Re: [Xen-devel] Xen optimization

[Milan Boberic <milanboberic94@xxxxxxxxx>]

Hi,

> I think we want to fully understand how many other interrupts the
> baremetal guest is receiving. To do that, we can modify my previous
> patch to suppress any debug messages for virq=68. That way, we should
> only see the other interrupts. Ideally there would be none.
> diff --git a/xen/arch/arm/vgic.c b/xen/arch/arm/vgic.c
> index 5a4f082..b7a8e17 100644
> --- a/xen/arch/arm/vgic.c
> +++ b/xen/arch/arm/vgic.c
> @@ -577,7 +577,11 @@ void vgic_inject_irq(struct domain *d, struct vcpu *v, 
> unsigned int virq,
>      /* the irq is enabled */
>      if ( test_bit(GIC_IRQ_GUEST_ENABLED, &n->status) )
> +    {
>          gic_raise_guest_irq(v, virq, priority);
> +        if ( d->domain_id != 0 && virq != 68 )
> +            printk("DEBUG virq=%d local=%d\n",virq,v == current);
> +    }
>      list_for_each_entry ( iter, &v->arch.vgic.inflight_irqs, inflight )
>      {

when I apply this patch there are no prints nor debug messages in xl
dmesg. So bare-metal receives only interrupt 68, which is good.

> Next step would be to verify that there are no other physical interrupts
> interrupting the vcpu execution other the irq=68. We should be able to
> check that with the following debug patch:
>
> diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c
> index e524ad5..b34c3e4 100644
> --- a/xen/arch/arm/gic.c
> +++ b/xen/arch/arm/gic.c
> @@ -381,6 +381,13 @@ void gic_interrupt(struct cpu_user_regs *regs, int 
> is_fiq)
>          /* Reading IRQ will ACK it */
>          irq = gic_hw_ops->read_irq();
> +        if (current->domain->domain_id > 0 && irq != 68)
> +        {
> +            local_irq_enable();
> +            printk("DEBUG irq=%d\n",irq);
> +            local_irq_disable();
> +        }
> +
>          if ( likely(irq >= 16 && irq < 1020) )
>          {
>              local_irq_enable();

But when I apply this patch it prints forever:
(XEN) DEBUG irq=1023

Thanks in advance!

Milan

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