From: "Mi, Dapeng" <dapeng1.mi@linux.intel.com>
To: Sean Christopherson <seanjc@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Jim Mattson <jmattson@google.com>,
Mingwei Zhang <mizhang@google.com>,
Xiong Zhang <xiong.y.zhang@intel.com>,
Like Xu <like.xu.linux@gmail.com>,
Jinrong Liang <cloudliang@tencent.com>,
Dapeng Mi <dapeng1.mi@intel.com>
Subject: Re: [kvm-unit-tests patch v6 08/18] x86: pmu: Fix cycles event validation failure
Date: Tue, 18 Feb 2025 17:36:19 +0800 [thread overview]
Message-ID: <add089ff-49d9-40a9-a020-5f4eb876aef8@linux.intel.com> (raw)
In-Reply-To: <Z6-wrVaVSiI9ZKkD@google.com>
On 2/15/2025 5:07 AM, Sean Christopherson wrote:
> On Sat, Sep 14, 2024, Dapeng Mi wrote:
>> +static void warm_up(void)
>> +{
>> + int i = 8;
>> +
>> + /*
>> + * Since cycles event is always run as the first event, there would be
>> + * a warm-up state to warm up the cache, it leads to the measured cycles
>> + * value may exceed the pre-defined cycles upper boundary and cause
>> + * false positive. To avoid this, introduce an warm-up state before
>> + * the real verification.
>> + */
>> + while (i--)
>> + loop();
> Use a for-loop.
Sure.
>
>> +}
>> +
>> static void check_counters(void)
>> {
>> if (is_fep_available())
>> check_emulated_instr();
>>
>> + warm_up();
>> check_gp_counters();
>> check_fixed_counters();
>> check_rdpmc();
>> --
>> 2.40.1
>>
next prev parent reply other threads:[~2025-02-18 9:36 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-09-14 10:17 [kvm-unit-tests patch v6 00/18] pmu test bugs fix and improvements Dapeng Mi
2024-09-14 10:17 ` [kvm-unit-tests patch v6 01/18] x86: pmu: Remove duplicate code in pmu_init() Dapeng Mi
2024-09-14 10:17 ` [kvm-unit-tests patch v6 02/18] x86: pmu: Remove blank line and redundant space Dapeng Mi
2024-09-14 10:17 ` [kvm-unit-tests patch v6 03/18] x86: pmu: Refine fixed_events[] names Dapeng Mi
2024-09-14 10:17 ` [kvm-unit-tests patch v6 04/18] x86: pmu: Fix the issue that pmu_counter_t.config crosses cache line Dapeng Mi
2025-02-14 21:05 ` Sean Christopherson
2025-02-18 9:07 ` Mi, Dapeng
2024-09-14 10:17 ` [kvm-unit-tests patch v6 05/18] x86: pmu: Enlarge cnt[] length to 48 in check_counters_many() Dapeng Mi
2025-02-14 21:06 ` Sean Christopherson
2025-02-18 9:24 ` Mi, Dapeng
2025-02-18 15:56 ` Sean Christopherson
2024-09-14 10:17 ` [kvm-unit-tests patch v6 06/18] x86: pmu: Print measured event count if test fails Dapeng Mi
2024-09-14 10:17 ` [kvm-unit-tests patch v6 07/18] x86: pmu: Fix potential out of bound access for fixed events Dapeng Mi
2025-02-14 21:07 ` Sean Christopherson
2025-02-18 9:34 ` Mi, Dapeng
2025-02-18 15:04 ` Sean Christopherson
2024-09-14 10:17 ` [kvm-unit-tests patch v6 08/18] x86: pmu: Fix cycles event validation failure Dapeng Mi
2025-02-14 21:07 ` Sean Christopherson
2025-02-18 9:36 ` Mi, Dapeng [this message]
2024-09-14 10:17 ` [kvm-unit-tests patch v6 09/18] x86: pmu: Use macro to replace hard-coded branches event index Dapeng Mi
2024-09-14 10:17 ` [kvm-unit-tests patch v6 10/18] x86: pmu: Use macro to replace hard-coded ref-cycles " Dapeng Mi
2024-09-14 10:17 ` [kvm-unit-tests patch v6 11/18] x86: pmu: Use macro to replace hard-coded instructions " Dapeng Mi
2024-09-14 10:17 ` [kvm-unit-tests patch v6 12/18] x86: pmu: Enable and disable PMCs in loop() asm blob Dapeng Mi
2024-09-14 10:17 ` [kvm-unit-tests patch v6 13/18] x86: pmu: Improve instruction and branches events verification Dapeng Mi
2025-02-14 21:08 ` Sean Christopherson
2025-02-18 9:40 ` Mi, Dapeng
2024-09-14 10:17 ` [kvm-unit-tests patch v6 14/18] x86: pmu: Improve LLC misses event verification Dapeng Mi
2024-09-14 10:17 ` [kvm-unit-tests patch v6 15/18] x86: pmu: Adjust lower boundary of llc-misses event to 0 for legacy CPUs Dapeng Mi
2024-09-14 10:17 ` [kvm-unit-tests patch v6 16/18] x86: pmu: Add IBPB indirect jump asm blob Dapeng Mi
2024-09-14 10:17 ` [kvm-unit-tests patch v6 17/18] x86: pmu: Adjust lower boundary of branch-misses event Dapeng Mi
2025-02-14 21:09 ` Sean Christopherson
2025-02-18 9:42 ` Mi, Dapeng
2024-09-14 10:17 ` [kvm-unit-tests patch v6 18/18] x86: pmu: Optimize emulated instruction validation Dapeng Mi
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