[2.4.16] Clock locking bugs?

[2.4.16] Clock locking bugs?

[Simon Kirby]

Just had a server's clock stop at 9:02:30am.  Very interesting
results:

[sroot@pro:/]# cat /proc/interrupts
           CPU0       CPU1       
  0:  172839353  172896882    IO-APIC-edge  timer
  1:        578        522    IO-APIC-edge  keyboard
  2:          0          0          XT-PIC  cascade
  4:      22002      21840    IO-APIC-edge  serial
 10:  581309135  580556518   IO-APIC-level  eth0
 12:   63077142   63023533   IO-APIC-level  aic7xxx
NMI:          0          0 
LOC:  345979794  345980089 
ERR:          0
MIS:          0

...

[sroot@pro:/]# cat /proc/interrupts
           CPU0       CPU1       
  0:  172839353  172896882    IO-APIC-edge  timer
  1:        578        522    IO-APIC-edge  keyboard
  2:          0          0          XT-PIC  cascade
  4:      22002      21840    IO-APIC-edge  serial
 10:  581309219  580556518   IO-APIC-level  eth0
 12:   63077142   63023533   IO-APIC-level  aic7xxx
NMI:          0          0 
LOC:  345979883  345980178 
ERR:          0
MIS:          0

Alan says this is due to locking problems with the timer I/O code. 

On the console were a lot of "set_rtc_mmss: can't update from 79 to 32"
type messages that have always happened on SMP kernels with ntpd.

Has anybody created any patches for this?

Simon-

[  Stormix Technologies Inc.  ][  NetNation Communications Inc. ]
[       sim@stormix.com       ][       sim@netnation.com        ]
[ Opinions expressed are not necessarily those of my employers. ]

Re: [2.4.16] Clock locking bugs?

[Simon Kirby]

Hrm...Just had this happen on my dual celeron desktop, exactly the same
problem.  Kernel 2.5.7.  Everything I typed in an rxvt was one character
lagged. :)

Simon-

On Mon, Jan 14, 2002 at 10:02:15AM -0800, Simon Kirby wrote:

> Just had a server's clock stop at 9:02:30am.  Very interesting
> results:
> 
> [sroot@pro:/]# cat /proc/interrupts
>            CPU0       CPU1       
>   0:  172839353  172896882    IO-APIC-edge  timer
>   1:        578        522    IO-APIC-edge  keyboard
>   2:          0          0          XT-PIC  cascade
>   4:      22002      21840    IO-APIC-edge  serial
>  10:  581309135  580556518   IO-APIC-level  eth0
>  12:   63077142   63023533   IO-APIC-level  aic7xxx
> NMI:          0          0 
> LOC:  345979794  345980089 
> ERR:          0
> MIS:          0
> 
> ...
> 
> [sroot@pro:/]# cat /proc/interrupts
>            CPU0       CPU1       
>   0:  172839353  172896882    IO-APIC-edge  timer
>   1:        578        522    IO-APIC-edge  keyboard
>   2:          0          0          XT-PIC  cascade
>   4:      22002      21840    IO-APIC-edge  serial
>  10:  581309219  580556518   IO-APIC-level  eth0
>  12:   63077142   63023533   IO-APIC-level  aic7xxx
> NMI:          0          0 
> LOC:  345979883  345980178 
> ERR:          0
> MIS:          0
> 
> Alan says this is due to locking problems with the timer I/O code. 
> 
> On the console were a lot of "set_rtc_mmss: can't update from 79 to 32"
> type messages that have always happened on SMP kernels with ntpd.
> 
> Has anybody created any patches for this?
> 
> Simon-
> 
> [  Stormix Technologies Inc.  ][  NetNation Communications Inc. ]
> [       sim@stormix.com       ][       sim@netnation.com        ]
> [ Opinions expressed are not necessarily those of my employers. ]

Re: [2.4.16] Clock locking bugs?

[Paul Gortmaker]

You've just given another example of why set_rtc_mmss should die (or at a 
minimum, not be enabled by default) - the timer died, and it wants to push 
its incorrect time onto the rtc as well.  I've posted patches to this effect 
several times before; now that we are into 2.5, I'll push them again...

I doubt that such a change would influence your timer problem, but feel 
free to #if 0  out the set_rtc_mmss routine, and the cruft that calls
it from the timer interrupt - i.e. if (time_status & STA_UNSYNC) 
in arch/i386/kernel/time.c  - you can then make the *policy* decision
in userspace as to whether you want to sync the rtc with the kernel time.

[At a minimum, I guarantee the annoying set_rtc_mmss messages go away :) ]

Paul.

Simon Kirby wrote:
> 
> Hrm...Just had this happen on my dual celeron desktop, exactly the same
> problem.  Kernel 2.5.7.  Everything I typed in an rxvt was one character
> lagged. :)
> 
> Simon-
> 
> On Mon, Jan 14, 2002 at 10:02:15AM -0800, Simon Kirby wrote:
> 
> > Just had a server's clock stop at 9:02:30am.  Very interesting
> > results:
> >
> > [sroot@pro:/]# cat /proc/interrupts
> >            CPU0       CPU1
> >   0:  172839353  172896882    IO-APIC-edge  timer
...
> > [sroot@pro:/]# cat /proc/interrupts
> >            CPU0       CPU1
> >   0:  172839353  172896882    IO-APIC-edge  timer
> >
> > Alan says this is due to locking problems with the timer I/O code.
> >
> > On the console were a lot of "set_rtc_mmss: can't update from 79 to 32"
> > type messages that have always happened on SMP kernels with ntpd.
> >
> > Has anybody created any patches for this?