Commit 3e390af18 for llama.cpp

commit 3e390af18de1131dda27913c00511725b4274c8a
Author: Ruben Ortlam <rortlam@redhat.com>
Date:   Thu Oct 15 05:26:10 2026 +0200

    vulkan: Use L2-friendly workgroup scheduling for cm2 mulmat (#30215)

diff --git a/ggml/src/ggml-vulkan/vulkan-shaders/mul_mm_cm2.comp b/ggml/src/ggml-vulkan/vulkan-shaders/mul_mm_cm2.comp
index 89022f047..10dda7768 100644
--- a/ggml/src/ggml-vulkan/vulkan-shaders/mul_mm_cm2.comp
+++ b/ggml/src/ggml-vulkan/vulkan-shaders/mul_mm_cm2.comp
@@ -45,6 +45,7 @@ const uint BNover2 = BN / 2;
 const uint BNover4 = enable_smaller_matrices ? (BN / 4) : (BN / 2);
 layout (constant_id = 5) const uint ALIGNED = 0;
 layout (constant_id = 6) const uint subgroup_size = 32;
+#define GROUP_A_BUDGET (8u * 1024u * 1024u)

 #ifdef MULMAT_QUANT

@@ -258,8 +259,6 @@ void main() {
     const uint row_begin = tile_idx * BN;
     _ne1 = data_row_map[2 + 2 * tile_idx];
     const uint ic = 0;
-#else
-    const uint ic = gl_WorkGroupID.y;
 #endif

 #ifdef MUL_MAT_ID
@@ -289,9 +288,33 @@ void main() {
 #endif

     const uint blocks_m = (p.M + BM - 1) / BM;
-    const uint ir = gl_WorkGroupID.x % blocks_m;
     const uint ik = gl_WorkGroupID.x / blocks_m;

+#ifdef MUL_MAT_ID
+    const uint ir = gl_WorkGroupID.x % blocks_m;
+#else
+    // L2-friendly workgroup scheduling
+    const uint blocks_n = (p.N + BN - 1) / BN;
+#if defined(MULMAT_QUANT)
+    const uint a_panel_bytes = (BM * p.K / mm_quant_k()) * MmABlockBytes;
+#elif defined(DATA_A_F32)
+    const uint a_panel_bytes = BM * p.K * 4;
+#elif QUANT_K == 1
+    const uint a_panel_bytes = BM * p.K * 2;
+#else
+    const uint a_panel_bytes = (BM * p.K) / 2 + (BM * p.K) / 16;
+#endif
+    const uint group_m = clamp(GROUP_A_BUDGET / max(a_panel_bytes, 1u), 1u, min(blocks_m, 32u));
+    const uint tiles_per_group = group_m * blocks_n;
+    const uint lin = gl_WorkGroupID.y * blocks_m + (gl_WorkGroupID.x % blocks_m);
+    const uint group_id = lin / tiles_per_group;
+    const uint first_m = group_id * group_m;
+    const uint gsize = min(blocks_m - first_m, group_m);
+    const uint in_group = lin - group_id * tiles_per_group;
+    const uint ir = first_m + in_group % gsize;
+    const uint ic = in_group / gsize;
+#endif
+
 #ifdef MUL_MAT_ID
     load_row_ids(row_begin);
 #endif