On Tue, Dec 3, 2024 at 6:15 PM Michal Koutný <mkoutny@xxxxxxxx> wrote: > > On Tue, Dec 03, 2024 at 11:01:41AM GMT, Michal Koutný <mkoutny@xxxxxxxx> wrote: > > On Fri, Nov 08, 2024 at 09:29:03PM GMT, Yafang Shao <laoar.shao@xxxxxxxxx> wrote: > > > sched_clock_irqtime may be disabled due to the clock source. When disabled, > > > irq_time_read() won't change over time, so there is nothing to account. We > > > can save iterating the whole hierarchy on every tick and context switch. > > > > > > Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx> > > > Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx> > > > --- > > > kernel/sched/psi.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > Reviewed-by: Michal Koutný <mkoutny@xxxxxxxx> > > On second thought, similar guard may be useful in psi_show() too. Since > there's a difference between zero pressure and unmeasured pressure (it'd > fail with EOPNOTSUPP). I'll update the psi_show() function in the next version. > > (How common is it actually that tsc_init fails?) This is not a common scenario, but it can occur randomly across a large fleet. -- Regards Yafang
