On Mon, Aug 12, 2019 at 8:25 PM Thomas Gleixner <[email protected]> wrote: > > On Mon, 12 Aug 2019, Li, Aubrey wrote: > > On 2019/8/9 20:54, Thomas Gleixner wrote: > > > + local_irq_disable(); > > > /* > > > * Setup the APIC counter to maximum. There is no way the lapic > > > * can underflow in the 100ms detection time frame > > > */ > > > __setup_APIC_LVTT(0xffffffff, 0, 0); > > > > > > - /* Let the interrupts run */ > > > - local_irq_enable(); > > > + /* > > > + * Methods to terminate the calibration loop: > > > + * 1) Global clockevent if available (jiffies) > > > + * 2) TSC if available and frequency is known > > > + */ > > > + jif_start = READ_ONCE(jiffies); > > > + > > > + if (tsc_khz) { > > > + tsc_start = rdtsc(); > > > + tsc_perj = div_u64((u64)tsc_khz * 1000, HZ); > > > + } > > > + > > > + while (lapic_cal_loops <= LAPIC_CAL_LOOPS) { > > > > Is this loop still meaningful, can we just invoke the handler twice > > before and after the tick? > > And that solves what? >
I meant, can we do this one time? - lapic_cal_t1 = read APIC counter - /* Wait for a tick to elapse */ - lapic_cal_t2 = read APIC counter I'm not clear why we still need this loop, to use the existing lapic_cal_handler()? Thanks, -Aubrey
