Patrick Welche <pr...@cam.ac.uk> writes: > On Tue, Jun 18, 2019 at 04:56:33PM -0000, Michael van Elst wrote: >> g...@lexort.com (Greg Troxel) writes: >> >> > -timecounter: Timecounter "ACPI-Safe" frequency 3579545 Hz quality 900 >> > +timecounter: Timecounter "ACPI-Fast" frequency 3579545 Hz quality 1000 >> >> > -timecounter: Timecounter "TSC" frequency 2800071320 Hz quality 3000 >> > +timecounter: Timecounter "TSC" frequency 3920113160 Hz quality 3000 >> >> That looks like a non-invariant TSC that changes with the "turbo" mode >> of the CPU. The interesting part is the 3.9GHz number, according to Intel >> your CPU can only go up to 3.06GHz.
estd -f reports: 1600 MHz 1733 MHz 1867 MHz 2000 MHz 2133 MHz 2267 MHz 2400 MHz 2533 MHz 2667 MHz 2800 MHz 2801 MHz and dmesg shows acpicpu0 at cpu0: ACPI CPU acpicpu0: C1: FFH, lat 1 us, pow 1000 mW acpicpu0: C2: FFH, lat 17 us, pow 500 mW acpicpu0: C3: FFH, lat 17 us, pow 350 mW acpicpu0: P0: FFH, lat 10 us, pow 143000 mW, 2801 MHz, turbo boost acpicpu0: P1: FFH, lat 10 us, pow 130000 mW, 2800 MHz acpicpu0: P2: FFH, lat 10 us, pow 114000 mW, 2667 MHz acpicpu0: P3: FFH, lat 10 us, pow 100000 mW, 2533 MHz acpicpu0: P4: FFH, lat 10 us, pow 87000 mW, 2400 MHz acpicpu0: P5: FFH, lat 10 us, pow 76000 mW, 2267 MHz acpicpu0: P6: FFH, lat 10 us, pow 68000 mW, 2133 MHz acpicpu0: P7: FFH, lat 10 us, pow 59000 mW, 2000 MHz acpicpu0: P8: FFH, lat 10 us, pow 51000 mW, 1867 MHz acpicpu0: P9: FFH, lat 10 us, pow 44000 mW, 1733 MHz acpicpu0: P10: FFH, lat 10 us, pow 40000 mW, 1600 MHz acpicpu0: T0: FFH, lat 1 us, pow 1040 mW, 100 % acpicpu0: T1: FFH, lat 1 us, pow 910 mW, 88 % acpicpu0: T2: FFH, lat 1 us, pow 780 mW, 75 % acpicpu0: T3: FFH, lat 1 us, pow 650 mW, 63 % acpicpu0: T4: FFH, lat 1 us, pow 520 mW, 50 % acpicpu0: T5: FFH, lat 1 us, pow 390 mW, 38 % acpicpu0: T6: FFH, lat 1 us, pow 260 mW, 25 % acpicpu0: T7: FFH, lat 1 us, pow 130 mW, 13 % >> >I then set: >> > kern.timecounter.hardware = hpet0 >> >and things seem ok, at least after 10 minutes. >> >> That's what to do, you can also use the ACPI timer. Thanks. Interestingly, I am seeing different a ntp.drift value for hpet vs former tsc, but that's not really surprising. > I just hit the same very incorrect time on my everyday laptop which had > no issues (other than SNA artifacts ;-) ) Something must have changed... The kernel that was ok was built (which very likely means I did a cvs update just before): Wed May 15 01:30:14 EDT 2019 The kernel exhibiting the bad TSC was built Mon Jun 3 17:19:36 EDT 2019 which if accurate gives us a small window for bisecting. I will try the older kernel, and then see if I can search. I wonder if somehow with different code the cpu/tsc is being configured so that tsc doesn't do what it used to. Is anyone else seeing this problem?
