[PATCH] KVM: MMU: increment stats after event occurrence

[PATCH] KVM: MMU: increment stats after event occurrence

[Davidlohr Bueso]

From: Davidlohr Bueso <dave@gnu.org>

It makes more sense to actually increment statistics for tlb flushes and page table entry updates after such _events_ occur, instead of before.

Signed-off-by: Davidlohr Bueso <dave@gnu.org>
---
 arch/x86/kvm/mmu.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 2a2a9b4..0b7008e 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -3130,8 +3130,8 @@ static int nonpaging_init_context(struct kvm_vcpu *vcpu,
 
 void kvm_mmu_flush_tlb(struct kvm_vcpu *vcpu)
 {
-	++vcpu->stat.tlb_flush;
 	kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
+	++vcpu->stat.tlb_flush;
 }
 
 static void paging_new_cr3(struct kvm_vcpu *vcpu)
@@ -3486,8 +3486,8 @@ static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu,
 		return;
         }
 
-	++vcpu->kvm->stat.mmu_pte_updated;
 	vcpu->arch.mmu.update_pte(vcpu, sp, spte, new);
+	++vcpu->kvm->stat.mmu_pte_updated;
 }
 
 static bool need_remote_flush(u64 old, u64 new)
-- 
1.7.4.1

Re: [PATCH] KVM: MMU: increment stats after event occurrence

[Takuya Yoshikawa]

(2012/01/13 10:08), Davidlohr Bueso wrote:
> From: Davidlohr Bueso<dave@gnu.org>
>
> It makes more sense to actually increment statistics for tlb flushes and page table entry updates after such _events_ occur, instead of before.

Why?

	Takuya

>
> Signed-off-by: Davidlohr Bueso<dave@gnu.org>
> ---
>   arch/x86/kvm/mmu.c |    4 ++--
>   1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> index 2a2a9b4..0b7008e 100644
> --- a/arch/x86/kvm/mmu.c
> +++ b/arch/x86/kvm/mmu.c
> @@ -3130,8 +3130,8 @@ static int nonpaging_init_context(struct kvm_vcpu *vcpu,
>
>   void kvm_mmu_flush_tlb(struct kvm_vcpu *vcpu)
>   {
> -	++vcpu->stat.tlb_flush;
>   	kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
> +	++vcpu->stat.tlb_flush;
>   }
>
>   static void paging_new_cr3(struct kvm_vcpu *vcpu)
> @@ -3486,8 +3486,8 @@ static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu,
>   		return;
>           }
>
> -	++vcpu->kvm->stat.mmu_pte_updated;
>   	vcpu->arch.mmu.update_pte(vcpu, sp, spte, new);
> +	++vcpu->kvm->stat.mmu_pte_updated;
>   }
>
>   static bool need_remote_flush(u64 old, u64 new)

Re: [PATCH] KVM: MMU: increment stats after event occurrence

[Davidlohr Bueso]

On Fri, 2012-01-13 at 10:24 +0900, Takuya Yoshikawa wrote:
> (2012/01/13 10:08), Davidlohr Bueso wrote:
> > From: Davidlohr Bueso<dave@gnu.org>
> >
> > It makes more sense to actually increment statistics for tlb flushes and page table entry updates after such _events_ occur, instead of before.
> 
> Why?
> 
>From a logical point of view its better to increase stats once the event
is processed - usually because it can fail and therefore the stats would
be incorrect. 

> 	Takuya
> 
> >
> > Signed-off-by: Davidlohr Bueso<dave@gnu.org>
> > ---
> >   arch/x86/kvm/mmu.c |    4 ++--
> >   1 files changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> > index 2a2a9b4..0b7008e 100644
> > --- a/arch/x86/kvm/mmu.c
> > +++ b/arch/x86/kvm/mmu.c
> > @@ -3130,8 +3130,8 @@ static int nonpaging_init_context(struct kvm_vcpu *vcpu,
> >
> >   void kvm_mmu_flush_tlb(struct kvm_vcpu *vcpu)
> >   {
> > -	++vcpu->stat.tlb_flush;
> >   	kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
> > +	++vcpu->stat.tlb_flush;
> >   }
> >
> >   static void paging_new_cr3(struct kvm_vcpu *vcpu)
> > @@ -3486,8 +3486,8 @@ static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu,
> >   		return;
> >           }
> >
> > -	++vcpu->kvm->stat.mmu_pte_updated;
> >   	vcpu->arch.mmu.update_pte(vcpu, sp, spte, new);
> > +	++vcpu->kvm->stat.mmu_pte_updated;
> >   }
> >
> >   static bool need_remote_flush(u64 old, u64 new)
> 
> 

Re: [PATCH] KVM: MMU: increment stats after event occurrence

[Avi Kivity]

On 01/13/2012 02:56 PM, Davidlohr Bueso wrote:
> On Fri, 2012-01-13 at 10:24 +0900, Takuya Yoshikawa wrote:
> > (2012/01/13 10:08), Davidlohr Bueso wrote:
> > > From: Davidlohr Bueso<dave@gnu.org>
> > >
> > > It makes more sense to actually increment statistics for tlb flushes and page table entry updates after such _events_ occur, instead of before.
> > 
> > Why?
> > 
> From a logical point of view its better to increase stats once the event
> is processed - usually because it can fail and therefore the stats would
> be incorrect. 
>

That doesn't hold for the cases you change.

-- 
error compiling committee.c: too many arguments to function