vulkan: Submit once enough matmul work has been recorded

ggml/src/ggml-vulkan/ggml-vulkan.cpp

@@ -8245,8 +8245,12 @@ static ggml_status ggml_backend_vk_graph_compute(ggml_backend_t backend, ggml_cg
     VK_LOG_DEBUG("ggml_backend_vk_graph_compute(" << cgraph->n_nodes << " nodes)");
     ggml_backend_vk_context * ctx = (ggml_backend_vk_context *)backend->context;
 
+    uint64_t total_mat_mul_bytes = 0;
     for (int i = 0; i < cgraph->n_nodes; i++) {
         ggml_vk_build_graph(ctx, cgraph->nodes[i], i, nullptr, 0, true, false, false);
+        if (cgraph->nodes[i]->op == GGML_OP_MUL_MAT || cgraph->nodes[i]->op == GGML_OP_MUL_MAT_ID) {
+            total_mat_mul_bytes += ggml_nbytes(cgraph->nodes[i]->src[0]);
+        }
     }
     if (ctx->device->need_compiles) {
         ggml_vk_load_shaders(ctx->device);
@@ -8267,17 +8271,27 @@ static ggml_status ggml_backend_vk_graph_compute(ggml_backend_t backend, ggml_cg
     bool first_node_in_batch = true; // true if next node will be first node in a batch
     int submit_node_idx = 0; // index to first node in a batch
 
-    // Submit work every nodes_per_submit nodes to overlap CPU cmdbuffer generation with GPU execution.
-    // Start with a smaller count to get work submitted right away, and increase it after each submit.
-    int nodes_per_submit = 20;
+    // Submit after enough work has accumulated, to overlap CPU cmdbuffer generation with GPU execution.
+    // Estimate the amount of matmul work by looking at the weight matrix size, and submit every 100MB
+    // (and scaled down based on model size, so smaller models submit earlier).
+    // Also submit at least every 100 nodes, in case there are workloads without as much matmul.
+    int nodes_per_submit = 100;
     int submitted_nodes = 0;
     int submit_count = 0;
+    uint64_t mul_mat_bytes = 0;
+    uint64_t mul_mat_bytes_per_submit = std::min(uint64_t(100*1000*1000), total_mat_mul_bytes / 40u);
     for (int i = 0; i < cgraph->n_nodes; i++) {
         if (first_node_in_batch) {
             submit_node_idx = i;
         }
 
-        bool submit = (submitted_nodes >= nodes_per_submit) || (i == last_node);
+        if (cgraph->nodes[i]->op == GGML_OP_MUL_MAT || cgraph->nodes[i]->op == GGML_OP_MUL_MAT_ID) {
+            mul_mat_bytes += ggml_nbytes(cgraph->nodes[i]->src[0]);
+        }
+
+        bool submit = (submitted_nodes >= nodes_per_submit) ||
+                      (mul_mat_bytes >= mul_mat_bytes_per_submit) ||
+                      (i == last_node);
 
         bool enqueued = ggml_vk_build_graph(ctx, cgraph->nodes[i], i, cgraph->nodes[submit_node_idx], submit_node_idx, false, i == last_node, submit);
 
@@ -8294,13 +8308,9 @@ static ggml_status ggml_backend_vk_graph_compute(ggml_backend_t backend, ggml_cg
         if (submit) {
             first_node_in_batch = true;
             submitted_nodes = 0;
-            switch (submit_count) {
-            case 0:
-                nodes_per_submit = 50;
-                break;
-            default:
-                nodes_per_submit = 100;
-                break;
+            mul_mat_bytes = 0;
+            if (submit_count < 3) {
+                mul_mat_bytes_per_submit *= 2;
             }
             submit_count++;
         }