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From: "Zhu, Lingshan" <lingshan.zhu@intel.com>
To: "Wang, Wei W" <wei.w.wang@intel.com>,
	Liuxiangdong <liuxiangdong5@huawei.com>,
	"peterz@infradead.org" <peterz@infradead.org>,
	"pbonzini@redhat.com" <pbonzini@redhat.com>
Cc: "bp@alien8.de" <bp@alien8.de>,
	"seanjc@google.com" <seanjc@google.com>,
	"vkuznets@redhat.com" <vkuznets@redhat.com>,
	"wanpengli@tencent.com" <wanpengli@tencent.com>,
	"jmattson@google.com" <jmattson@google.com>,
	"joro@8bytes.org" <joro@8bytes.org>,
	"Yang, Weijiang" <weijiang.yang@intel.com>,
	"kan.liang@linux.intel.com" <kan.liang@linux.intel.com>,
	"ak@linux.intel.com" <ak@linux.intel.com>,
	"eranian@google.com" <eranian@google.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"x86@kernel.org" <x86@kernel.org>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	"like.xu.linux@gmail.com" <like.xu.linux@gmail.com>,
	"Fangyi (Eric)" <eric.fangyi@huawei.com>,
	Xiexiangyou <xiexiangyou@huawei.com>
Subject: Re: [PATCH V7 00/18] KVM: x86/pmu: Add *basic* support to enable guest PEBS via DS
Date: Mon, 28 Jun 2021 15:53:40 +0800	[thread overview]
Message-ID: <1bfecd6b-e05a-c470-ef09-e398de8db521@intel.com> (raw)
In-Reply-To: <81530ac3ebe74ada9b5d1dc8092c1a31@intel.com>



On 6/28/2021 3:49 PM, Wang, Wei W wrote:
> On Friday, June 25, 2021 5:46 PM, Zhu, Lingshan wrote:
>>> Only on the host?
>>> I cannot use pebs unless try with "echo 0 > /proc/sys/kernel/watchdog"
>>> both on the host and guest on ICX.
>> Hi Xiangdong
>>
>> I guess you may run into the "cross-map" case(slow path below), so I think you
>> can disable them both in host and guest to make PEBS work.
>>
> Hi Lingshan, could we also reproduce this issue?
>
> If the guest's watchdog takes away the virtual fixed counter, this will schedule the guest PEBS to use virtual PMC0. With the fast path (1:1 mapping), I think physical PMC0 is likely to be available for the guest PEBS emulation if no other host perf events are running.
I think it is possible, even a virtual counter need a perf event 
scheduled on the host. This depends on the guest / host workloads.

Thanks,
Zhu Lingshan
> Best,
> Wei


  reply	other threads:[~2021-06-28  7:53 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-22  9:42 [PATCH V7 00/18] KVM: x86/pmu: Add *basic* support to enable guest PEBS via DS Zhu Lingshan
2021-06-22  9:42 ` [PATCH V7 01/18] perf/core: Use static_call to optimize perf_guest_info_callbacks Zhu Lingshan
2021-07-02 11:22   ` Peter Zijlstra
2021-07-02 16:00     ` Joe Perches
2021-07-02 16:19       ` Peter Zijlstra
2021-07-02 16:42         ` Joe Perches
2021-07-02 16:38       ` Mark Rutland
2021-07-02 16:56         ` Joe Perches
2021-07-08  8:53     ` Zhu Lingshan
2021-06-22  9:42 ` [PATCH V7 02/18] perf/x86/intel: Add EPT-Friendly PEBS for Ice Lake Server Zhu Lingshan
2021-06-22  9:42 ` [PATCH V7 03/18] perf/x86/intel: Handle guest PEBS overflow PMI for KVM guest Zhu Lingshan
2021-07-02 11:28   ` Peter Zijlstra
2021-07-08 13:39     ` Zhu, Lingshan
2021-06-22  9:42 ` [PATCH V7 04/18] perf/x86/core: Pass "struct kvm_pmu *" to determine the guest values Zhu Lingshan
2021-06-22  9:42 ` [PATCH V7 05/18] KVM: x86/pmu: Set MSR_IA32_MISC_ENABLE_EMON bit when vPMU is enabled Zhu Lingshan
2021-06-22  9:42 ` [PATCH V7 06/18] KVM: x86/pmu: Introduce the ctrl_mask value for fixed counter Zhu Lingshan
2021-06-22  9:42 ` [PATCH V7 07/18] x86/perf/core: Add pebs_capable to store valid PEBS_COUNTER_MASK value Zhu Lingshan
2021-06-22  9:42 ` [PATCH V7 08/18] KVM: x86/pmu: Add IA32_PEBS_ENABLE MSR emulation for extended PEBS Zhu Lingshan
2021-06-22  9:42 ` [PATCH V7 09/18] KVM: x86/pmu: Reprogram PEBS event to emulate guest PEBS counter Zhu Lingshan
2021-06-22  9:42 ` [PATCH V7 10/18] KVM: x86/pmu: Adjust precise_ip to emulate Ice Lake guest PDIR counter Zhu Lingshan
2021-06-22  9:42 ` [PATCH V7 11/18] KVM: x86/pmu: Add IA32_DS_AREA MSR emulation to support guest DS Zhu Lingshan
2021-07-02 11:52   ` Peter Zijlstra
2021-07-08  8:52     ` Zhu, Lingshan
2021-06-22  9:43 ` [PATCH V7 12/18] KVM: x86/pmu: Add PEBS_DATA_CFG MSR emulation to support adaptive PEBS Zhu Lingshan
2021-06-22  9:43 ` [PATCH V7 13/18] KVM: x86: Set PEBS_UNAVAIL in IA32_MISC_ENABLE when PEBS is enabled Zhu Lingshan
2021-06-22  9:43 ` [PATCH V7 14/18] KVM: x86/pmu: Move pmc_speculative_in_use() to arch/x86/kvm/pmu.h Zhu Lingshan
2021-06-22  9:43 ` [PATCH V7 15/18] KVM: x86/pmu: Disable guest PEBS temporarily in two rare situations Zhu Lingshan
2021-07-02 12:46   ` Peter Zijlstra
2021-07-08  8:52     ` Zhu, Lingshan
2021-06-22  9:43 ` [PATCH V7 16/18] KVM: x86/pmu: Add kvm_pmu_cap to optimize perf_get_x86_pmu_capability Zhu Lingshan
2021-06-22  9:43 ` [PATCH V7 17/18] KVM: x86/cpuid: Refactor host/guest CPU model consistency check Zhu Lingshan
2021-06-22  9:43 ` [PATCH V7 18/18] KVM: x86/pmu: Expose CPUIDs feature bits PDCM, DS, DTES64 Zhu Lingshan
2021-06-25  9:40 ` [PATCH V7 00/18] KVM: x86/pmu: Add *basic* support to enable guest PEBS via DS Liuxiangdong
2021-06-25  9:46   ` Zhu, Lingshan
2021-06-28  7:49     ` Wang, Wei W
2021-06-28  7:53       ` Zhu, Lingshan [this message]
2021-07-02 12:49 ` Peter Zijlstra
2021-07-12  1:37 ` Liuxiangdong
2021-07-12 10:34   ` Like Xu

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