On Tue, 22 Oct 2019, Huacai Chen wrote: https://people.kernel.org/tglx/notes-about-netiquette Look for Toppost > If we use (s64)cycles < 0, then how to solve the problem that a 64bit > counter become negative? I doubt that you will be able to observe that. A 64bit value becomes negative after 1<<63 cycles, i.e. at 1GHz thats 292 years of uptime. What's your problem? Thanks, tglx