From f62e8ac4708eb1c45b62aa53267704e4d080700c Mon Sep 17 00:00:00 2001
From: Harald Hoyer <harald@hoyer.xyz>
Date: Wed, 6 May 2026 09:13:54 +0200
Subject: [PATCH] perf(llama-cpp-rocm): tune for Strix Halo (gfx1151)
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- Restrict rocmGpuTargets to gfx1151 (Radeon 8060S, RDNA 3.5) — smaller
  closure, faster compile, no wasted device kernels.
- Enable GGML_HIP_ROCWMMA_FATTN: rocWMMA-backed flash attention is a
  major win on RDNA3+ for the GPU-offloaded attention path.
- Enable GGML_HIP_GRAPHS to lower per-token launch overhead.
- Add rocwmma to buildInputs to satisfy the WMMA path.

llama-server on halo runs with -ngl 99 --flash-attn on, so these flags
target the hot path. CPU-side AVX-512 was skipped intentionally — Zen 5
has it, but with full GPU offload the CPU paths barely run.
---
 overlays/unstable/default.nix | 39 ++++++++++++++++++++++++-----------
 1 file changed, 27 insertions(+), 12 deletions(-)

diff --git a/overlays/unstable/default.nix b/overlays/unstable/default.nix
index 9ec328e..4ba1183 100644
--- a/overlays/unstable/default.nix
+++ b/overlays/unstable/default.nix
@@ -12,18 +12,33 @@ final: prev: {
     # nodejs_20
     ;
 
-  llama-cpp-rocm = channels.unstable.llama-cpp-rocm.overrideAttrs (_: {
-    src = prev.fetchFromGitHub {
-      owner = "am17an";
-      repo = "llama.cpp";
-      rev = "267f8afe857b7bd1a49e4fde9138ab0f7be36625";
-      hash = "sha256-VYvRjnNZpPE60wjpBVO1FbURMRRMg71sM5kBxiEkElk=";
-      postFetch = ''
-        echo -n "267f8af" > $out/COMMIT
-      '';
-    };
-    npmDepsHash = "sha256-k62LIbyY2DXvs7XXbX0lNPiYxuYzeJUyQtS4eA+68f8=";
-  });
+  # Tuned for Strix Halo (Ryzen AI Max+ 395 / Radeon 8060S, gfx1151).
+  llama-cpp-rocm =
+    (channels.unstable.llama-cpp.override {
+      rocmSupport = true;
+      rocmGpuTargets = [ "gfx1151" ];
+    }).overrideAttrs
+      (prevAttrs: {
+        src = prev.fetchFromGitHub {
+          owner = "am17an";
+          repo = "llama.cpp";
+          rev = "267f8afe857b7bd1a49e4fde9138ab0f7be36625";
+          hash = "sha256-VYvRjnNZpPE60wjpBVO1FbURMRRMg71sM5kBxiEkElk=";
+          postFetch = ''
+            echo -n "267f8af" > $out/COMMIT
+          '';
+        };
+        npmDepsHash = "sha256-k62LIbyY2DXvs7XXbX0lNPiYxuYzeJUyQtS4eA+68f8=";
+
+        buildInputs = (prevAttrs.buildInputs or [ ]) ++ [
+          channels.unstable.rocmPackages.rocwmma
+        ];
+
+        cmakeFlags = (prevAttrs.cmakeFlags or [ ]) ++ [
+          "-DGGML_HIP_ROCWMMA_FATTN=ON"
+          "-DGGML_HIP_GRAPHS=ON"
+        ];
+      });
 
   /*
     gnome-remote-desktop = channels.unstable.gnome-remote-desktop.overrideAttrs (prevAttrs: {