Re: [PATCH v2 1/7] sched/fair: Fix zero_vruntime tracking

[John Stultz]

On Tue, Mar 31, 2026 at 9:14 AM Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> On Tue, Mar 31, 2026 at 02:20:35PM +0200, Peter Zijlstra wrote:
>
> I'm thinking this might help... I'll try once I'm back home again.
>
>
> diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
> index b24f40f05019..15bf45b6f912 100644
> --- a/kernel/sched/debug.c
> +++ b/kernel/sched/debug.c
> @@ -902,6 +902,7 @@ static void print_rq(struct seq_file *m, struct rq *rq, int rq_cpu)
>  void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
>  {
>         s64 left_vruntime = -1, zero_vruntime, right_vruntime = -1, left_deadline = -1, spread;
> +       u64 avruntime;
>         struct sched_entity *last, *first, *root;
>         struct rq *rq = cpu_rq(cpu);
>         unsigned long flags;
> @@ -925,6 +926,7 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
>         if (last)
>                 right_vruntime = last->vruntime;
>         zero_vruntime = cfs_rq->zero_vruntime;
> +       avruntime = avg_vruntime(cfs_rq);
>         raw_spin_rq_unlock_irqrestore(rq, flags);
>
>         SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "left_deadline",
> @@ -934,7 +936,7 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
>         SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "zero_vruntime",
>                         SPLIT_NS(zero_vruntime));
>         SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "avg_vruntime",
> -                       SPLIT_NS(avg_vruntime(cfs_rq)));
> +                       SPLIT_NS(avruntime));
>         SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "right_vruntime",
>                         SPLIT_NS(right_vruntime));
>         spread = right_vruntime - left_vruntime;
>

This on top of your two previous changes has run for 5 hours for me
now, which is usually where I'd call things "good" when bisecting.

I'm going to leave it overnight, but tentatively:

Tested-by: John Stultz <jstultz@xxxxxxxxxx>

thanks
-john