Scott Cheloha <[email protected]> writes:
> Hi, > > At the urging of sthen@ and dv@, here is v5. > > Two major changes from v4: > > - Add the function tc_reset_quality() to kern_tc.c and use it > to lower the quality of the TSC timecounter if we fail the > sync test. > > tc_reset_quality() will choose a new active timecounter if, > after the quality change, the given timecounter is no longer > the best timecounter. > > The upshot is: if you fail the TSC sync test you should boot > with the HPET as your active timecounter. If you don't have > an HPET you'll be using something else. > > - Drop the SMT accomodation from the hot loop. It hasn't been > necessary since last year when I rewrote the test to run without > a mutex. In the rewritten test, the two CPUs in the hot loop > are not competing for any resources so they should not be able > to starve one another. > > dv: Could you double-check that this still chooses the right > timecounter on your machine? If so, I will ask deraadt@ to > put this into snaps to replace v4. > Yes, looks like it's choosing acpihpet0 still with this diff. No issues after zzz/ZZZ either. $ sysctl | grep hpet kern.timecounter.hardware=acpihpet0 kern.timecounter.choice=i8254(0) tsc(-1000) acpihpet0(1000) acpitimer0(1000) I'm going to try getting the latest bios on this machine and see if anything changes. -dv
