Re: 24 lost ticks with 2.6.20.10 kernel

Michel Lespinasse wrote:

I'm having an issue with lost ticks, runnign linux 2.6.20.10 on an
intel DQ965GF motherboard. For some reason this occurs with clock-like
regularity, always exactly 24 lost ticks, about every two seconds.
This is running with 250-HZ ticks, and the small pause every two seconds
is also noticeable when using the console.


running with report_lost_ticks, I see the following:

May 1 12:58:57 server kernel: time.c: Lost 24 timer tick(s)! rip _spin_unlock_irqrestore+0x8/0x9)
May 1 12:58:59 server kernel: time.c: Lost 24 timer tick(s)! rip _spin_unlock_irqrestore+0x8/0x9)
May 1 12:59:01 server kernel: time.c: Lost 25 timer tick(s)! rip _spin_unlock_irqrestore+0x8/0x9)
May 1 12:59:03 server kernel: time.c: Lost 24 timer tick(s)! rip _spin_unlock_irqrestore+0x8/0x9)
May 1 12:59:07 server last message repeated 2 times
May 1 12:59:10 server kernel: time.c: Lost 24 timer tick(s)! rip handle_IRQ_event+0x19/0x55)
May 1 12:59:12 server kernel: time.c: Lost 24 timer tick(s)! rip handle_IRQ_event+0x19/0x55)
May 1 12:59:14 server kernel: time.c: Lost 24 timer tick(s)! rip _spin_unlock_irqrestore+0x8/0x9)
May 1 12:59:16 server kernel: time.c: Lost 24 timer tick(s)! rip _spin_unlock_irqrestore+0x8/0x9)
May 1 12:59:18 server kernel: time.c: Lost 24 timer tick(s)! rip handle_IRQ_event+0x19/0x55)
May 1 12:59:20 server kernel: time.c: Lost 24 timer tick(s)! rip _spin_unlock_irqrestore+0x8/0x9)
May 1 12:59:52 server last message repeated 15 times
May 1 13:00:51 server last message repeated 28 times
May 1 13:01:47 server last message repeated 27 times
May 1 13:01:50 server kernel: time.c: Lost 25 timer tick(s)! rip _spin_unlock_irqrestore+0x8/0x9)
May 1 13:01:56 server last message repeated 3 times
May 1 13:01:58 server kernel: time.c: Lost 24 timer tick(s)! rip _spin_unlock_irqrestore+0x8/0x9)


Since the rip often mentions _spin_unlock_irqrestore, I figured maybe
someone sleeps for 25 ticks with the interrupts disabled. I tried
running with CONFIG_DEBUG_SPINLOCK_SLEEP but this did not uncover anything.


I also noticed this code in arch/x86_64/kernel/time.c. I'm not sure if it
has anything to do with my issue, but it might since I get lost_count==24...
I could not figure out what this code is trying to do though.

#ifdef CONFIG_CPU_FREQ
/* In some cases the CPU can change frequency without us noticing
Give cpufreq a change to catch up. */
if ((lost_count+1) % 25 == 0)
cpufreq_delayed_get();
#endif


I'm not sure where to go from here. Additional information about my system:


Try disabling CONFIG_CPU_FREQ?


One last thing: I have another box which is fairly similar, with a
DG965RY motherboard. That other box does *not* seem to lose any ticks,
running the same kernel that works so poorly on the DQ965GF board.
Does that point to a hardware/bios issue then ?????

Is it running the exact same kernel, with the same cpufreq settings at
runtime (governor, controller, etc?)
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

Relevant Pages

  • RE: SBS SP! - last part wont install
    ... No it ids not a Dell Server. ... 13.188: Destination: ... 13.360: AnalyzePhaseZero used 0 ticks ... 13.625: AnalyzeComponents: Hotpatch analysis disabled; ...
    (microsoft.public.windows.server.sbs)
  • Re: A variant of the DateTime data type needed in VB.NET
    ... > A datetime is actual a value that contains ticks from a certain start date ... > (which differs by instance when it is from a server or is internally). ... A datetime is actually a value that contains "100-nanosecond units called ...
    (microsoft.public.dotnet.languages.vb)
  • Re: A variant of the DateTime data type needed in VB.NET
    ... A datetime is actual a value that contains ticks from a certain start date ... (which differs by instance when it is from a server or is internally). ...
    (microsoft.public.dotnet.languages.vb)
  • Configuration Error ->error loading xml web.conf Parameter name: ticks.
    ... Parser Error Message: Error loading XML file E:\Inetpub\wwwroot\web.config ... Ticks must be between DateTime.MinValue.Ticks and DateTime.MaxValue.Ticks. ... windows 2000 server ...
    (microsoft.public.dotnet.framework.aspnet)
  • Re: [RFC][PATCH 4/6] Fix (bad?) interactions between SCHED_RT and SCHED_NORMAL tasks
    ... lrq was inactive for several ticks, then its exec_delta will be seen as ... zero for those several ticks, which means we would compute its 'this_load' to be ... per-group 'load balancing' so refrain from further commenting so ... Even though this lost ticks loop is easily triggered with user-based lrqs, ...
    (Linux-Kernel)