On Tue, Dec 08 2020 at 09:33, Andy Lutomirski wrote: > On Tue, Dec 8, 2020 at 8:26 AM Maxim Levitsky <mlevitsk@xxxxxxxxxx> wrote: > > IIRC we introduced mul_u64_u32_shift() for roughly this reason,but we > don't seem to be using it in the relevant code paths. We should be > able to use the same basic math with wider intermediates to allow very > large intervals between updates. That's 128 bit math and _NO_ we are not going there for various reasons. Hint1: There is a world outside of x8664 and TSC. Hint2: Even on x8664 and TSC it comes with performance overhead Thanks, tglx