From: Peter Zijlstra <peterz@infradead.org>
To: Sandipan Das <sandipan.das@amd.com>
Cc: linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org,
x86@kernel.org, bp@alien8.de, dave.hansen@linux.intel.com,
acme@kernel.org, mark.rutland@arm.com,
alexander.shishkin@linux.intel.com, namhyung@kernel.org,
jolsa@kernel.org, tglx@linutronix.de, mingo@redhat.com,
pbonzini@redhat.com, jmattson@google.com,
like.xu.linux@gmail.com, eranian@google.com,
ananth.narayan@amd.com, ravi.bangoria@amd.com,
santosh.shukla@amd.com
Subject: Re: [PATCH 3/7] perf/x86/amd/core: Detect PerfMonV2 support
Date: Thu, 17 Mar 2022 12:27:24 +0100 [thread overview]
Message-ID: <YjMbHKwtOKJTfVIh@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <1ddd003765ac0d057b2137eab869be4ffee69473.1647498015.git.sandipan.das@amd.com>
On Thu, Mar 17, 2022 at 11:58:32AM +0530, Sandipan Das wrote:
> AMD Performance Monitoring Version 2 (PerfMonV2) introduces
> some new Core PMU features such as detection of the number
> of available PMCs and managing PMCs using global registers
> namely, PerfCntrGlobalCtl and PerfCntrGlobalStatus.
>
> Clearing PerfCntrGlobalCtl and PerfCntrGlobalStatus ensures
> that all PMCs are inactive and have no pending overflows
> when CPUs are onlined or offlined.
>
> The PMU version (x86_pmu.version) now indicates PerfMonV2
> support and will be used to bypass the new features on
> unsupported processors.
>
> Signed-off-by: Sandipan Das <sandipan.das@amd.com>
> ---
> +static void amd_pmu_cpu_reset(int cpu)
> +{
> + if (x86_pmu.version < 2)
> + return;
> +
> + /* Clear enable bits i.e. PerfCntrGlobalCtl.PerfCntrEn */
> + wrmsrl_on_cpu(cpu, MSR_AMD64_PERF_CNTR_GLOBAL_CTL, 0);
> +
> + /* Clear overflow bits i.e. PerfCntrGLobalStatus.PerfCntrOvfl */
> + wrmsrl_on_cpu(cpu, MSR_AMD64_PERF_CNTR_GLOBAL_STATUS_CLR,
> + amd_pmu_global_cntr_mask);
> +}
I think these can be wrmsrl() both starting and dead run on the target
cpu.
next prev parent reply other threads:[~2022-03-17 11:27 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-17 6:28 [PATCH 0/7] perf/x86/amd/core: Add AMD PerfMonV2 support Sandipan Das
2022-03-17 6:28 ` [PATCH 1/7] x86/cpufeatures: Add PerfMonV2 feature bit Sandipan Das
2022-03-17 6:28 ` [PATCH 2/7] x86/msr: Add PerfCntrGlobal* registers Sandipan Das
2022-03-17 11:25 ` Peter Zijlstra
2022-03-17 6:28 ` [PATCH 3/7] perf/x86/amd/core: Detect PerfMonV2 support Sandipan Das
2022-03-17 11:27 ` Peter Zijlstra [this message]
2022-03-17 6:28 ` [PATCH 4/7] perf/x86/amd/core: Detect available counters Sandipan Das
2022-03-17 11:32 ` Peter Zijlstra
2022-03-17 6:28 ` [PATCH 5/7] perf/x86/amd/core: Add PerfMonV2 counter control Sandipan Das
2022-03-17 11:46 ` Peter Zijlstra
2022-03-18 8:02 ` Sandipan Das
2022-03-18 10:52 ` Peter Zijlstra
2022-03-17 6:28 ` [PATCH 6/7] perf/x86/amd/core: Add PerfMonV2 overflow handling Sandipan Das
2022-03-17 12:01 ` Peter Zijlstra
2022-03-17 17:45 ` Stephane Eranian
2022-03-18 8:18 ` Sandipan Das
2022-03-22 7:06 ` Like Xu
2022-03-22 8:37 ` Sandipan Das
2022-03-17 6:28 ` [PATCH 7/7] kvm: x86/cpuid: Fix Architectural Performance Monitoring support Sandipan Das
2022-03-17 12:07 ` Peter Zijlstra
2022-03-18 7:59 ` Sandipan Das
2022-03-22 7:31 ` Like Xu
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