On Sun, Oct 18, 2015 at 01:34:42PM +0530, Amit wrote:
> From: Amit Singh Tomar <amittomer25@xxxxxxxxx>
>
> This patch adds guest exit statistics to debugfs, This can be helpful
> while measuring KVM performance.
>
> Signed-off-by: Amit Singh Tomar <amittomer25@xxxxxxxxx>
> ---
> arch/arm/include/asm/kvm_host.h | 2 ++
> arch/arm/kvm/arm.c | 1 +
> arch/arm/kvm/guest.c | 2 ++
> arch/arm/kvm/mmio.c | 1 +
> arch/arm64/include/asm/kvm_host.h | 5 +++++
> arch/arm64/kvm/guest.c | 8 ++++++++
> arch/arm64/kvm/handle_exit.c | 3 +++
> 7 files changed, 22 insertions(+)
>
> diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
> index c4072d9..d1f3159 100644
> --- a/arch/arm/include/asm/kvm_host.h
> +++ b/arch/arm/include/asm/kvm_host.h
> @@ -147,6 +147,8 @@ struct kvm_vcpu_stat {
> u32 halt_successful_poll;
> u32 halt_attempted_poll;
> u32 halt_wakeup;
> + u32 mmio_exit_stat;
I think it would be even more useful to distinguish between mmio exits
handled in the kernel vs. those going to userspace.
> + u32 exits;
> };
>
> int kvm_vcpu_preferred_target(struct kvm_vcpu_init *init);
> diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
> index 78b2869..5d0a2c5 100644
> --- a/arch/arm/kvm/arm.c
> +++ b/arch/arm/kvm/arm.c
> @@ -569,6 +569,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
> ret = kvm_call_hyp(__kvm_vcpu_run, vcpu);
>
> vcpu->mode = OUTSIDE_GUEST_MODE;
> + vcpu->stat.exits++;
> /*
> * Back from guest
> *************************************************************/
> diff --git a/arch/arm/kvm/guest.c b/arch/arm/kvm/guest.c
> index 96e935b..0eea5fc 100644
> --- a/arch/arm/kvm/guest.c
> +++ b/arch/arm/kvm/guest.c
> @@ -33,6 +33,8 @@
> #define VCPU_STAT(x) { #x, offsetof(struct kvm_vcpu, stat.x), KVM_STAT_VCPU }
>
> struct kvm_stats_debugfs_item debugfs_entries[] = {
> + VCPU_STAT(mmio_exit_stat),
> + VCPU_STAT(exits),
> { NULL }
> };
>
> diff --git a/arch/arm/kvm/mmio.c b/arch/arm/kvm/mmio.c
> index 974b1c6..51d518e 100644
> --- a/arch/arm/kvm/mmio.c
> +++ b/arch/arm/kvm/mmio.c
> @@ -184,6 +184,7 @@ int io_mem_abort(struct kvm_vcpu *vcpu, struct kvm_run *run,
> }
>
> rt = vcpu->arch.mmio_decode.rt;
> + vcpu->stat.mmio_exit_stat++;
>
> if (is_write) {
> data = vcpu_data_guest_to_host(vcpu, *vcpu_reg(vcpu, rt), len);
> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> index ed03968..b32c938 100644
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -194,6 +194,11 @@ struct kvm_vcpu_stat {
> u32 halt_successful_poll;
> u32 halt_attempted_poll;
> u32 halt_wakeup;
> + u32 hvc_exit_stat;
> + u32 wfx_exit_stat;
> + u32 wfi_exit_stat;
> + u32 mmio_exit_stat;
> + u32 exits;
why more exit stats on arm64 than on arm?
why u32? Would it not make sense to make these u64 or just unsigned
long?
> };
>
> int kvm_vcpu_preferred_target(struct kvm_vcpu_init *init);
> diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
> index d250160..b1943cd 100644
> --- a/arch/arm64/kvm/guest.c
> +++ b/arch/arm64/kvm/guest.c
> @@ -34,7 +34,15 @@
>
> #include "trace.h"
>
> +#define VM_STAT(x) { #x, offsetof(struct kvm, stat.x), KVM_STAT_VM }
> +#define VCPU_STAT(x) { #x, offsetof(struct kvm_vcpu, stat.x), KVM_STAT_VCPU }
> +
> struct kvm_stats_debugfs_item debugfs_entries[] = {
> + VCPU_STAT(hvc_exit_stat),
> + VCPU_STAT(wfx_exit_stat),
> + VCPU_STAT(wfi_exit_stat),
> + VCPU_STAT(mmio_exit_stat),
> + VCPU_STAT(exits),
> { NULL }
> };
>
> diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
> index 68a0759..6e38c50 100644
> --- a/arch/arm64/kvm/handle_exit.c
> +++ b/arch/arm64/kvm/handle_exit.c
> @@ -39,6 +39,7 @@ static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
>
> trace_kvm_hvc_arm64(*vcpu_pc(vcpu), *vcpu_reg(vcpu, 0),
> kvm_vcpu_hvc_get_imm(vcpu));
> + vcpu->stat.hvc_exit_stat++;
>
> ret = kvm_psci_call(vcpu);
> if (ret < 0) {
> @@ -71,9 +72,11 @@ static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run)
> {
> if (kvm_vcpu_get_hsr(vcpu) & ESR_ELx_WFx_ISS_WFE) {
> trace_kvm_wfx_arm64(*vcpu_pc(vcpu), true);
> + vcpu->stat.wfx_exit_stat++;
either you should use one called wfx_exit_stat or you should distinguish
between wfi and wfe; this is just a weird way of doing it.
> kvm_vcpu_on_spin(vcpu);
> } else {
> trace_kvm_wfx_arm64(*vcpu_pc(vcpu), false);
> + vcpu->stat.wfi_exit_stat++;
> kvm_vcpu_block(vcpu);
> }
>
> --
> 1.9.1
>
Thanks,
-Christoffer
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