Re: [patch] Real-Time Preemption, -RT-2.6.10-rc2-mm1-V0.7.27-3

[Florian Schmidt <mista.tapas@gmx.net>]

On Tue, 16 Nov 2004 23:42:57 +0100
Ingo Molnar <mingo@elte.hu> wrote:

> this is either a false positive, or we missed a preemption. To see which
> one, could you apply the attached patch and try to reproduce this long
> trace? The new trace will tell us whether need_resched is set during
> that ~1 msec window.

hmm, the output doens't look so much different (or am i just blind?). maybe
i need to do make clean before building with this patch applied?

flo


preemption latency trace v1.0.7 on 2.6.10-rc2-mm1-RT-V0.7.27-10
-------------------------------------------------------
 latency: 992 us, entries: 22 (22)   |   [VP:0 KP:1 SP:1 HP:1 #CPUS:1]
    -----------------
    | task: IRQ 0/2, uid:0 nice:0 policy:1 rt_prio:49
    -----------------
 => started at: try_to_wake_up+0x51/0x170 <c010f3a1>
 => ended at:   finish_task_switch+0x51/0xb0 <c010f911>
=======>
    5 80010004 0.000ms (+0.000ms): trace_start_sched_wakeup (try_to_wake_up)
    5 88010003 0.000ms (+0.000ms): (50) ((98))
    5 88010003 0.000ms (+0.000ms): (2) ((5))
    5 88010003 0.000ms (+0.000ms): try_to_wake_up (wake_up_process)
    5 88010003 0.000ms (+0.000ms): (0) ((1))
    5 88010002 0.000ms (+0.000ms): preempt_schedule (try_to_wake_up)
    5 88010002 0.000ms (+0.000ms): wake_up_process (redirect_hardirq)
    5 88010001 0.000ms (+0.000ms): preempt_schedule (__do_IRQ)
    5 88010001 0.000ms (+0.000ms): irq_exit (do_IRQ)
    5 88000002 0.000ms (+0.000ms): do_softirq (irq_exit)
    5 88000002 0.001ms (+0.990ms): __do_softirq (do_softirq)
    5 08000000 0.991ms (+0.000ms): preempt_schedule (_mmx_memcpy)
    5 98000000 0.991ms (+0.000ms): __schedule (preempt_schedule)
    5 98000000 0.991ms (+0.000ms): profile_hit (__schedule)
    5 98000001 0.991ms (+0.000ms): sched_clock (__schedule)
    2 80000002 0.991ms (+0.000ms): __switch_to (__schedule)
    2 80000002 0.991ms (+0.000ms): (5) ((2))
    2 80000002 0.992ms (+0.000ms): (98) ((50))
    2 80000002 0.992ms (+0.000ms): finish_task_switch (__schedule)
    2 80000001 0.992ms (+0.000ms): trace_stop_sched_switched (finish_task_switch)
    2 80000001 0.992ms (+0.001ms): (2) ((50))
    2 80000001 0.993ms (+0.000ms): trace_stop_sched_switched (finish_task_switch)