On Thu, Jul 19, 2018 at 6:49 AM Peter Zijlstra <pet...@infradead.org> wrote: > > On Tue, Jul 17, 2018 at 10:22:11PM -0400, Pavel Tatashin wrote: > > sched_clock_running may be read every time sched_clock_cpu() is called. > > Yet, this variable is updated only twice during boot, and never changes > > again, therefore it is better to make it a static key. > > Right, so the focus was always on making the sane TSC case fast, and if > TSC isn't stable we'd just make do and not care too much. >
True for CONFIG_HAVE_UNSTABLE_SCHED_CLOCK, but for other systems like SPARC, it hurts to have this variable accessed every time, even though they have a sane sched_clock(). > But this certainly isn't wrong, so ACK. Thank you, Pave