Re: [suse-amd64] False "lost ticks" on dual-Opteron system (=> timer twice as fast)

[Ed Tomlinson <tomlins@cam.org>]

On Monday 09 May 2005 09:17, Bernd Paysan wrote:
> On Monday 09 May 2005 12:53, Bernd Paysan wrote:
> > On Sunday 08 May 2005 15:40, Andi Kleen wrote:
> > > Your system should be using the HPET timer to work exactly around
> > > this. AMD 8000 has HPET. Can you post a boot.log?
> >
> > Ok, boot.log attached. The only entry with hpet seems to indicate some
> > problems.
> 
> I went through the BIOS setup, and found a disabled feature "ACPI 2.0", 
> which I enabled. Now Linux finds the HPET timer.
> 
> # grep -i hpet boot.log 
> ACPI: HPET (v001 A M I  OEMHPET  0x04000518 MSFT 0x00000097) @ 
> 0x00000000e8ff3c30
> ACPI: HPET id: 0x102282a0 base: 0xfec01000
> time.c: Using 14.318180 MHz HPET timer.> 

> time.c: Using HPET based timekeeping.
> hpet0: at MMIO 0xfec01000, IRQs 2, 8, 0
> hpet0: 69ns tick, 3 32-bit timers
> hpet_acpi_add: no address or irqs in _CRS
> 
> and everything appears to work (though there's still no designated CPU to 
> handle the timer interrupts). xntpd syncs quickly, I'm happy (so far ;-).
> 
> So that explains why nobody sees this problem. But the TSC-based fallback 
> timekeeping is still broken on SMP systems with PowerNow and distributed 
> IRQ handling, which both together seem to be rare enough ;-).

Maybe on UP too:

May  8 18:50:25 grover kernel: [143640.507170] Attached scsi removable disk sda at scsi5, channel 0, id 0, lun 0
May  8 18:50:25 grover kernel: [143640.520422] rtc: lost some interrupts at 1024Hz.
May  8 18:50:25 grover kernel: [143640.554134] Attached scsi generic sg0 at scsi5, channel 0, id 0, lun 0,  type 0
May  8 18:50:25 grover kernel: [143640.567693] rtc: lost some interrupts at 1024Hz.
May  8 18:50:25 grover kernel: [143640.596402] usb-storage: device scan complete

This from 12-rc3-mm3, UP x86_64 with powernow active.  

It might be that the message is OK here since I do not see a fast clock.  I mention this
since powernow is active here.

Should HPET be available in UP?

Ed Tomlinson