train : move number of gpu layers argument parsing to common/train.cpp (ggml-org#4074)

- introduces help entry for the argument
 - cuts '--gpu-layers' form in order to simplify usage and documentation.

Signed-off-by: Jiri Podivin <jpodivin@gmail.com>
Co-authored-by: Jiri Podivin <jpodivin@redhat.com>

Author: jpodivin

common/train.cpp

@@ -1136,6 +1136,7 @@ void print_common_train_usage(int /*argc*/, char ** /*argv*/, const struct train
     fprintf(stderr, "  --adam-beta2 N             AdamW beta2 in interval [0,1). How much to smooth the second moment of gradients. (default %f)\n", params->adam_beta2);
     fprintf(stderr, "  --adam-gclip N             AdamW gradient clipping. Disabled when zero. (default %f)\n", params->adam_gclip);
     fprintf(stderr, "  --adam-epsf N              AdamW epsilon for convergence test. Disabled when <= zero. (default %f)\n", params->adam_eps_f);
+    fprintf(stderr, "  -ngl N, --n-gpu-layers N   Number of model layers to offload to GPU (default %d)", params->n_gpu_layers);
     fprintf(stderr, "\n");
 }
 
@@ -1355,6 +1356,17 @@ bool consume_common_train_arg(
             return true;
         }
         params->adam_gclip = std::stof(argv[i]);
+    } else if (arg == "-ngl" || arg == "--n-gpu-layers") {
+            if (++i >= argc) {
+                *invalid_param = true;
+                return true;
+            }
+#ifdef LLAMA_SUPPORTS_GPU_OFFLOAD
+            params->n_gpu_layers = std::stoi(argv[i]);
+#else
+            fprintf(stderr, "warning: not compiled with GPU offload support, --n-gpu-layers option will be ignored\n");
+            fprintf(stderr, "warning: see main README.md for information on enabling GPU BLAS support\n");
+#endif
     } else if (arg == "-h" || arg == "--help") {
         params->print_usage = true;
         return true;

examples/finetune/finetune.cpp

@@ -1460,17 +1460,6 @@ static bool train_params_parse(int argc, char ** argv, struct train_params * par
             }
             params->n_rank_w3 = std::stoi(argv[i]);
             params->custom_n_rank_w3 = true;
-        } else if (arg == "--gpu-layers" || arg == "-ngl" || arg == "--n-gpu-layers") {
-            if (++i >= argc) {
-                invalid_param = true;
-                break;
-            }
-#ifdef LLAMA_SUPPORTS_GPU_OFFLOAD
-            params->common.n_gpu_layers = std::stoi(argv[i]);
-#else
-            fprintf(stderr, "warning: not compiled with GPU offload support, --n-gpu-layers option will be ignored\n");
-            fprintf(stderr, "warning: see main README.md for information on enabling GPU BLAS support\n");
-#endif
         } else {
             fprintf(stderr, "error: unknown argument: %s\n", arg.c_str());
             train_print_usage(argc, argv, &default_params);