From 237ac976982e3efa4ae4339b1fe9344c81316b28 Mon Sep 17 00:00:00 2001
From: Artur Skowronski <me@arturskowronski.com>
Date: Tue, 7 Apr 2026 23:20:30 +0200
Subject: [PATCH] feat: add Apple Metal backend support to llama-tornado
 launcher

Add --metal flag to enable running GPULlama3 with TornadoVM's Metal
backend on macOS. This requires TornadoVM 4.0+ which ships the Metal
driver (tornado.drivers.metal).

Tested on Apple M1 Pro with TornadoVM 4.0.0-jdk21 Metal SDK.
---
 llama-tornado | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/llama-tornado b/llama-tornado
index 57a50f1c..a49542f7 100755
--- a/llama-tornado
+++ b/llama-tornado
@@ -19,6 +19,7 @@ from enum import Enum
 class Backend(Enum):
     OPENCL = "opencl"
     PTX = "ptx"
+    METAL = "metal"
 
 
 class LlamaRunner:
@@ -168,6 +169,14 @@ class LlamaRunner:
                     "ALL-SYSTEM,jdk.incubator.vector,tornado.runtime,tornado.annotation,tornado.drivers.common,tornado.drivers.ptx",
                 ]
             )
+        elif args.backend == Backend.METAL:
+            module_config.extend(
+                [
+                    f"@{self.tornado_sdk}/etc/exportLists/metal-exports",
+                    "--add-modules",
+                    "ALL-SYSTEM,jdk.incubator.vector,tornado.runtime,tornado.annotation,tornado.drivers.common,tornado.drivers.metal",
+                ]
+            )
 
         module_config.extend(
             [
@@ -410,6 +419,13 @@ def create_parser() -> argparse.ArgumentParser:
         const=Backend.PTX,
         help="Use PTX/CUDA backend",
     )
+    hw_group.add_argument(
+        "--metal",
+        dest="backend",
+        action="store_const",
+        const=Backend.METAL,
+        help="Use Apple Metal backend (macOS only, requires TornadoVM 4.0+)",
+    )
     hw_group.add_argument("--gpu-memory", default="14GB", help="GPU memory allocation")
     hw_group.add_argument("--heap-min", default="20g", help="Minimum JVM heap size")
     hw_group.add_argument("--heap-max", default="20g", help="Maximum JVM heap size")