On Tue, 2013-01-08 at 17:26 -0500, Rik van Riel wrote:
> Please let me know if you manage to break this code in any way,
> so I can fix it...
I didn't break it, but did let it play with rq->lock contention. Using
cyclictest -Smp99 -i 100 -d 0, with 3 rt tasks for pull_rt_task() to
pull around appears to have been a ~dead heat.
3.6.11 3.6.11-spinlock
PerfTop: 78852 irqs/sec kernel:96.4% exact: 0.0% [1000Hz cycles],
(all, 80 CPUs)
-------------------------------------------------------------------------------------------------
samples pcnt function samples pcnt function
_______ _____ ___________________________ _______ _____
___________________________
468341.00 52.0% cpupri_set 471786.00 52.0%
cpupri_set
110259.00 12.2% _raw_spin_lock 88963.00 9.8%
ticket_spin_lock_wait
78863.00 8.8% native_write_msr_safe 77109.00 8.5%
native_write_msr_safe
42882.00 4.8% __schedule 48858.00 5.4%
native_write_cr0
40930.00 4.5% native_write_cr0 47038.00 5.2%
__schedule
13718.00 1.5% finish_task_switch 24775.00 2.7%
_raw_spin_lock
13188.00 1.5% plist_del 13117.00 1.4% plist_del
13078.00 1.5% _raw_spin_lock_irqsave 12372.00 1.4%
ttwu_do_wakeup
12083.00 1.3% ttwu_do_wakeup 11553.00 1.3%
_raw_spin_lock_irqsave
8359.00 0.9% pull_rt_task 8186.00 0.9%
pull_rt_task
6979.00 0.8% apic_timer_interrupt 7989.00 0.9%
finish_task_switch
4623.00 0.5% __enqueue_rt_entity 6430.00 0.7%
apic_timer_interrupt
3961.00 0.4% resched_task 4721.00 0.5%
resched_task
3942.00 0.4% __switch_to 4109.00 0.5%
__switch_to
3128.00 0.3% _raw_spin_trylock 2917.00 0.3%
rcu_idle_exit_common
3081.00 0.3% __tick_nohz_idle_enter 2897.00 0.3%
__local_bh_enable
2561.00 0.3% update_curr_rt 2873.00 0.3%
_raw_spin_trylock
2385.00 0.3% _raw_spin_lock_irq 2674.00 0.3%
__enqueue_rt_entity
2190.00 0.2% __local_bh_enable 2434.00 0.3%
update_curr_rt
1904.00 0.2% rcu_idle_exit_common 2161.00 0.2%
hrtimer_interrupt
1870.00 0.2% clockevents_program_event 2106.00 0.2%
ktime_get_update_offsets
1828.00 0.2% hrtimer_interrupt 1766.00 0.2%
tick_nohz_idle_exit
1741.00 0.2% do_nanosleep 1608.00 0.2%
__tick_nohz_idle_enter
1681.00 0.2% sys_clock_nanosleep 1437.00 0.2%
do_nanosleep
1639.00 0.2% pick_next_task_rt 1428.00 0.2%
hrtimer_init
1630.00 0.2% pick_next_task_stop 1320.00 0.1%
sched_clock_idle_sleep_event
1535.00 0.2% _raw_spin_unlock_irqrestore 1290.00 0.1%
sys_clock_nanosleep
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