From: Like Xu <like.xu@linux.intel.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
kvm@vger.kernel.org,
Sean Christopherson <sean.j.christopherson@intel.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
Kan Liang <kan.liang@linux.intel.com>,
luwei.kang@intel.com, Thomas Gleixner <tglx@linutronix.de>,
wei.w.wang@intel.com, Tony Luck <tony.luck@intel.com>,
Stephane Eranian <eranian@google.com>,
Mark Gross <mgross@linux.intel.com>,
Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] perf/intel: Remove Perfmon-v4 counter_freezing support
Date: Mon, 16 Nov 2020 11:22:24 +0800 [thread overview]
Message-ID: <11ba9e20-84eb-3ea5-5987-8357ae5af53f@linux.intel.com> (raw)
In-Reply-To: <20201110153721.GQ2651@hirez.programming.kicks-ass.net>
Hi Peter,
On 2020/11/10 23:37, Peter Zijlstra wrote:
> -static int __init intel_perf_counter_freezing_setup(char *s)
> -{
> - bool res;
> -
> - if (kstrtobool(s, &res))
> - return -EINVAL;
> -
> - disable_counter_freezing = !res;
> - return 1;
> -}
> -__setup("perf_v4_pmi=", intel_perf_counter_freezing_setup);
...
> Anyway, as it stands I think the whole counter_freezing thing is a
> trainwreck and it needs to go.
If you really want to drop the counter_freezing stuff, we also need
to clean it up in Documentation/admin-guide/kernel-parameters.txt:
perf_v4_pmi= [X86,INTEL]
Format: <bool>
Disable Intel PMU counter freezing feature.
The feature only exists starting from
Arch Perfmon v4 (Skylake and newer).
However someone may still need it based on the correct understanding
of "Freeze-on-Overflow" as Stephane said. How about renaming and
documenting it instead of discarding it completely?
Our guest PEBS enabling patches does not completely depend on it
and we do not require the administrator to enable perf_v4_pmi for
guest PEBS.
Would you generously take a look at the perf part in this series?
Thanks,
Like Xu
prev parent reply other threads:[~2020-11-16 3:23 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-09 2:12 [PATCH RFC v2 00/17] KVM: x86/pmu: Add support to enable Guest PEBS via DS Like Xu
2020-11-09 2:12 ` [PATCH v2 01/17] KVM: x86/pmu: Set MSR_IA32_MISC_ENABLE_EMON bit when vPMU is enabled Like Xu
2020-11-09 2:12 ` [PATCH v2 02/17] KVM: vmx/pmu: Use IA32_PERF_CAPABILITIES to adjust features visibility Like Xu
2020-11-09 2:12 ` [PATCH v2 03/17] KVM: x86/pmu: Introduce the ctrl_mask value for fixed counter Like Xu
2020-11-09 2:12 ` [PATCH v2 04/17] perf: x86/ds: Handle guest PEBS overflow PMI and inject it to guest Like Xu
2020-11-17 14:35 ` Peter Zijlstra
2020-11-18 16:15 ` Like Xu
2020-11-18 18:07 ` Peter Zijlstra
2020-11-19 1:36 ` Xu, Like
2020-11-27 2:14 ` Xu, Like
2020-11-30 10:49 ` Peter Zijlstra
2020-12-01 1:25 ` Xu, Like
2020-11-09 2:12 ` [PATCH v2 05/17] KVM: x86/pmu: Reprogram guest PEBS event to emulate guest PEBS counter Like Xu
2020-11-17 14:41 ` Peter Zijlstra
2020-11-18 16:18 ` Like Xu
2020-11-09 2:12 ` [PATCH v2 06/17] KVM: x86/pmu: Add IA32_PEBS_ENABLE MSR emulation for extended PEBS Like Xu
2020-11-09 2:12 ` [PATCH v2 07/17] KVM: x86/pmu: Add IA32_DS_AREA MSR emulation to manage guest DS buffer Like Xu
2020-11-09 2:12 ` [PATCH v2 08/17] KVM: x86/pmu: Add PEBS_DATA_CFG MSR emulation to support adaptive PEBS Like Xu
2020-11-09 2:12 ` [PATCH v2 09/17] KVM: x86: Set PEBS_UNAVAIL in IA32_MISC_ENABLE when PEBS is enabled Like Xu
2020-11-09 2:12 ` [PATCH v2 10/17] KVM: x86/pmu: Expose CPUIDs feature bits PDCM, DS, DTES64 Like Xu
2020-11-09 2:12 ` [PATCH v2 11/17] KVM: x86/pmu: Adjust precise_ip to emulate Ice Lake guest PDIR counter Like Xu
2020-11-09 2:12 ` [PATCH v2 12/17] KVM: x86/pmu: Disable guest PEBS when counters are cross-mapped Like Xu
2020-11-09 2:12 ` [PATCH RFC v2 13/17] KVM: x86/pmu: Add hook to emulate pebs for cross-mapped counters Like Xu
2020-11-09 2:12 ` [PATCH RFC v2 14/17] KVM: vmx/pmu: Limit pebs_interrupt_threshold in the guest DS area Like Xu
2020-11-09 2:12 ` [PATCH RFC v2 15/17] KVM: vmx/pmu: Rewrite applicable_counters field in the guest PEBS record Like Xu
2020-11-09 2:12 ` [PATCH RFC v2 16/17] KVM: x86/pmu: Save guest pebs reset value when a pebs counter is configured Like Xu
2020-11-09 2:12 ` [PATCH RFC v2 17/17] KVM: x86/pmu: Adjust guest DS pebs reset counter values for mapped counter Like Xu
2020-11-10 15:12 ` [PATCH RFC v2 00/17] KVM: x86/pmu: Add support to enable Guest PEBS via DS Peter Zijlstra
2020-11-10 15:37 ` [PATCH] perf/intel: Remove Perfmon-v4 counter_freezing support Peter Zijlstra
2020-11-10 20:52 ` Stephane Eranian
2020-11-11 2:42 ` Xu, Like
2021-01-26 9:51 ` Paolo Bonzini
2021-01-26 10:36 ` Peter Zijlstra
2021-01-26 11:35 ` Xu, Like
2021-01-26 11:59 ` Paolo Bonzini
2020-11-11 8:38 ` Peter Zijlstra
2020-11-16 3:22 ` Like Xu [this message]
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