added rocm custom paged attention.

Ported ROCm/vllm changes to upstream vLLM

This commit manually ports changes from ROCm/vllm (ROCm#372) to upstream vLLM.
The original work was done by sanyalington.

Co-authored-by: sanyalington <shomy.sanyal@amd.com>

Signed-off-by: vllmellm <vllm.ellm@embeddedllm.com>

Author: vllmellm

benchmarks/kernels/benchmark_paged_attention.py

@@ -9,8 +9,9 @@
 from vllm.utils import (STR_DTYPE_TO_TORCH_DTYPE, FlexibleArgumentParser,
                         create_kv_caches_with_random)
 
-NUM_BLOCKS = 1024
+NUM_BLOCKS = 128 * 1024
 PARTITION_SIZE = 512
+PARTITION_SIZE_ROCM = 256
 
 
 @torch.inference_mode()
@@ -78,6 +79,12 @@ def main(
     # Prepare for the paged attention kernel.
     output = torch.empty_like(query)
     if version == "v2":
+        if current_platform.is_rocm():
+            global PARTITION_SIZE
+            if not args.custom_paged_attn:
+                PARTITION_SIZE = 1024
+            else:
+                PARTITION_SIZE = PARTITION_SIZE_ROCM
         num_partitions = ((max_seq_len + PARTITION_SIZE - 1) // PARTITION_SIZE)
         tmp_output = torch.empty(
             size=(num_seqs, num_query_heads, num_partitions, head_size),
@@ -119,25 +126,48 @@ def run_cuda_benchmark(num_iters: int, profile: bool = False) -> float:
                     v_scale,
                 )
             elif version == "v2":
-                ops.paged_attention_v2(
-                    output,
-                    exp_sums,
-                    max_logits,
-                    tmp_output,
-                    query,
-                    key_cache,
-                    value_cache,
-                    num_kv_heads,
-                    scale,
-                    block_tables,
-                    seq_lens,
-                    block_size,
-                    max_seq_len,
-                    alibi_slopes,
-                    kv_cache_dtype,
-                    k_scale,
-                    v_scale,
-                )
+                if not args.custom_paged_attn:
+                    ops.paged_attention_v2(
+                        output,
+                        exp_sums,
+                        max_logits,
+                        tmp_output,
+                        query,
+                        key_cache,
+                        value_cache,
+                        num_kv_heads,
+                        scale,
+                        block_tables,
+                        seq_lens,
+                        block_size,
+                        max_seq_len,
+                        alibi_slopes,
+                        kv_cache_dtype,
+                        k_scale,
+                        v_scale,
+                    )
+                else:
+                    ops.paged_attention_rocm(
+                        output,
+                        exp_sums,
+                        max_logits,
+                        tmp_output,
+                        query,
+                        key_cache,
+                        value_cache,
+                        num_kv_heads,
+                        scale,
+                        block_tables,
+                        seq_lens,
+                        block_size,
+                        max_seq_len,
+                        alibi_slopes,
+                        kv_cache_dtype,
+                        k_scale,
+                        v_scale,
+                        None,
+                        PARTITION_SIZE,
+                    )
             else:
                 raise ValueError(f"Invalid version: {version}")
         torch.cuda.synchronize()
@@ -191,6 +221,9 @@ def run_cuda_benchmark(num_iters: int, profile: bool = False) -> float:
         help="Data type for kv cache storage. If 'auto', will use model "
         "data type. CUDA 11.8+ supports fp8 (=fp8_e4m3) and fp8_e5m2. "
         "ROCm (AMD GPU) supports fp8 (=fp8_e4m3)")
+    parser.add_argument("--custom-paged-attn",
+                        action="store_true",
+                        help="Use custom paged attention")
     args = parser.parse_args()
     print(args)