From: Sean Christopherson <seanjc@google.com>
To: Dapeng Mi <dapeng1.mi@linux.intel.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>,
Zhenyu Wang <zhenyuw@linux.intel.com>,
Like Xu <like.xu.linux@gmail.com>,
Jinrong Liang <cloudliang@tencent.com>,
Yongwei Ma <yongwei.ma@intel.com>,
Dapeng Mi <dapeng1.mi@intel.com>
Subject: Re: [kvm-unit-tests patch v6 08/18] x86: pmu: Fix cycles event validation failure
Date: Fri, 14 Feb 2025 13:07:57 -0800 [thread overview]
Message-ID: <Z6-wrVaVSiI9ZKkD@google.com> (raw)
In-Reply-To: <20240914101728.33148-9-dapeng1.mi@linux.intel.com>
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.
> +}
> +
> 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:[~2025-02-14 21:07 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 [this message]
2025-02-18 9:36 ` Mi, Dapeng
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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