What is the optimal way to measure the performance hit a change in the kernel brings to the system under normal conditions? Are there tools for this job or a standard procedure kernel developers follow or everyone comes up with his own metrics? I know it sounds vague and maybe the measurement must be related with where the change is on the kernel code. Say for example that I implemented some extra security checks in the copy_from_user function, or some other critical code. Whats the best way to measure the performance hit it causes? I have used measurements of the time a full kernel compile takes, but I dont think this is the best metric. Also, is there a test suite that somehow emulates actions of an average user or another for an average web server? So that you can take average measurements etc (In trying to establish an overall performance hit, so that the metric may be unrelated to the part of the kernel code that is affected)