Enable scaled FP8 (e4m3fn) KV cache on ROCm (AMD GPU) (#3290)

Co-authored-by: Gregory Shtrasberg <Gregory.Shtrasberg@amd.com>
Co-authored-by: HaiShaw <hixiao@gmail.com>
Co-authored-by: AdrianAbeyta <Adrian.Abeyta@amd.com>
Co-authored-by: Matthew Wong <Matthew.Wong2@amd.com>
Co-authored-by: root <root@gt-pla-u18-08.pla.dcgpu>
Co-authored-by: mawong-amd <156021403+mawong-amd@users.noreply.github.com>
Co-authored-by: ttbachyinsda <ttbachyinsda@outlook.com>
Co-authored-by: guofangze <guofangze@kuaishou.com>
Co-authored-by: Michael Goin <mgoin64@gmail.com>
Co-authored-by: jacobthebanana <50071502+jacobthebanana@users.noreply.github.com>
Co-authored-by: Woosuk Kwon <woosuk.kwon@berkeley.edu>

benchmarks/kernels/benchmark_paged_attention.py

@@ -97,6 +97,9 @@ def main(
             torch.cuda.cudart().cudaProfilerStart()
         start_time = time.perf_counter()
 
+        # Using default kv_scale
+        kv_scale = 1.0
+
         for _ in range(num_iters):
             if version == "v1":
                 ops.paged_attention_v1(
@@ -112,6 +115,7 @@ def main(
                     max_context_len,
                     alibi_slopes,
                     kv_cache_dtype,
+                    kv_scale,
                 )
             elif version == "v2":
                 ops.paged_attention_v2(
@@ -130,6 +134,7 @@ def main(
                     max_context_len,
                     alibi_slopes,
                     kv_cache_dtype,
+                    kv_scale,
                 )
             else:
                 raise ValueError(f"Invalid version: {version}")
@@ -179,11 +184,13 @@ if __name__ == '__main__':
     parser.add_argument(
         "--kv-cache-dtype",
         type=str,
-        choices=["auto", "fp8_e5m2"],
+        choices=["auto", "fp8"],
         default="auto",
         help=
-        'Data type for kv cache storage. If "auto", will use model data type.')
-    parser.add_argument("--device", type=str, choices=["cuda"], default="cuda")
+        'Data type for kv cache storage. If "auto", will use model data type. '
+        'FP8_E5M2 (without scaling) is only supported on cuda version greater '
+        'than 11.8. On ROCm (AMD GPU), FP8_E4M3 is instead supported for '
+        'common inference criteria.')
     args = parser.parse_args()
     print(args)