On Mon, Sep 19, 2016 at 09:58:39PM -0700, Kees Cook wrote: > Hi, > > Al had asked me a couple weeks back what the ratio of const vs dynamic > usercopying was. With Josh's cleanup and my fix-up to only call the > hardened usercopy when non-const, I can actually gather these statistics > on a build. It's a bit of a hack (see attached patch that should not go > into the tree), but with my not-very-defconfig, it's rougly 2 to 1 const > vs dynamic. However, this doesn't take into account the frequency at > _runtime_, which maybe could be discovered via perf comparing copy*user() > calls to __check_object_size() calls, but I didn't try that. Does someone > have perf setup to check this?
Maybe do something like this with your patch? trace-cmd record -p function -l __check_object_size -l __skip_check_object_size [command you want to benchmark] trace-cmd report -- Josh
