Fix batch invariant ops (#11368)

python/sglang/srt/batch_invariant_ops/batch_invariant_ops.py

@@ -77,8 +77,6 @@ def matmul_kernel_persistent(
     k_tiles = tl.cdiv(K, BLOCK_SIZE_K)
     num_tiles = num_pid_m * num_pid_n
 
-    tile_id_c = start_pid - NUM_SMS
-
     offs_k_for_mask = tl.arange(0, BLOCK_SIZE_K)
     num_pid_in_group = GROUP_SIZE_M * num_pid_n
 
@@ -120,10 +118,6 @@ def matmul_kernel_persistent(
             )
             accumulator = tl.dot(a, b, accumulator)
 
-        tile_id_c += NUM_SMS
-        pid_m, pid_n = _compute_pid(
-            tile_id_c, num_pid_in_group, num_pid_m, GROUP_SIZE_M, NUM_SMS
-        )
         offs_cm = pid_m * BLOCK_SIZE_M + tl.arange(0, BLOCK_SIZE_M)
         offs_cn = pid_n * BLOCK_SIZE_N + tl.arange(0, BLOCK_SIZE_N)
         if C_LARGE:
@@ -137,6 +131,10 @@ def matmul_kernel_persistent(
             accumulator += bias
         if c_ptr.dtype.element_ty == tl.float8e4nv:
             c = accumulator.to(tl.float8e4nv)
+        elif c_ptr.dtype.element_ty == tl.bfloat16:
+            c = accumulator.to(tl.bfloat16)
+        elif c_ptr.dtype.element_ty == tl.float32:
+            c = accumulator.to(tl.float32)
         else:
             c = accumulator.to(tl.float16)
         tl.store(c_ptrs, c, mask=c_mask)

test/srt/batch_invariant/test_batch_invariant_ops.py

+# Adapted from https://github.com/thinking-machines-lab/batch_invariant_ops/blob/main/test_batch_invariance.py
+import math
+import unittest
+
+import torch
+
+from sglang.srt.batch_invariant_ops.batch_invariant_ops import set_batch_invariant_mode
+from sglang.test.test_utils import CustomTestCase
+
+device_type = getattr(torch.accelerator.current_accelerator(), "type", "cpu")
+torch.set_default_device(device_type)
+
+# Just to get the logging out of the way
+with set_batch_invariant_mode(True):
+    pass
+
+
+class TestBatchInvariantOps(CustomTestCase):
+    def _test_batch_invariance(self, M, K, N, dtype):
+        """
+        Test that matrix operations produce identical results for:
+        - Method 1: Matrix-vector multiplication (batch size 1)
+        - Method 2: Matrix-matrix multiplication, then slice (full batch)
+        """
+        a = torch.linspace(-100, 100, M * K, dtype=dtype).reshape(M, K)
+
+        # Create non-contiguous tensor
+        b = torch.linspace(-100, 100, K * N, dtype=dtype).reshape(N, K)
+        b = b.transpose(0, 1)
+
+        # Method 1: Matrix-vector multiplication (batch size 1)
+        out1 = torch.mm(a[:1], b)
+
+        # Method 2: Matrix-matrix multiplication, then slice (full batch)
+        out2_pre = torch.mm(a, b)
+        out2 = out2_pre[:1]
+
+        # Check if results are identical
+        diff = (out1 - out2).abs().max()
+        return diff.item()
+
+    def _run_multiple_iterations(self, iters, M, K, N, dtype):
+        """Run multiple iterations and collect diff statistics"""
+        difflist = []
+        for _ in range(iters):
+            diff = self._test_batch_invariance(M, K, N, dtype)
+            difflist.append(diff)
+        return difflist
+
+    def _assert_batch_invariant_results(self, difflist, dtype, test_name):
+        """
+        Assert that in batch-invariant mode:
+        1. All diffs must not be NaN
+        2. All diffs must be exactly 0
+        3. Max, min, and diff of diffs must all be 0
+        """
+        max_diff = max(difflist)
+        min_diff = min(difflist)
+        diff_range = max_diff - min_diff
+
+        # Check for NaN values
+        self.assertFalse(
+            math.isnan(max_diff), f"{test_name}: max_diff is NaN for {dtype}"
+        )
+        self.assertFalse(
+            math.isnan(min_diff), f"{test_name}: min_diff is NaN for {dtype}"
+        )
+        self.assertFalse(
+            math.isnan(diff_range), f"{test_name}: diff_range is NaN for {dtype}"
+        )
+
+        # Check that all diffs are exactly 0
+        self.assertEqual(
+            max_diff,
+            0.0,
+            f"{test_name}: max_diff must be 0 in batch-invariant mode, got {max_diff} for {dtype}",
+        )
+        self.assertEqual(
+            min_diff,
+            0.0,
+            f"{test_name}: min_diff must be 0 in batch-invariant mode, got {min_diff} for {dtype}",
+        )
+        self.assertEqual(
+            diff_range,
+            0.0,
+            f"{test_name}: diff_range must be 0 in batch-invariant mode, got {diff_range} for {dtype}",
+        )
+
+    def test_small_matrices(self):
+        """Test batch invariance with small matrix sizes"""
+        test_cases = [
+            ("Small-1", 8, 64, 128),
+            ("Small-2", 16, 128, 256),
+            ("Small-3", 4, 32, 64),
+        ]
+
+        for name, M, K, N in test_cases:
+            with self.subTest(name=name, M=M, K=K, N=N):
+                for dtype in [torch.float32, torch.bfloat16]:
+                    with self.subTest(dtype=dtype):
+                        # Run with batch-invariant mode
+                        with set_batch_invariant_mode(True):
+                            difflist = self._run_multiple_iterations(
+                                iters=5, M=M, K=K, N=N, dtype=dtype
+                            )
+                            self._assert_batch_invariant_results(difflist, dtype, name)
+
+    def test_medium_matrices(self):
+        """Test batch invariance with medium matrix sizes"""
+        test_cases = [
+            ("Medium-1", 32, 128, 1024),
+            ("Medium-2", 64, 512, 2048),
+            ("Medium-3", 24, 192, 768),
+        ]
+
+        for name, M, K, N in test_cases:
+            with self.subTest(name=name, M=M, K=K, N=N):
+                for dtype in [torch.float32, torch.bfloat16]:
+                    with self.subTest(dtype=dtype):
+                        # Run with batch-invariant mode
+                        with set_batch_invariant_mode(True):
+                            difflist = self._run_multiple_iterations(
+                                iters=5, M=M, K=K, N=N, dtype=dtype
+                            )
+                            self._assert_batch_invariant_results(difflist, dtype, name)
+
+    def test_large_matrices(self):
+        """Test batch invariance with large matrix sizes"""
+        test_cases = [
+            ("Large-1", 128, 1024, 4096),
+            ("Large-2", 256, 2048, 8192),
+            ("Large-3", 96, 768, 3072),
+        ]
+
+        for name, M, K, N in test_cases:
+            with self.subTest(name=name, M=M, K=K, N=N):
+                for dtype in [torch.float32, torch.bfloat16]:
+                    with self.subTest(dtype=dtype):
+                        # Run with batch-invariant mode
+                        with set_batch_invariant_mode(True):
+                            difflist = self._run_multiple_iterations(
+                                iters=5, M=M, K=K, N=N, dtype=dtype
+                            )
+                            self._assert_batch_invariant_results(difflist, dtype, name)
+
+    def test_without_batch_invariant_mode(self):
+        """
+        Test that without batch-invariant mode, results may differ.
+        This test demonstrates the difference batch-invariant mode makes.
+        """
+        M, K, N = 32, 128, 1024
+        dtype = torch.float32
+
+        # Run without batch-invariant mode
+        with set_batch_invariant_mode(False):
+            difflist = self._run_multiple_iterations(
+                iters=5, M=M, K=K, N=N, dtype=dtype
+            )
+            print(f"Without batch-invariant mode, we get diffs: {difflist}")
+
+
+if __name__ == "__main__":
+    unittest.main()

test/srt/run_suite.py

@@ -33,6 +33,7 @@ suites = {
         TestFile("models/test_generation_models.py", 103),
         TestFile("models/test_nvidia_nemotron_nano_v2.py", 180),
         TestFile("models/test_qwen_models.py", 82),
+        TestFile("batch_invariant/test_batch_invariant_ops.py", 10),
         TestFile("models/test_reward_models.py", 132),
         TestFile("models/test_transformers_models.py", 320),
         TestFile("models/test_vlm_models.py", 741),