On Mon, Feb 16, 2009 at 02:21:51PM +0100, Ingo Molnar wrote: > > * Damien Wyart <damien.wyart@xxxxxxx> wrote: > > > * Ingo Molnar <mingo@xxxxxxx> [090216 13:26]: > > > We do get 0x100 which is 1 << RCU_SOFTIRQ, i.e. the RCU softirq. Paul, > > > this indeed seems to be a CONFIG_TREE_RCU=y bug. > > > > > What is weird is that RCU_SOFTIRQ gets set again and again - but there's > > > no raise_softirq() calls. Could you please do a two-CPU trace too via: > > > > > echo 3 > /debug/tracing/tracing_cpumask > > > > > So that we can see what's happening on the other CPU? > > > > > Also, could you please apply the debug patch below (or update to the > > > very latest -tip tree), so that we get trace entries of softirq triggers > > > too? > > > > Ok, the new trace with these additional modifications is here: > > http://damien.wyart.free.fr/ksoftirqd_pb/trace_tip_2009.02.16_1300_ksoftirqd_pb_abstime_proc_mask3.txt.gz > > thanks. > > This confirms that SOFTIRQ_RCU gets raised here in the timer IRQ: > > 136.255963 | 0) sleep-2345 | | update_process_times() { > 136.255964 | 0) sleep-2345 | | account_process_tick() { > 136.255965 | 0) sleep-2345 | 0.779 us | account_system_time(); > 136.255966 | 0) sleep-2345 | 2.262 us | } > 136.255967 | 0) sleep-2345 | | run_local_timers() { > 136.255968 | 0) sleep-2345 | 0.802 us | hrtimer_run_queues(); > 136.255969 | 0) sleep-2345 | | raise_softirq() { > 136.255970 | 0) sleep-2345 | | raise_softirq_irqoff() { > 136.255971 | 0) sleep-2345 | | __raise_softirq_irqoff() { > 136.255972 | 0) sleep-2345 | | /* nr: 1 */ > 136.255973 | 0) sleep-2345 | 2.194 us | } > 136.255974 | 0) sleep-2345 | 3.832 us | } > 136.255975 | 0) sleep-2345 | 5.491 us | } > 136.255976 | 0) sleep-2345 | 8.667 us | } > 136.255976 | 0) sleep-2345 | 0.792 us | rcu_pending(); > 136.255978 | 0) sleep-2345 | | rcu_check_callbacks() { > 136.255979 | 0) sleep-2345 | 0.781 us | idle_cpu(); > 136.255981 | 0) sleep-2345 | | raise_softirq() { > 136.255981 | 0) sleep-2345 | | raise_softirq_irqoff() { > 136.255982 | 0) sleep-2345 | | __raise_softirq_irqoff() { > 136.255983 | 0) sleep-2345 | | /* nr: 8 */ > 136.255984 | 0) sleep-2345 | 1.555 us | } > 136.255984 | 0) sleep-2345 | 3.059 us | } > 136.255985 | 0) sleep-2345 | 4.594 us | } > 136.255986 | 0) sleep-2345 | 7.800 us | } > 136.255987 | 0) sleep-2345 | 0.737 us | printk_tick(); > > again and again. Interesting... I will take a look! Thanx, Paul -- To unsubscribe from this list: send the line "unsubscribe kernel-testers" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
