From: Sandipan Das <sandipan.das@amd.com>
To: Like Xu <like.xu.linux@gmail.com>
Cc: peterz@infradead.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, eranian@google.com,
puwen@hygon.cn, ananth.narayan@amd.com, ravi.bangoria@amd.com,
santosh.shukla@amd.com,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
linux-perf-users@vger.kernel.org, x86@kernel.org
Subject: Re: [PATCH v4 3/7] perf/x86/amd/core: Detect PerfMonV2 support
Date: Mon, 9 May 2022 18:38:19 +0530 [thread overview]
Message-ID: <96e41431-eb80-f61d-9ab9-c76cd9b6086a@amd.com> (raw)
In-Reply-To: <78e001bd-42bd-5481-5a19-1a0bcca9a63c@gmail.com>
On 5/9/2022 6:31 PM, Like Xu wrote:
> On 27/4/2022 7:31 pm, Sandipan Das wrote:
>
>> x86_pmu.num_counters = AMD64_NUM_COUNTERS_CORE;
>
> Thus boot_cpu_has(X86_FEATURE_PERFCTR_CORE) is true.
>
>> +
>> + /* Check for Performance Monitoring v2 support */
>> + if (boot_cpu_has(X86_FEATURE_PERFMON_V2)) {
>> + /* Update PMU version for later usage */
>> + x86_pmu.version = 2;
>
> Is it safe to assume that once AMD CPU has the PERFMON_V2 (or further) bit,
>
> it must also have the PERFCTR_CORE bit set ?
>
Yes, always. There won't be a case where PERFCTR_CORE is absent
but PERFMON_V2 is present.
- Sandipan
next prev parent reply other threads:[~2022-05-09 13:08 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-27 11:31 [PATCH v4 0/7] perf/x86/amd/core: Add AMD " Sandipan Das
2022-04-27 11:31 ` [PATCH v4 1/7] x86/cpufeatures: Add PerfMonV2 feature bit Sandipan Das
2022-04-27 11:31 ` [PATCH v4 2/7] x86/msr: Add PerfCntrGlobal* registers Sandipan Das
2022-04-27 11:31 ` [PATCH v4 3/7] perf/x86/amd/core: Detect PerfMonV2 support Sandipan Das
2022-05-09 13:01 ` Like Xu
2022-05-09 13:08 ` Sandipan Das [this message]
2022-05-09 13:11 ` Peter Zijlstra
2022-05-10 8:36 ` Sandipan Das
2022-04-27 11:31 ` [PATCH v4 4/7] perf/x86/amd/core: Detect available counters Sandipan Das
2022-04-27 11:31 ` [PATCH v4 5/7] perf/x86/amd/core: Add PerfMonV2 counter control Sandipan Das
2022-05-09 7:05 ` Like Xu
2022-05-09 9:58 ` Sandipan Das
2022-05-09 11:24 ` Peter Zijlstra
2022-04-27 11:31 ` [PATCH v4 6/7] perf/x86/amd/core: Add PerfMonV2 overflow handling Sandipan Das
2022-04-28 13:40 ` Like Xu
2022-04-29 5:10 ` Sandipan Das
2022-04-27 11:31 ` [PATCH v4 7/7] kvm: x86/cpuid: Fix CPUID leaf 0xA Sandipan Das
2022-05-02 23:50 ` Jim Mattson
2022-05-03 12:01 ` Paolo Bonzini
2022-05-03 12:04 ` Paolo Bonzini
2022-04-27 11:37 ` [PATCH v4 0/7] perf/x86/amd/core: Add AMD PerfMonV2 support Borislav Petkov
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