/* * Collect user-level profiling statistics; called on a profiling tick, * when a process is running in user-mode. This routine may be called * from an interrupt context. We try to update the user profiling buffers * cheaply with fuswintr() and suswintr(). If that fails, we revert to * an AST that will vector us to trap() with a context in which copyin * and copyout will work. Trap will then call addupc_task(). * * Note that we may (rarely) not get around to the AST soon enough, and * lose profile ticks when the next tick overwrites this one, but in this * case the system is overloaded and the profile is probably already * inaccurate. */