Re: [patch 3/3] KVM: x86: add tracepoint to wait_lapic_expire

[Radim Krcmar <rkrcmar@redhat.com>]

2014-12-16 09:08-0500, Marcelo Tosatti:
> Add tracepoint to wait_lapic_expire.
> 
> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>

> +++ kvm/arch/x86/kvm/lapic.c
> @@ -1120,7 +1120,7 @@ static bool lapic_timer_int_injected(str
>  void wait_lapic_expire(struct kvm_vcpu *vcpu)
>  {
>  	struct kvm_lapic *apic = vcpu->arch.apic;
> -	u64 guest_tsc, tsc_deadline;
> +	u64 orig_guest_tsc, guest_tsc, tsc_deadline;
>  
>  	if (!kvm_vcpu_has_lapic(vcpu))
>  		return;
> @@ -1133,7 +1133,7 @@ void wait_lapic_expire(struct kvm_vcpu *
>  
>  	tsc_deadline = apic->lapic_timer.expired_tscdeadline;
>  	apic->lapic_timer.expired_tscdeadline = 0;
> -	guest_tsc = kvm_x86_ops->read_l1_tsc(vcpu, native_read_tsc());
> +	orig_guest_tsc = guest_tsc = kvm_x86_ops->read_l1_tsc(vcpu, native_read_tsc());

(We could move the tracepoint here and save orig_guest_tsc.)

>  	while (guest_tsc < tsc_deadline) {
>  		int delay = min(tsc_deadline - guest_tsc, 1000ULL);
> @@ -1141,6 +1141,8 @@ void wait_lapic_expire(struct kvm_vcpu *
>  		__delay(delay);
>  		guest_tsc = kvm_x86_ops->read_l1_tsc(vcpu, native_read_tsc());
>  	}
> +
> +	trace_kvm_wait_lapic_expire(vcpu->vcpu_id, orig_guest_tsc - tsc_deadline);
>  }
>