Support CE after grad acc fix (linkedin#375)

## Summary
<!--- This is a required section; please describe the main purpose of
this proposed code change. --->

<!---
## Details
This is an optional section; is there anything specific that reviewers
should be aware of?
--->
Based on linkedin#374, but make it
leaner
1. The use of cross entropy in model code has changed after grad fix
2. It changed from module CrossEntropy to functional cross_entropy
3. Our monkey patching needs to change accordingly
4. While also make sure backward compatibility by adding a condition for
different versions

Notable Changes

1. Add a functional api for CE to take keyword args
2. Add back conv test with logits to test CE convergence
3. Add back comp test for transformers 4.44

## Testing Done
<!--- This is a required section; please describe how this change was
tested. --->

<!-- 
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Complete the following tasks before sending your PR, and replace `[ ]`
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`[x]` to indicate you have done them. 
-->

- Hardware Type: <BLANK>
- [x] run `make test` to ensure correctness
- [x] run `make checkstyle` to ensure code style
- [x] run `make test-convergence` to ensure convergence

.github/workflows/ci.yml

@@ -61,6 +61,31 @@ jobs:
         python -m pip install --upgrade pip
         pip install modal
 
-    - name: Run unit tests
+    - name: Run tests
       run: |
         modal run dev.modal.tests
+
+  tests-bwd:
+    runs-on: ubuntu-latest
+    needs: [checkstyle]
+    env:
+      MODAL_TOKEN_ID: ${{ secrets.MODAL_TOKEN_ID }}
+      MODAL_TOKEN_SECRET: ${{ secrets.MODAL_TOKEN_SECRET }}
+
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@v3
+
+    - name: Set up Python
+      uses: actions/setup-python@v3
+      with:
+        python-version: '3.10'
+
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip
+        pip install modal
+
+    - name: Run tests
+      run: |
+        modal run dev.modal.tests_bwd

Makefile

@@ -20,8 +20,9 @@ checkstyle:
 # Command to run pytest for convergence tests
 # We have to explicitly set HF_DATASETS_OFFLINE=1, or dataset will silently try to send metrics and timeout (80s) https://github.com/huggingface/datasets/blob/37a603679f451826cfafd8aae00738b01dcb9d58/src/datasets/load.py#L286
 test-convergence:
-	HF_DATASETS_OFFLINE=1 python -m pytest --disable-warnings test/convergence
-
+	HF_DATASETS_OFFLINE=1 python -m pytest --disable-warnings test/convergence/test_mini_models.py
+	HF_DATASETS_OFFLINE=1 python -m pytest --disable-warnings test/convergence/test_mini_models_multimodal.py
+	HF_DATASETS_OFFLINE=1 python -m pytest --disable-warnings test/convergence/test_mini_models_with_logits.py
 
 # Command to run all benchmark scripts and update benchmarking data file
 # By default this doesn't overwrite existing data for the same benchmark experiment

dev/modal/tests_bwd.py

@@ -0,0 +1,28 @@
+from pathlib import Path
+
+import modal
+
+ROOT_PATH = Path(__file__).parent.parent.parent
+
+# tests_bwd is to ensure the backward compatibility of liger with older transformers
+image = (
+    modal.Image.debian_slim()
+    .pip_install_from_pyproject(
+        ROOT_PATH / "pyproject.toml", optional_dependencies=["dev"]
+    )
+    .pip_install("transformers==4.44.2")
+)
+
+app = modal.App("liger_tests", image=image)
+
+# mount: add local files to the remote container
+repo = modal.Mount.from_local_dir(ROOT_PATH, remote_path="/root/liger-kernel")
+
+
+@app.function(gpu="A10G", mounts=[repo], timeout=60 * 10)
+def liger_tests():
+    import subprocess
+
+    subprocess.run(["pip", "install", "-e", "."], check=True, cwd="/root/liger-kernel")
+    subprocess.run(["make", "test"], check=True, cwd="/root/liger-kernel")
+    subprocess.run(["make", "test-convergence"], check=True, cwd="/root/liger-kernel")

src/liger_kernel/transformers/functional.py

@@ -1,3 +1,5 @@
+from typing import Optional
+
 from liger_kernel.ops.cross_entropy import LigerCrossEntropyFunction
 from liger_kernel.ops.fused_linear_cross_entropy import (
     LigerFusedLinearCrossEntropyFunction,
@@ -13,7 +15,6 @@
 from liger_kernel.ops.swiglu import LigerSiLUMulFunction
 
 liger_swiglu = LigerSiLUMulFunction.apply
-liger_cross_entropy = LigerCrossEntropyFunction.apply
 liger_fused_linear_cross_entropy = LigerFusedLinearCrossEntropyFunction.apply
 liger_geglu = LigerGELUMulFunction.apply
 liger_rms_norm = LigerRMSNormFunction.apply
@@ -23,3 +24,33 @@
 liger_jsd = LigerJSDFunction.apply
 liger_fused_linear_jsd = LigerFusedLinearJSDFunction.apply
 liger_group_norm = LigerGroupNormFunction.apply
+
+
+# conform to the function signature in https://pytorch.org/docs/stable/generated/torch.nn.functional.cross_entropy.html
+# `weight` and `size_average` are placeholders and not implemented yet
+def liger_cross_entropy(
+    input,
+    target,
+    weight=None,
+    size_average=None,
+    ignore_index: int = -100,
+    reduce=None,
+    reduction: str = "mean",
+    label_smoothing: float = 0.0,
+    lse_square_scale: float = 0.0,
+    softcap: Optional[float] = None,
+    return_z_loss: bool = False,
+):
+    loss, z_loss = LigerCrossEntropyFunction.apply(
+        input,
+        target,
+        ignore_index,
+        lse_square_scale,
+        label_smoothing,
+        reduction,
+        softcap,
+        return_z_loss,
+    )
+    if not return_z_loss:
+        return loss
+    return loss, z_loss

src/liger_kernel/transformers/monkey_patch.py

@@ -8,6 +8,7 @@
 from transformers import PreTrainedModel
 
 from liger_kernel.transformers.cross_entropy import LigerCrossEntropyLoss
+from liger_kernel.transformers.functional import liger_cross_entropy
 from liger_kernel.transformers.geglu import LigerGEGLUMLP
 from liger_kernel.transformers.layer_norm import LigerLayerNorm
 from liger_kernel.transformers.model.gemma import lce_forward as gemma_lce_forward
@@ -111,8 +112,16 @@ def apply_liger_kernel_to_llama(
         modeling_llama.LlamaRMSNorm = LigerRMSNorm
     if swiglu:
         modeling_llama.LlamaMLP = LigerSwiGLUMLP
+
     if cross_entropy:
-        modeling_llama.CrossEntropyLoss = LigerCrossEntropyLoss
+        if transformer_version >= version.parse(SUPPORTED_TRANSFORMER_VERSION):
+            from transformers.loss.loss_utils import nn
+
+            nn.functional.cross_entropy = liger_cross_entropy
+        else:
+            logger.warning(TRANSFORMER_DEPRECATION_WARNING)
+            modeling_llama.CrossEntropyLoss = LigerCrossEntropyLoss
+
     if fused_linear_cross_entropy:
         if transformer_version >= version.parse(SUPPORTED_TRANSFORMER_VERSION):
             modeling_llama.LlamaForCausalLM.forward = llama_lce_forward
@@ -192,7 +201,13 @@ def apply_liger_kernel_to_mllama(
     if swiglu:
         modeling_mllama.MllamaTextMLP = LigerSwiGLUMLP
     if cross_entropy:
-        modeling_mllama.CrossEntropyLoss = LigerCrossEntropyLoss
+        if transformer_version >= version.parse(SUPPORTED_TRANSFORMER_VERSION):
+            from transformers.loss.loss_utils import nn
+
+            nn.functional.cross_entropy = liger_cross_entropy
+        else:
+            logger.warning(TRANSFORMER_DEPRECATION_WARNING)
+            modeling_mllama.CrossEntropyLoss = LigerCrossEntropyLoss
     if fused_linear_cross_entropy:
         if transformer_version >= version.parse(SUPPORTED_TRANSFORMER_VERSION):
             modeling_mllama.MllamaForCausalLM.forward = mllama_lce_forward
@@ -342,7 +357,14 @@ def apply_liger_kernel_to_mixtral(
     if rms_norm:
         modeling_mixtral.MixtralRMSNorm = LigerRMSNorm
     if cross_entropy:
-        modeling_mixtral.CrossEntropyLoss = LigerCrossEntropyLoss
+        if transformer_version >= version.parse(SUPPORTED_TRANSFORMER_VERSION):
+            from transformers.loss.loss_utils import nn
+
+            nn.functional.cross_entropy = liger_cross_entropy
+        else:
+            logger.warning(TRANSFORMER_DEPRECATION_WARNING)
+            modeling_mixtral.CrossEntropyLoss = LigerCrossEntropyLoss
+
     if fused_linear_cross_entropy:
         if transformer_version >= version.parse(SUPPORTED_TRANSFORMER_VERSION):
             modeling_mixtral.MixtralForCausalLM.forward = mixtral_lce_forward
@@ -417,7 +439,13 @@ def apply_liger_kernel_to_gemma(
     if rms_norm:
         modeling_gemma.GemmaRMSNorm = LigerRMSNormForGemma
     if cross_entropy:
-        modeling_gemma.CrossEntropyLoss = LigerCrossEntropyLoss
+        if transformer_version >= version.parse(SUPPORTED_TRANSFORMER_VERSION):
+            from transformers.loss.loss_utils import nn
+
+            nn.functional.cross_entropy = liger_cross_entropy
+        else:
+            logger.warning(TRANSFORMER_DEPRECATION_WARNING)
+            modeling_gemma.CrossEntropyLoss = LigerCrossEntropyLoss
     if geglu:
         modeling_gemma.GemmaMLP = LigerGEGLUMLP
     if fused_linear_cross_entropy:
@@ -474,6 +502,7 @@ def apply_liger_kernel_to_gemma2(
     assert not (
         cross_entropy and fused_linear_cross_entropy
     ), "cross_entropy and fused_linear_cross_entropy cannot both be True."
+
     from transformers.models.gemma2 import modeling_gemma2
     from transformers.models.gemma2.modeling_gemma2 import Gemma2Model
 
@@ -490,7 +519,13 @@ def apply_liger_kernel_to_gemma2(
         # https://github.com/huggingface/transformers/blob/v4.44.2/src/transformers/models/gemma/modeling_gemma.py#L109
         modeling_gemma2.Gemma2RMSNorm = LigerRMSNormForGemma2
     if cross_entropy:
-        modeling_gemma2.CrossEntropyLoss = LigerCrossEntropyLoss
+        if transformer_version >= version.parse(SUPPORTED_TRANSFORMER_VERSION):
+            from transformers.loss.loss_utils import nn
+
+            nn.functional.cross_entropy = liger_cross_entropy
+        else:
+            logger.warning(TRANSFORMER_DEPRECATION_WARNING)
+            modeling_gemma2.CrossEntropyLoss = LigerCrossEntropyLoss
     if fused_linear_cross_entropy:
         if transformer_version >= version.parse(SUPPORTED_TRANSFORMER_VERSION):
             modeling_gemma2.Gemma2ForCausalLM.forward = gemma2_lce_forward
@@ -562,8 +597,15 @@ def apply_liger_kernel_to_qwen2(
         modeling_qwen2.apply_rotary_pos_emb = liger_rotary_pos_emb
     if rms_norm:
         modeling_qwen2.Qwen2RMSNorm = LigerRMSNorm
+
     if cross_entropy:
-        modeling_qwen2.CrossEntropyLoss = LigerCrossEntropyLoss
+        if transformer_version >= version.parse(SUPPORTED_TRANSFORMER_VERSION):
+            from transformers.loss.loss_utils import nn
+
+            nn.functional.cross_entropy = liger_cross_entropy
+        else:
+            logger.warning(TRANSFORMER_DEPRECATION_WARNING)
+            modeling_qwen2.CrossEntropyLoss = LigerCrossEntropyLoss
 
     # import pdb; pdb.set_trace()
     if fused_linear_cross_entropy:
@@ -710,7 +752,13 @@ def apply_liger_kernel_to_phi3(
     if swiglu:
         modeling_phi3.Phi3MLP = LigerPhi3SwiGLUMLP
     if cross_entropy:
-        modeling_phi3.CrossEntropyLoss = LigerCrossEntropyLoss
+        if transformer_version >= version.parse(SUPPORTED_TRANSFORMER_VERSION):
+            from transformers.loss.loss_utils import nn
+
+            nn.functional.cross_entropy = liger_cross_entropy
+        else:
+            logger.warning(TRANSFORMER_DEPRECATION_WARNING)
+            modeling_phi3.CrossEntropyLoss = LigerCrossEntropyLoss
     if fused_linear_cross_entropy:
         if transformer_version >= version.parse(SUPPORTED_TRANSFORMER_VERSION):
             modeling_phi3.Phi3ForCausalLM.forward = phi3_lce_forward