1.6ms jitter in rtc_wakeup (Re: 2.6.14-rc4-rt1)

From: Esben Nielsen (simlo_at_phys.au.dk)
Date: 10/13/05

  • Next message: Qukasz_Gromanowski?=: "Newbie problem with Gigabyte GA-K8U mainboard, ALi/ULi 1689 chipset and agpgart..." 
    Date:	Thu, 13 Oct 2005 23:14:46 +0200 (METDST)
To: Ingo Molnar <mingo@elte.hu>

    On Tue, 11 Oct 2005, Ingo Molnar wrote:

    >
    > i have released the 2.6.14-rc4-rt1 tree, which can be downloaded from
    > the usual place:
    >
    > http://redhat.com/~mingo/realtime-preempt/
    >

    I set up rtc_wakeup and got a jitter up 1.6ms!
    It came when I cd'en into a nfs-mount and typed ls.

    Output from rtc_wakeup:
    ...
    new max. jitter: 19.9% (48 usec)
    threshold violated: 25.5% (62usec)
    new max. jitter: 25.5% (62 usec)
    threshold violated: 684.9% (1672usec)
    new max. jitter: 684.9% (1672 usec)
    threshold violated: 85.2% (207usec)
    done.
    total # of irqs: 3440126
    missed irqs: 0
    threshold violations: 3
    max jitter: 684.9% (1672 usec)
     
    /proc/latency_trace:
    preemption latency trace v1.1.5 on 2.6.14-rc4-rt1
    --------------------------------------------------------------------
     latency: 1595 us, #20/20, CPU#0 | (M:rt VP:0, KP:0, SP:1 HP:1)
        -----------------
        | task: IRQ 8-775 (uid:0 nice:-5 policy:1 rt_prio:99)
        -----------------

                     _------=> CPU#
                    / _-----=> irqs-off
                   | / _----=> need-resched
                   || / _---=> hardirq/softirq
                   ||| / _--=> preempt-depth
                   |||| /
                   ||||| delay
       cmd pid ||||| time | caller
          \ / ||||| \ | /
          ls-11239 0D.h3 0us : __trace_start_sched_wakeup (try_to_wake_up)
          ls-11239 0D.h3 0us : __trace_start_sched_wakeup <IRQ 8-775> (0 0)
          ls-11239 0Dnh2 1us : try_to_wake_up <IRQ 8-775> (0 75)
          ls-11239 0Dnh1 1us : preempt_schedule (try_to_wake_up)
          ls-11239 0Dnh1 2us : wake_up_process (redirect_hardirq)
          ls-11239 0Dnh. 2us : preempt_schedule (__do_IRQ)
          ls-11239 0Dnh. 3us : irq_exit (do_IRQ)
          ls-11239 0Dn.. 3us : preempt_schedule_irq (need_resched)
          ls-11239 0Dn.. 3us : __schedule (preempt_schedule_irq)
          ls-11239 0Dn.. 4us : profile_hit (__schedule)
          ls-11239 0Dn.1 4us : sched_clock (__schedule)
          ls-11239 0Dn.1 5us : check_tsc_unstable (sched_clock)
          ls-11239 0Dn.1 5us : tsc_read_c3_time (sched_clock)
       IRQ 8-775 0D..2 6us : __switch_to (__schedule)
       IRQ 8-775 0D..2 7us!: __schedule <ls-11239> (75 0)
       IRQ 8-775 0...1 1594us : trace_stop_sched_switched (__schedule)
       IRQ 8-775 0D..2 1594us : trace_stop_sched_switched <IRQ 8-775> (0 0)
       IRQ 8-775 0D..2 1595us : trace_stop_sched_switched (__schedule)

    Esben

    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    • TEXT/PLAIN attachment: config
  • Next message: Qukasz_Gromanowski?=: "Newbie problem with Gigabyte GA-K8U mainboard, ALi/ULi 1689 chipset and agpgart..."

    Relevant Pages