From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wei Huang Subject: Re: [PATCH] KVM: arm64: Count guest exit due to various reasons Date: Tue, 20 Oct 2015 00:17:47 -0500 Message-ID: <5625CE7B.7080808@redhat.com> References: <1445155482-12482-1-git-send-email-amittomer25@gmail.com> <20151018195304.GA7531@cbox> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 11EDA412C2 for ; Tue, 20 Oct 2015 01:15:21 -0400 (EDT) Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id VQQtdotG9JLr for ; Tue, 20 Oct 2015 01:15:19 -0400 (EDT) Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id 85F8E412AF for ; Tue, 20 Oct 2015 01:15:19 -0400 (EDT) In-Reply-To: <20151018195304.GA7531@cbox> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu To: Christoffer Dall , Amit Cc: marc.zyngier@arm.com, andre.przywara@arm.com, kvmarm@lists.cs.columbia.edu List-Id: kvmarm@lists.cs.columbia.edu On 10/18/2015 02:53 PM, Christoffer Dall wrote: > On Sun, Oct 18, 2015 at 01:34:42PM +0530, Amit wrote: >> From: Amit Singh Tomar >> >> This patch adds guest exit statistics to debugfs, This can be helpful >> while measuring KVM performance. >> >> Signed-off-by: Amit Singh Tomar >> --- >> 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; >> + 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; >> }; >> >> 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++; >> 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 >> > > I thought the idea was to not use this infrastructure anymore and > instead use tracepoints to count exit reasons? > > I'm cc'ing Wei here who sent some patches to QEMU for this purpose > recently. The patches I submitted were for fixing architecture-related issues while running kvm_stat on ARM platforms. I don't think tracepoint is meant to replace debugfs for kvm profiling. Both methods have their own benefits; and they are supported on x86 & ppc platforms. From this perspective I don't mind taking this patch (after review). Thanks, -Wei > > Thanks, > -Christoffer >