Re: [patch] Latency Tracer, voluntary-preempt-2.6.8-rc4-O6

Lee Revell
2004-08-13T07:39:52Z

On Thu, 2004-08-12 at 19:51, Ingo Molnar wrote:
> i've uploaded the latest version of the voluntary-preempt patch:
>
> http://redhat.com/~mingo/voluntary-preempt/voluntary-preempt-2.6.8-rc4-O6

Here's another weird one. This happens when you create a new tab in
gnome-terminal, which causes a fork().

preemption latency trace v1.0
-----------------------------
latency: 613 us, entries: 697 (697)
process: gnome-terminal/3467, uid: 1000
nice: 0, policy: 0, rt_priority: 0
=======>
0.000ms (+0.000ms): do_IRQ (common_interrupt)
0.000ms (+0.000ms): mask_and_ack_8259A (do_IRQ)
0.003ms (+0.003ms): generic_redirect_hardirq (do_IRQ)
0.004ms (+0.000ms): generic_handle_IRQ_event (do_IRQ)
0.004ms (+0.000ms): timer_interrupt (generic_handle_IRQ_event)
0.005ms (+0.000ms): mark_offset_tsc (timer_interrupt)
0.011ms (+0.006ms): do_timer (timer_interrupt)
0.011ms (+0.000ms): update_process_times (do_timer)
0.012ms (+0.000ms): update_one_process (update_process_times)
0.012ms (+0.000ms): run_local_timers (update_process_times)
0.012ms (+0.000ms): raise_softirq (update_process_times)
0.013ms (+0.000ms): scheduler_tick (update_process_times)
0.013ms (+0.000ms): sched_clock (scheduler_tick)
0.014ms (+0.001ms): task_timeslice (scheduler_tick)
0.015ms (+0.000ms): update_wall_time (do_timer)
0.015ms (+0.000ms): update_wall_time_one_tick (update_wall_time)
0.017ms (+0.001ms): generic_note_interrupt (do_IRQ)
0.017ms (+0.000ms): end_8259A_irq (do_IRQ)
0.017ms (+0.000ms): enable_8259A_irq (do_IRQ)
0.019ms (+0.001ms): do_softirq (do_IRQ)
0.019ms (+0.000ms): __do_softirq (do_softirq)
0.019ms (+0.000ms): wake_up_process (do_softirq)
0.020ms (+0.000ms): try_to_wake_up (wake_up_process)
0.020ms (+0.000ms): task_rq_lock (try_to_wake_up)
0.020ms (+0.000ms): activate_task (try_to_wake_up)
0.021ms (+0.000ms): sched_clock (activate_task)
0.021ms (+0.000ms): recalc_task_prio (activate_task)
0.022ms (+0.000ms): effective_prio (recalc_task_prio)
0.022ms (+0.000ms): enqueue_task (activate_task)
0.023ms (+0.000ms): preempt_schedule (try_to_wake_up)
0.024ms (+0.000ms): preempt_schedule (copy_page_range)
0.024ms (+0.000ms): preempt_schedule (copy_page_range)
0.025ms (+0.000ms): preempt_schedule (copy_page_range)
0.026ms (+0.000ms): preempt_schedule (copy_page_range)

...about 400+ of the same deleted...

0.459ms (+0.000ms): preempt_schedule (copy_page_range)
0.459ms (+0.000ms): preempt_schedule (copy_page_range)
0.460ms (+0.000ms): preempt_schedule (copy_page_range)
0.461ms (+0.000ms): preempt_schedule (copy_page_range)
0.461ms (+0.000ms): preempt_schedule (copy_page_range)
0.461ms (+0.000ms): check_preempt_timing (touch_preempt_timing)

Lee