On 2022/11/9 23:20, Frederic Weisbecker wrote: > On Wed, Nov 09, 2022 at 05:37:37PM +0800, Zhen Lei wrote: >> diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c >> index ed93ddb8203d42c..e1ff23b2a14d71d 100644 >> --- a/kernel/rcu/tree.c >> +++ b/kernel/rcu/tree.c >> @@ -866,6 +866,23 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp) >> rdp->rcu_iw_gp_seq = rnp->gp_seq; >> irq_work_queue_on(&rdp->rcu_iw, rdp->cpu); >> } >> + >> + if (rcu_cpu_stall_cputime && rdp->snap_record.gp_seq != rdp->gp_seq) { >> + u64 *cpustat; >> + struct rcu_snap_record *rsrp; >> + >> + cpustat = kcpustat_cpu(rdp->cpu).cpustat; >> + >> + rsrp = &rdp->snap_record; >> + rsrp->cputime_irq = cpustat[CPUTIME_IRQ]; >> + rsrp->cputime_softirq = cpustat[CPUTIME_SOFTIRQ]; >> + rsrp->cputime_system = cpustat[CPUTIME_SYSTEM]; > > You need to use kcpustat_field(), otherwise you'll get stalled values on nohz_full CPUs. OK, I'll update it. Thanks. > >> + rsrp->nr_hardirqs = kstat_cpu_irqs_sum(rdp->cpu); >> + rsrp->nr_softirqs = kstat_cpu_softirqs_sum(rdp->cpu); >> + rsrp->nr_csw = nr_context_switches_cpu(rdp->cpu); >> + rsrp->jiffies = jiffies; >> + rsrp->gp_seq = rdp->gp_seq; >> + } >> } >> >> return 0; >> diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h >> index 5653560573e22d6..7b6afb9c7b96dbe 100644 >> --- a/kernel/rcu/tree_stall.h >> +++ b/kernel/rcu/tree_stall.h >> @@ -428,6 +428,33 @@ static bool rcu_is_rcuc_kthread_starving(struct rcu_data *rdp, unsigned long *jp >> return j > 2 * HZ; >> } >> >> +static void print_cpu_stat_info(int cpu) >> +{ >> + u64 *cpustat; >> + struct rcu_snap_record *rsrp; >> + struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu); >> + >> + if (!rcu_cpu_stall_cputime) >> + return; >> + >> + rsrp = &rdp->snap_record; >> + if (rsrp->gp_seq != rdp->gp_seq) >> + return; >> + >> + cpustat = kcpustat_cpu(cpu).cpustat; >> + >> + pr_err(" hardirqs softirqs csw/system\n"); >> + pr_err(" number: %8ld %10d %12lld\n", >> + kstat_cpu_irqs_sum(cpu) - rsrp->nr_hardirqs, >> + kstat_cpu_softirqs_sum(cpu) - rsrp->nr_softirqs, >> + nr_context_switches_cpu(cpu) - rsrp->nr_csw); >> + pr_err("cputime: %8lld %10lld %12lld ==> %lld(ms)\n", >> + div_u64(cpustat[CPUTIME_IRQ] - rsrp->cputime_irq, NSEC_PER_MSEC), >> + div_u64(cpustat[CPUTIME_SOFTIRQ] - rsrp->cputime_softirq, NSEC_PER_MSEC), >> + div_u64(cpustat[CPUTIME_SYSTEM] - rsrp->cputime_system, >> NSEC_PER_MSEC), > > Same here. OK > > Thanks. > . > -- Regards, Zhen Lei