llama-bench : pad the context to 256

Author: ggerganov

tools/llama-bench/llama-bench.cpp

@@ -1124,7 +1124,7 @@ struct cmd_params_instance {
     llama_context_params to_llama_cparams() const {
         llama_context_params cparams = llama_context_default_params();
 
-        cparams.n_ctx           = n_prompt + n_gen + n_depth;
+        cparams.n_ctx           = GGML_PAD(n_prompt + n_gen + n_depth, 256);
         cparams.n_batch         = n_batch;
         cparams.n_ubatch        = n_ubatch;
         cparams.type_k          = type_k;