From: Jeff Bolz <redacted>
Date: Tue, 1 Jul 2025 08:43:08 +0000 (-0500)
Subject: vulkan: Split large mul_mat_id to fit in shared memory (llama/14451)
X-Git-Tag: upstream/1.8.0~452
X-Git-Url: https://git.djapps.eu/?a=commitdiff_plain;h=3c7939cfe5c6432777ec287e38c50e65a1232dce;p=pkg%2Fggml%2Fsources%2Fwhisper.cpp

vulkan: Split large mul_mat_id to fit in shared memory (llama/14451)
---

diff --git a/ggml/src/ggml-vulkan/ggml-vulkan.cpp b/ggml/src/ggml-vulkan/ggml-vulkan.cpp
index fae7851a..09157bf5 100644
--- a/ggml/src/ggml-vulkan/ggml-vulkan.cpp
+++ b/ggml/src/ggml-vulkan/ggml-vulkan.cpp
@@ -6003,7 +6003,30 @@ static void ggml_vk_mul_mat_id(ggml_backend_vk_context * ctx, vk_context& subctx
     if (src2->ne[1] == 1 && (src0->type == GGML_TYPE_F32 || src0->type == GGML_TYPE_F16 || ggml_is_quantized(src0->type))) {
         ggml_vk_mul_mat_vec_id_q_f16(ctx, subctx, src0, src1, src2, dst, dryrun);
     } else {
-        ggml_vk_mul_mat_id_q_f16(ctx, subctx, src0, src1, src2, dst, dryrun);
+        // Split based on number of ids, to fit in shared memory
+        const uint32_t nei0 = (uint32_t)src2->ne[0];
+        const uint32_t nei1 = (uint32_t)src2->ne[1];
+
+        GGML_ASSERT(nei0 <= 4096);
+        const uint32_t split_size = std::min(nei1, 4096u / nei0);
+
+        ggml_tensor src1_copy = *src1;
+        ggml_tensor src2_copy = *src2;
+        ggml_tensor dst_copy = *dst;
+
+        for (uint32_t token_start = 0; token_start < nei1; token_start += split_size) {
+            const uint32_t n_tokens = std::min(split_size, nei1 - token_start);
+
+            src1_copy.view_offs = src1->view_offs + token_start * src1_copy.nb[2];
+            src2_copy.view_offs = src2->view_offs + token_start * src2_copy.nb[1];
+            dst_copy.view_offs = dst->view_offs + token_start * dst_copy.nb[2];
+
+            src1_copy.ne[2] = n_tokens;
+            src2_copy.ne[1] = n_tokens;
+            dst_copy.ne[2] = n_tokens;
+
+            ggml_vk_mul_mat_id_q_f16(ctx, subctx, src0, &src1_copy, &src2_copy, &dst_copy, dryrun);
+        }
     }
 }
 
@@ -10136,9 +10159,15 @@ static bool ggml_backend_vk_device_supports_op(ggml_backend_dev_t dev, const ggm
                 ggml_type src0_type = op->src[0]->type;
                 ggml_backend_vk_device_context * ctx = (ggml_backend_vk_device_context *)dev->context;
                 const vk_device& device = ggml_vk_get_device(ctx->device);
-                if (op->op == GGML_OP_MUL_MAT_ID && !device->mul_mat_id_s[src0_type] && !device->mul_mat_id_m[src0_type] && !device->mul_mat_id_l[src0_type]) {
-                    // If there's not enough shared memory for row_ids and the result tile, fallback to CPU
-                    return false;
+                if (op->op == GGML_OP_MUL_MAT_ID) {
+                    if (!device->mul_mat_id_s[src0_type] && !device->mul_mat_id_m[src0_type] && !device->mul_mat_id_l[src0_type]) {
+                        // If there's not enough shared memory for row_ids and the result tile, fallback to CPU
+                        return false;
+                    }
+                    // Check against size of shared memory variable
+                    if (op->src[2]->ne[0] > 4096) {
+                        return false;
+                    }
                 }
                 switch (src0_type) {
                     case GGML_TYPE_F32: