the initial parsing is fine... Aug 01 14:05:51 aws-dublin kernel: rcu: Hierarchical RCU implementation. Aug 01 14:05:51 aws-dublin kernel: rcu: RCU restricting CPUs from NR_CPUS=128 to nr_cpu_ids=4. Aug 01 14:05:51 aws-dublin kernel: Rude variant of Tasks RCU enabled. Aug 01 14:05:51 aws-dublin kernel: Tracing variant of Tasks RCU enabled. Aug 01 14:05:51 aws-dublin kernel: rcu: RCU calculated value of scheduler-enlistment delay is 10 jiffies. Aug 01 14:05:51 aws-dublin kernel: rcu: Adjusting geometry for rcu_fanout_leaf=16, nr_cpu_ids=4 Aug 01 14:05:51 aws-dublin kernel: RCU Tasks Rude: Setting shift to 2 and lim to 1 rcu_task_cb_adjust=1. Aug 01 14:05:51 aws-dublin kernel: RCU Tasks Trace: Setting shift to 2 and lim to 1 rcu_task_cb_adjust=1. Aug 01 14:05:51 aws-dublin kernel: NR_IRQS: 8448, nr_irqs: 456, preallocated irqs: 16 Aug 01 14:05:51 aws-dublin kernel: NO_HZ: Full dynticks CPUs: 1-2. Aug 01 14:05:51 aws-dublin kernel: rcu: Offload RCU callbacks from CPUs: 1-2. Aug 01 14:05:51 aws-dublin kernel: rcu: srcu_init: Setting srcu_struct sizes based on contention. On Thu, 2024-08-01 at 10:28 -0400, Olivier Langlois wrote: > this is with kernel 6.10.2 > > I have these options set on the boot command line: > isolcpus=0,1,2 nohz_full=1,2 rcu_nocbs=1,2 > > $ ps -eo pid,cpuid,comm | grep rcuog > 18 3 rcuog/0 > 38 0 rcuog/2 > > I do not understand why a rcuog task is spawn for cpu0. > I would have expected to have one for cpu1. > > I do have a > 31 3 rcuos/1 > > I am not familiar enough with rcu to know what rcuos is for. > > the absence of of rcuog/1 is causing rcu_irq_work_resched() to raise > an > interrupt every 2-3 seconds on cpu1. > > I am currently reading rcu/tree_nocb.h to try to make sense of what I > am seeing but I am pinging the rcu list just in case what I am seeing > would be immediately obvious to one of you... > > thank you, >
