[Test] Enhance JIT kvcache store kernel test coverage (#19630)

python/sglang/jit_kernel/tests/test_store_cache.py

@@ -3,7 +3,7 @@ import itertools
 import pytest
 import torch
 
-from sglang.jit_kernel.kvcache import store_cache
+from sglang.jit_kernel.kvcache import can_use_store_cache, store_cache
 
 BS_LIST = [2**n for n in range(0, 15)]
 BS_LIST += [x + 1 + i for i, x in enumerate(BS_LIST)]
@@ -31,5 +31,93 @@ def test_store_cache(batch_size: int, element_dim: int) -> None:
     assert torch.all(v_cache[indices] == v)
 
 
+# Smaller subset for targeted tests below
+REPR_BS = [1, 7, 128]
+REPR_DIMS = [64, 128, 512, 1024, 96]
+SMALL_CACHE = 4096
+
+
+@pytest.mark.parametrize("dtype", [torch.float16, torch.bfloat16, torch.float32])
+@pytest.mark.parametrize(
+    "batch_size,element_dim",
+    list(itertools.product(REPR_BS, REPR_DIMS)),
+)
+def test_store_cache_dtypes(
+    batch_size: int, element_dim: int, dtype: torch.dtype
+) -> None:
+    k = torch.randn((batch_size, element_dim), dtype=dtype, device=DEVICE)
+    v = torch.randn((batch_size, element_dim), dtype=dtype, device=DEVICE)
+    k_cache = torch.randn((SMALL_CACHE, element_dim), dtype=dtype, device=DEVICE)
+    v_cache = torch.randn((SMALL_CACHE, element_dim), dtype=dtype, device=DEVICE)
+    indices = torch.randperm(SMALL_CACHE, device=DEVICE)[:batch_size]
+
+    store_cache(k, v, k_cache, v_cache, indices)
+
+    assert torch.all(k_cache[indices] == k)
+    assert torch.all(v_cache[indices] == v)
+
+
+@pytest.mark.parametrize(
+    "batch_size,element_dim",
+    list(itertools.product(REPR_BS, REPR_DIMS)),
+)
+def test_store_cache_int32_indices(batch_size: int, element_dim: int) -> None:
+    k = torch.randn((batch_size, element_dim), dtype=DTYPE, device=DEVICE)
+    v = torch.randn((batch_size, element_dim), dtype=DTYPE, device=DEVICE)
+    k_cache = torch.randn((SMALL_CACHE, element_dim), dtype=DTYPE, device=DEVICE)
+    v_cache = torch.randn((SMALL_CACHE, element_dim), dtype=DTYPE, device=DEVICE)
+    # int32 indices exercise a different CUDA template instantiation than default int64
+    indices = torch.randperm(SMALL_CACHE, device=DEVICE)[:batch_size].to(torch.int32)
+
+    store_cache(k, v, k_cache, v_cache, indices)
+
+    assert torch.all(k_cache[indices.long()] == k)
+    assert torch.all(v_cache[indices.long()] == v)
+
+
+def _valid_num_splits(element_dim: int, dtype: torch.dtype) -> list:
+    """Return the list of valid num_split values for a given element_dim/dtype."""
+    row_bytes = element_dim * dtype.itemsize
+    splits = [1]
+    if row_bytes % (2 * 128) == 0:
+        splits.append(2)
+    if row_bytes % (4 * 128) == 0:
+        splits.append(4)
+    return splits
+
+
+_NUM_SPLIT_CASES = [
+    (_dim, _ns, _dtype)
+    for _dtype in [torch.float16, torch.bfloat16, torch.float32]
+    for _dim in REPR_DIMS
+    for _ns in _valid_num_splits(_dim, _dtype)
+]
+
+
+@pytest.mark.parametrize("element_dim,num_split,dtype", _NUM_SPLIT_CASES)
+def test_store_cache_num_split(
+    element_dim: int, num_split: int, dtype: torch.dtype
+) -> None:
+    batch_size = 128
+    k = torch.randn((batch_size, element_dim), dtype=dtype, device=DEVICE)
+    v = torch.randn((batch_size, element_dim), dtype=dtype, device=DEVICE)
+    k_cache = torch.randn((SMALL_CACHE, element_dim), dtype=dtype, device=DEVICE)
+    v_cache = torch.randn((SMALL_CACHE, element_dim), dtype=dtype, device=DEVICE)
+    indices = torch.randperm(SMALL_CACHE, device=DEVICE)[:batch_size]
+
+    # Verify each num_split kernel path (1, 2, 4) produces correct results
+    store_cache(k, v, k_cache, v_cache, indices, num_split=num_split)
+
+    assert torch.all(k_cache[indices] == k)
+    assert torch.all(v_cache[indices] == v)
+
+
+def test_can_use_store_cache() -> None:
+    assert can_use_store_cache(128)
+    assert can_use_store_cache(256)
+    assert can_use_store_cache(1024)
+    assert can_use_store_cache(2048)
+
+
 if __name__ == "__main__":
     pytest.main([__file__, "-v", "-s"])