Updating the usage help text

Author: tlemo

tests/test-backend-ops.cpp

@@ -5991,13 +5991,14 @@ static bool test_backend(ggml_backend_t backend, test_mode mode, const char * op
 }
 
 static void usage(char ** argv) {
-    printf("Usage: %s [mode] [-o <op>] [-b <backend>] [-p <params regex>] [--output <console|sql|csv>]\n", argv[0]);
+    printf("Usage: %s [mode] [-o <op,..>] [-b <backend>] [-p <params regex>] [--output <console|sql|csv>]\n", argv[0]);
     printf("    valid modes:\n");
     printf("      - test (default, compare with CPU backend for correctness)\n");
     printf("      - grad (compare gradients from backpropagation with method of finite differences)\n");
     printf("      - perf (performance evaluation)\n");
     printf("      - support (probe backend operation support)\n");
-    printf("    op names for -o are as given by ggml_op_desc() (e.g. ADD, MUL_MAT, etc)\n");
+    printf("    op names for -o are as given by ggml_op_desc() (e.g. ADD, MUL_MAT, etc),\n");
+    printf("        optionally including the full test case string (e.g. \"ADD(type=f16,ne=[1,1,8,1],nr=[1,1,1,1],nf=1)\")\n");
     printf("    --output specifies output format (default: console, options: console, sql, csv)\n");
 }