 if fp8_available:
     fp8_recipes.append(recipe.DelayedScaling())
+    fp8_recipes.append(recipe.Float8CurrentScaling())
 fp8_recipes.append(None)
 
 supported_activations = ["gelu", "relu", "reglu", "geglu", "swiglu"]
@@ -80,11 +81,11 @@
     ],
     outputs=[PyCustomOpDef.dt_uint8],
 )
-def trt_fp8_quantize(t, scale):
+def trt_fp8_quantize(t, scale_inv):
     """FP8 quantization extension for ONNX Runtime."""
     x = torch.from_numpy(t).cuda()
     q = te.tensor.float8_tensor.Float8Quantizer(
-        scale=1 / torch.from_numpy(scale).cuda(),
+        scale=1 / torch.from_numpy(scale_inv).cuda(),
         amax=torch.zeros([1]).cuda(),
         fp8_dtype=tex.DType.kFloat8E4M3,
     )
@@ -100,11 +101,11 @@ def trt_fp8_quantize(t, scale):
     ],
     outputs=[PyCustomOpDef.dt_float],
 )
-def trt_fp8_dequantize(t, scale):
+def trt_fp8_dequantize(t, scale_inv):
     """FP8 dequantization extension for ONNX Runtime."""
     x = torch.from_numpy(t).cuda()
     q = te.tensor.float8_tensor.Float8Quantizer(
-        scale=1 / torch.from_numpy(scale).cuda(),
+        scale=1 / torch.from_numpy(scale_inv).cuda(),
         amax=torch.zeros([1]).cuda(),
         fp8_dtype=tex.DType.kFloat8E4M3,
     )
@@ -592,7 +593,9 @@ def _test_export_layernorm_linear(
                     fname,
                     inp,
                     model,
-                    atol=1e-3,
+                    # For current scaling we use Float8Quantizer in tests + amax computed by hand,
+                    # which has slightly different numerics than Float8CurrentScalingQuantizer.
+                    atol=1e-3 if fp8_recipe.__class__ is not recipe.Float8CurrentScaling else 2e-2,
                     is_fp8=fp8_recipe is not None,
                     te_outputs=te_outputs,
                 )

transformer_engine/pytorch/onnx_extensions.py

@@ -112,7 +112,9 @@ def onnx_quantize_fp8_symbolic(
     doc="TRT FP8 Quantize Linear used for inference.",
     inputs=[
         defs.OpSchema.FormalParameter("tensor", "tensor(float)", "Input tensor to quantize"),
-        defs.OpSchema.FormalParameter("scale", "tensor(float)", "Scale factor for quantization"),
+        defs.OpSchema.FormalParameter(
+            "scale_inv", "tensor(float)", "Inverse scale factor for quantization"
+        ),
     ],
     outputs=[defs.OpSchema.FormalParameter("output", "tensor(uint8)", "Quantized output tensor")],
 )
@@ -157,7 +159,9 @@ def onnx_dequantize_fp8_symbolic(
     doc="TRT FP8 Dequantize Linear from Float8Tensor used for inference.",
     inputs=[
         defs.OpSchema.FormalParameter("tensor", "tensor(uint8)", "Input tensor to dequantize"),
-        defs.OpSchema.FormalParameter("scale", "tensor(float)", "Scale factor for dequantization"),
+        defs.OpSchema.FormalParameter(
+            "scale_inv", "tensor(float)", "Inverse scale factor for dequantization"
+        ),
     ],
     outputs=[defs.OpSchema.FormalParameter("output", "tensor(float)", "Dequantized output tensor")],
 )
@@ -166,6 +170,68 @@ def onnx_dequantize_fp8_symbolic(
     opset=trt_opset, name="TRT_FP8DequantizeLinear", op_schema=schema
 )
 
+# ONNX FP8 Current Scaling Quantization
+
+
+@torch.library.custom_op("tex::fp8_cs_quantize", mutates_args=[])
+def onnx_cs_quantize_fp8_op(tensor: torch.Tensor) -> Tuple[torch.Tensor, torch.Tensor]:
+    """Quantize to FP8 with current scaling; returns (uint8, scale_inv)."""
+    if tensor.dtype != torch.float32:
+        tensor = tensor.to(torch.float32)
+    amax = tensor.abs().max()
+    eps = torch.tensor(1e-12, dtype=torch.float32, device=tensor.device)
+    amax = torch.maximum(amax, eps)
+    fp8_max = torch.tensor(448, dtype=torch.float32, device=tensor.device)
+    scale = fp8_max / amax
+    q = torch.ops.tex.fp8_quantize(tensor, scale)
+    scale_inv = 1 / scale
+    return q, scale_inv
+
+
+@onnx_cs_quantize_fp8_op.register_fake
+def _(tensor: torch.Tensor) -> Tuple[torch.Tensor, torch.Tensor]:
+    return torch.empty(tensor.shape, dtype=torch.uint8, device=tensor.device), torch.ones(
+        1, dtype=torch.float32, device=tensor.device
+    )
+
+
+def onnx_quantize_fp8_cs_symbolic(
+    tensor: onnxscript.onnx_types.TensorType,
+):
+    """Symbolic quantize with current scaling; computes scale_inv from tensor."""
+    # scale_inv = 1 / max(abs(tensor))
+    amax = op.ReduceMax(op.Abs(tensor), keepdims=0)
+    eps = op.Constant(value_float=1.0e-12)
+    amax = op.Max(amax, eps)
+    scale_inv = op.Div(amax, op.Constant(value_float=448.0))
+    q = TRT_FP8QuantizeLinear(tensor, scale_inv)
+    return q, scale_inv
+
+
+# ONNX FP8 Current Scaling Dequantization
+
+
+@torch.library.custom_op("tex::fp8_cs_dequantize", mutates_args=[])
+def onnx_cs_dequantize_fp8_op(tensor: torch.Tensor, scale_inv: torch.Tensor) -> torch.Tensor:
+    """Dequantize FP8 with provided dynamic scale_inv."""
+    quantizer = Float8Quantizer(
+        1 / scale_inv.to(torch.float32), torch.zeros(1).to(tensor.device), tex.DType.kFloat8E4M3
+    )
+    quantizer_tensor = quantizer.create_tensor_from_data(tensor, fake_dtype=torch.float32)
+    return quantizer_tensor.dequantize()
+
+
+@onnx_cs_dequantize_fp8_op.register_fake
+def _(tensor: torch.Tensor, _) -> torch.Tensor:
+    return torch.empty(tensor.shape, dtype=torch.float32, device=tensor.device)
+
+
+def onnx_dequantize_fp8_cs_symbolic(
+    tensor: onnxscript.onnx_types.UINT8, scale_inv: onnxscript.onnx_types.TensorType
+) -> onnxscript.onnx_types.TensorType:
+    """Symbolic dequantize with current scaling."""
+    return TRT_FP8DequantizeLinear(tensor, scale_inv)
+
 
 # ONNX MXFP8 Quantization
 
@@ -356,6 +422,8 @@ def onnx_attention_mask_func(
     torch.ops.tex.gemm_inf.default: onnx_gemm_inf_symbolic,
     torch.ops.tex.fp8_quantize.default: onnx_quantize_fp8_symbolic,
     torch.ops.tex.fp8_dequantize.default: onnx_dequantize_fp8_symbolic,
+    torch.ops.tex.fp8_cs_quantize.default: onnx_quantize_fp8_cs_symbolic,
+    torch.ops.tex.fp8_cs_dequantize.default: onnx_dequantize_fp8_cs_symbolic,
     torch.ops.tex.mxfp8_quantize.default: onnx_quantize_mxfp8_symbolic,
     torch.ops.tex.mxfp8_dequantize.default: onnx_dequantize_mxfp8_symbolic,
     torch.ops.tex.layernorm.default: onnx_layernorm_symbolic,

transformer_engine/pytorch/tensor/float8_tensor.py

@@ -350,15 +350,25 @@ def create_tensor_from_data(
 
     def onnx_quantize(self, tensor: torch.Tensor) -> QuantizedTensor:
         """Function using primitives with ONNX defined translations."""
-        raise NotImplementedError(
-            "Float8CurrentScalingQuantizer does not support ONNX quantization yet."
+        if tensor.dtype != torch.float32:
+            tensor = tensor.to(torch.float32)
+        data, scale_inv = torch.ops.tex.fp8_cs_quantize(tensor)
+        return Float8Tensor(
+            shape=data.shape,
+            dtype=torch.float32,
+            data=data,
+            fp8_scale_inv=scale_inv,
+            fp8_dtype=self.dtype,
+            requires_grad=False,
+            data_transpose=None,
+            quantizer=self,
         )
 
     def onnx_dequantize(self, tensor: QuantizedTensor) -> torch.Tensor:
         """Function using primitives with ONNX defined translations."""
-        raise NotImplementedError(
-            "Float8CurrentScalingQuantizer does not support ONNX dequantization yet."
-        )
+        out = torch.ops.tex.fp8_cs_dequantize(tensor._data, tensor._scale_inv)
+        out = out.to(tensor.dtype)
+        return out
 
     def _canonicalized_amax_reduction_group(self) -> dist_group_type:
         """Get process group for amax reduction"""