# 12. Nulgrind: the minimal Valgrind tool

To use this tool, you must specify `--tool=none` on the Valgrind command line.

## 12.1. Overview

Nulgrind is the simplest possible Valgrind tool. It performs no instrumentation or analysis of a program, just runs it normally. It is mainly of use for Valgrind's developers for debugging and regression testing.

Nonetheless you can run programs with Nulgrind. They will run roughly 5 times more slowly than normal, for no useful effect. Note that you need to use the option `--tool=none` to run Nulgrind (ie. not `--tool=nulgrind`).