From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3DAADCA9EAF for ; Mon, 21 Oct 2019 02:26:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1E5D421928 for ; Mon, 21 Oct 2019 02:26:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726888AbfJUC0H (ORCPT ); Sun, 20 Oct 2019 22:26:07 -0400 Received: from mga02.intel.com ([134.134.136.20]:24376 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726738AbfJUC0H (ORCPT ); Sun, 20 Oct 2019 22:26:07 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 20 Oct 2019 19:26:06 -0700 X-IronPort-AV: E=Sophos;i="5.67,321,1566889200"; d="scan'208";a="190965593" Received: from likexu-mobl1.ccr.corp.intel.com (HELO [10.239.196.130]) ([10.239.196.130]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/AES256-SHA; 20 Oct 2019 19:26:03 -0700 Subject: Re: [PATCH v2 0/4] KVM: x86/vPMU: Efficiency optimization by reusing last created perf_event From: Like Xu To: Paolo Bonzini Cc: kvm@vger.kernel.org, peterz@infradead.org, Jim Mattson , rkrcmar@redhat.com, sean.j.christopherson@intel.com, vkuznets@redhat.com, Ingo Molnar , Arnaldo Carvalho de Melo , ak@linux.intel.com, wei.w.wang@intel.com, kan.liang@intel.com, like.xu@intel.com, ehankland@google.com, arbel.moshe@oracle.com, linux-kernel@vger.kernel.org References: <20191013091533.12971-1-like.xu@linux.intel.com> Organization: Intel OTC Message-ID: Date: Mon, 21 Oct 2019 10:26:01 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <20191013091533.12971-1-like.xu@linux.intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 2019/10/13 17:15, Like Xu wrote: ... Hi Paolo, Do you have any concerns or comments for the KVM codes (the last two patches) about this vPMU efficiency optimization? Thanks, Like Xu > > --- > Changes in v2: > - use perf_event_pause() to disable, read, reset by only one lock; > - use __perf_event_read_value() after _perf_event_disable(); > - replace bitfields with 'u8 event_count; bool need_cleanup;'; > - refine comments and commit messages; > - fix two issues reported by kbuild test robot for ARCH=[nds32|sh] > > v1: > https://lore.kernel.org/kvm/20190930072257.43352-1-like.xu@linux.intel.com/ > > Like Xu (4): > perf/core: Provide a kernel-internal interface to recalibrate event > period > perf/core: Provide a kernel-internal interface to pause perf_event > KVM: x86/vPMU: Reuse perf_event to avoid unnecessary > pmc_reprogram_counter > KVM: x86/vPMU: Add lazy mechanism to release perf_event per vPMC > > arch/x86/include/asm/kvm_host.h | 17 +++++++ > arch/x86/kvm/pmu.c | 88 ++++++++++++++++++++++++++++++++- > arch/x86/kvm/pmu.h | 15 +++++- > arch/x86/kvm/pmu_amd.c | 14 ++++++ > arch/x86/kvm/vmx/pmu_intel.c | 27 ++++++++++ > arch/x86/kvm/x86.c | 12 +++++ > include/linux/perf_event.h | 10 ++++ > kernel/events/core.c | 44 ++++++++++++++--- > 8 files changed, 216 insertions(+), 11 deletions(-) >