Re: [RFC PATCH v1 1/6] sched: track time spent in IRQ handler

[Jan Beulich <jbeulich@xxxxxxxx>]

On 12.06.2020 02:22, Volodymyr Babchuk wrote:
> --- a/xen/arch/x86/irq.c
> +++ b/xen/arch/x86/irq.c
> @@ -1895,6 +1895,7 @@ void do_IRQ(struct cpu_user_regs *regs)
>      int               irq = this_cpu(vector_irq)[vector];
>      struct cpu_user_regs *old_regs = set_irq_regs(regs);
>  
> +    vcpu_begin_irq_handler();
>      perfc_incr(irqs);
>      this_cpu(irq_count)++;
>      irq_enter();
> @@ -2024,6 +2025,7 @@ void do_IRQ(struct cpu_user_regs *regs)
>   out_no_unlock:
>      irq_exit();
>      set_irq_regs(old_regs);
> +    vcpu_end_irq_handler();
>  }

This looks like a fight for who's going to be first/last here. I
think you want to add your calls after irq_enter() and before
irq_exit().

Jan