On Wed, Jun 19, 2019 at 10:02 PM Arnd Bergmann <[email protected]> wrote: > > get_jiffies_boot_64 26 > > ktime_get_coarse_boottime 26 > > ktime_get_boot_fast_ns with tsc 70 > > ktime_get_boot_fast_ns with hpet 4922 > > ktime_get_boot_fast_ns with acpi_pm 1884 > > > > As expected, hpet is really quite painful. > > I would prefer not to add the new interface then. We might in > fact move users of get_jiffies_64() to ktime_get_coarse() for > consistency given the small overhead of that function.
In light of the measurements, that seems like a good plan to me. One thing to consider with moving jiffies users over that way is ktime_t. Do you want to introduce helpers like ktime_get_boot_coarse_ns(), just like there is already with the other various functions like ktime_get_boot_ns(), ktime_get_boot_fast_ns(), etc? (I'd personally prefer using the _ns variants, at least.) I can send a patch for this. Jason
