unify chunk benchmark (#28892)

Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/28892

as title

Test Plan:
```
buck run mode/opt //caffe2/benchmarks/operator_benchmark/pt:chunk_test
# ----------------------------------------
# PyTorch/Caffe2 Operator Micro-benchmarks
# ----------------------------------------
# Tag : short

# Benchmarking PyTorch: chunks
# Mode: Eager
# Name: chunks_M256_N512_chunks2_cpu
# Input: M: 256, N: 512, chunks: 2, device: cpu
Forward Execution Time (us) : 4.098

Reviewed By: hl475

Differential Revision: D18227499

fbshipit-source-id: 72268b7fe94a7d92d6e47f58f33902a33367c68b
diff --git a/benchmarks/operator_benchmark/pt/chunk_test.py b/benchmarks/operator_benchmark/pt/chunk_test.py
index 0c3fde1..f30c8b9 100644
--- a/benchmarks/operator_benchmark/pt/chunk_test.py
+++ b/benchmarks/operator_benchmark/pt/chunk_test.py
@@ -11,17 +11,30 @@
 
 
 # Configs for PT Chunk operator
-chunks_short_configs = op_bench.cross_product_configs(
-    M=[256, 512],
-    N=[512],
-    chunks=[2],
-    tags=['short']
+chunk_short_configs = op_bench.config_list(
+    attr_names=["M", "N", "chunks"],
+    attrs=[
+        [256, 512, 2],
+        [512, 512, 2],
+    ],
+    cross_product_configs={
+        'device': ['cpu'],
+    },
+    tags=["short"],
+)
+
+chunks_long_configs = op_bench.cross_product_configs(
+    M=[128, 1024],
+    N=[128, 1024],
+    chunks=[2, 4],
+    device=['cpu'],
+    tags=['long']
 )
 
 
 class ChunkBenchmark(op_bench.TorchBenchmarkBase):
-    def init(self, M, N, chunks):
-        self.input_one = torch.rand(M, N)
+    def init(self, M, N, chunks, device):
+        self.input_one = torch.rand(M, N, device=device)
         self.chunks = chunks
         self.set_module_name('chunks')
 
@@ -29,7 +42,8 @@
         return torch.chunk(self.input_one, self.chunks)
 
 
-op_bench.generate_pt_test(chunks_short_configs, ChunkBenchmark)
+op_bench.generate_pt_test(chunk_short_configs + chunks_long_configs,
+                          ChunkBenchmark)
 
 
 if __name__ == "__main__":