Re: amd64: calibrate lapic timer frequency in constant time

2020-09-01 Thread Scott Cheloha
On Tue, Sep 01, 2020 at 06:14:05PM +0200, Mark Kettenis wrote: > > Date: Tue, 1 Sep 2020 11:05:26 -0500 > > From: Scott Cheloha > > > > Hi, > > > > At boot, if we don't know the lapic frequency offhand we compute it by > > waiting for a known clock (the i8254) with a known frequency to cycle >

Re: amd64: calibrate lapic timer frequency in constant time

2020-09-01 Thread Mark Kettenis
> Date: Tue, 1 Sep 2020 11:05:26 -0500 > From: Scott Cheloha > > Hi, > > At boot, if we don't know the lapic frequency offhand we compute it by > waiting for a known clock (the i8254) with a known frequency to cycle > a few times. > > Currently we cycle hz times. This doesn't make sense.

amd64: calibrate lapic timer frequency in constant time

2020-09-01 Thread Scott Cheloha
Hi, At boot, if we don't know the lapic frequency offhand we compute it by waiting for a known clock (the i8254) with a known frequency to cycle a few times. Currently we cycle hz times. This doesn't make sense. There is little to no benefit to waiting additional cycles if your kernel is