On Thu, 19 Jul 2018, Peter Zijlstra wrote: > On Tue, Jul 17, 2018 at 10:22:06PM -0400, Pavel Tatashin wrote: > > During boot tsc is calibrated twice: once in tsc_early_delay_calibrate(), > > and the second time in tsc_init(). > > > > Rename tsc_early_delay_calibrate() to tsc_early_init(), and rework it so > > the calibration is done only early, and make tsc_init() to use the values > > already determined in tsc_early_init(). > > > > Sometimes it is not possible to determine tsc early, as the subsystem that > > is required is not yet initialized, in such case try again later in > > tsc_init(). > > It might be nice to preserve some of the information tglx dug out during > review of all this. Like the various methods of calibrate_*() and their > dependencies. > > And I note that this patch relies on the magic of native_calibrate_cpu() > working really early and not exploding in the quick calibration run. > This either wants fixing or documenting. > > I think the initial idea was to only do the fast_calibrate (cpuid, msr > and possibly the quick_pit) things early and delay the HPET/PMTIMER > magic until later. Yes. I really would prefer to have this as an explicit expressed mechanism rather than relying on magic variables not being initialized. Thanks tglx -- To unsubscribe from this list: send the line "unsubscribe linux-s390" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
