On 12/13/2014 03:30 AM, Ingo Molnar wrote: >> > This is my no_hz related config: >> > >> > $ grep NO_HZ .config >> > CONFIG_NO_HZ_COMMON=y >> > # CONFIG_NO_HZ_IDLE is not set >> > CONFIG_NO_HZ_FULL=y >> > CONFIG_NO_HZ_FULL_ALL=y > Just curious, if you disable NO_HZ_FULL_ALL, does the bug change?
On 12/13/2014 07:08 AM, Paul E. McKenney wrote: > Alternatively, your could boot with nohz_full=2-27 (or maybe even > nohz_full=4-27). This will override CONFIG_NO_HZ_FULL_ALL=y and will > provide two (or four with 4-27) housekeeping CPUs that are available to > run things like RCU grace-period kthreads and RCU callback processing. > This might allow RCU to get the CPU bandwidth it needs despite > competition from your workload. I've tried both nohz_full=4-27 and disabling CONFIG_NO_HZ_FULL_ALL altogether, but I'm still seeing the stall: [ 725.670017] INFO: rcu_preempt detected stalls on CPUs/tasks: [ 725.670017] 0: (11 ticks this GP) idle=bbd/140000000000002/0 softirq=11529/11529 fqs=0 last_accelerate: 9d0e/a648, nonlazy_posted: 721357, .. [ 725.670017] (detected by 16, t=2102 jiffies, g=9857, c=9856, q=2581) [ 725.670017] Task dump for CPU 0: [ 725.670017] kworker/0:1 S ffff8800633abde8 13016 520 2 0x10080008 [ 725.670017] ffffffffb03027a8 ffff880a70f24017 ffffffffb043ef40 ffff88005ffea310 [ 725.670017] 0000000000000000 dfffe90000000000 0000000000000000 1ffffffff63bcdeb [ 725.670017] ffff88006be15030 ffffffffb1de6f58 ffffffffffffff10 ffffffffb0301237 [ 725.670017] Call Trace: [ 725.670017] [<ffffffffb03027a8>] ? retint_restore_args+0x13/0x13 [ 725.670017] [<ffffffffb0301237>] ? _raw_spin_unlock_irq+0x57/0x200 [ 725.670017] [<ffffffffb0301203>] ? _raw_spin_unlock_irq+0x23/0x200 [ 725.670017] [<ffffffffa04630cb>] ? worker_thread+0x15b/0x1680 [ 725.670017] [<ffffffffb02effef>] ? __schedule+0xf6f/0x2fc0 [ 725.670017] [<ffffffffa0462f70>] ? process_one_work+0x1650/0x1650 [ 725.670017] [<ffffffffa047ae12>] ? kthread+0x1f2/0x2b0 [ 725.670017] [<ffffffffa047ac20>] ? kthread_worker_fn+0x6a0/0x6a0 [ 725.670017] [<ffffffffb03018bc>] ? ret_from_fork+0x7c/0xb0 [ 725.670017] [<ffffffffa047ac20>] ? kthread_worker_fn+0x6a0/0x6a0 Thanks, Sasha -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
