On Wed, 2007-07-18 at 00:31 +0200, Alessandro Suardi wrote: > On 7/11/07, john stultz <[EMAIL PROTECTED]> wrote: > > On Wed, 2007-07-11 at 01:31 +0200, Alessandro Suardi wrote: > > > On 7/10/07, john stultz <[EMAIL PROTECTED]> wrote: > > > > On Tue, 2007-07-10 at 00:29 -0700, Andrew Morton wrote: > > > > > On Mon, 9 Jul 2007 16:27:59 +0200 "Alessandro Suardi" <[EMAIL > > > > > PROTECTED]> wrote: > > > > > > > > > > > My oldish AMD K7-800's clock began falling behind after > > > > > > rebooting from 2.6.20 (and 109 days uptime with a spotless > > > > > > clock) into 2.6.22; time lost is about four minutes each hour. > > > > > > > > > > > > Turns out that 2.6.22 marks my TSC as unstable and starts > > > > > > using PIT instead. Rebooting 2.6.22 with clocksource=tsc > > > > > > gets the original stable system time back. > > > > > > > > Alessandro, > > > > Can you send me dmesg output for 2.6.20 and 2.6.22 (without > > > > clocksource=tsc)? > > > > > > Actually, I lied a little bit - it was 2.6.22 with clock=tsc (which > > > warns on boot about clock= being deprecated in favor of > > > clocksource= ). I assume behavior is identical for now. > > > > > > Please find attached the dmesg ring (incomplete, as the > > > kernel ring size I have seems too small to hold the full > > > buffer, but it seems to have all the interesting stuff) of > > > 2.6.20, 2.6.22, 2.6.22 with clock=tsc. > > > > > > If you need more info, just ask. I'll be out of the country > > > from July 12 to the morning of July 16, and again from > > > July 17 to July 20, so if you'd rather get at this later on, > > > it's okay for me ;) > > > > You're dmesg output got chopped at the top. Please increase the kernel > > log buffer size. > > Done, please find attached both 2620 and 2622 full dmesg output, > with no clock= or clocksource= parameters. > > > Sounds like your PIT frequency is out of whack, and I'm guessing the > > generic clocksource watchdog blames the TSC and disqualifies it. > > > > Few things to check: > > 1) Make sure you're running the latest BIOS. > > I'm probably not, though I'm not sure I'd flash anything on such > an old machine - been running it since RedHat 9 with the > current BIOS. Plus, I removed the floppy drive to make room > for an extra IDE disk... it'd take me a little bit to find out whether > I still have the floppy drive around. > > > 2) See if booting w/ noapic changes anything > > Nope, 2622+noapic => PIT is still used and clock very quickly > lags behind. > > For the moment being I'll keep booting with clocksource=tsc. > Let me know whether you want me to test anything more...
Hmm. One other thing to check: If you boot 2.6.20 w/ clocksource=pit, is it consistent w/ 2.6.22 and same slow timekeeping issue shows up? thanks -john - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
