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=-0.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 7DD97C432C3 for ; Thu, 14 Nov 2019 03:51:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 77B5A206E1 for ; Thu, 14 Nov 2019 03:51:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="O5PrQ1HO" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726983AbfKNDvW (ORCPT ); Wed, 13 Nov 2019 22:51:22 -0500 Received: from mail-oi1-f194.google.com ([209.85.167.194]:35519 "EHLO mail-oi1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726393AbfKNDvW (ORCPT ); Wed, 13 Nov 2019 22:51:22 -0500 Received: by mail-oi1-f194.google.com with SMTP id n16so4024998oig.2; Wed, 13 Nov 2019 19:51:21 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=oTNGunsWbSvt43YXzCeF3NH4k2942fdpf8D5q79SgVU=; b=O5PrQ1HOh6MNMvmynIQEo/A6e9bNN8fnEemRDCPzwTzD2yKvWxQKxLng92yJxCvFz/ qXi05MCCH87j5JQIpPBroCsdIw0T+wMw1F4W6xtyxIyibZXGX4Vx90+fj+F2uKv9fiuJ +MUvoVWyZumwU6usy1VABi/N1rqD/m0JhQ8/fPDbN5coQvmDjq5pBoKtvE8MiSeyrDw1 xT+BRZC8evgvljgk6bFkIzNZBmoRGCT92ZJD2GrQWmdtOPYlHozpSaVfERypfl8JuBgu 7n97xgnsyIAwKWVdQXHyGcOZoHV98cymsiscF62QCpLo9sn+g1ltTQGh5ACreFZ9LF0f iuhg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=oTNGunsWbSvt43YXzCeF3NH4k2942fdpf8D5q79SgVU=; b=ouUIkXESd+bwE2060Z5ONd/wUTeTKYUGn8KhtWm3wlTbRyb9Xm/fldWtBgSF3mf5C/ WKhrxNGxmYA4vua0fJR797qQbGwFSSw1tWlYeSHrrzUM4Gk/270ifNFhL+L2xtniM6xn nF7i5A+7nu12e2HV5LSWBQK3KaZ8yZD19VWgBNTAQC5qhXNeorgRLsbwHzPhjxuBfNy3 X4pFCkgvcdndqVhQ5elRA2u0560vubDX4jieYqMaef/E4FkX2U7PyKnCy5g4Qzlj5ePU 1qhEG/s01m+hvTNpoL6XcWQ4/JjjGBBCHPBlyKUU0J+9viZ1zqpQkiCGcySER1bqX2lp My3A== X-Gm-Message-State: APjAAAUZyeBhOJQNcGniZyzjFjWCzsKZetkg1SuPz9eEDjG2Luhj/S/Z DEjTzAB8kOytvrX04lYrhtuYR84DIqBfzKFP/kM= X-Google-Smtp-Source: APXvYqw45OVhkbExH5Ht9xrBIfcFTRS31ZX0p/sarKxNI/uKsFGLBBXd09EfpuoOJZA2zzohS12ILdfi/EdXNrjyqWg= X-Received: by 2002:aca:39d6:: with SMTP id g205mr1735278oia.33.1573703481267; Wed, 13 Nov 2019 19:51:21 -0800 (PST) MIME-Version: 1.0 References: <20191027105243.34339-1-like.xu@linux.intel.com> <20191027105243.34339-6-like.xu@linux.intel.com> In-Reply-To: <20191027105243.34339-6-like.xu@linux.intel.com> From: Wanpeng Li Date: Thu, 14 Nov 2019 11:51:11 +0800 Message-ID: Subject: Re: [PATCH v4 5/6] KVM: x86/vPMU: Reuse perf_event to avoid unnecessary pmc_reprogram_counter To: Like Xu Cc: Peter Zijlstra , Paolo Bonzini , Sean Christopherson , Jim Mattson , Wanpeng Li , Alexander Shishkin , Arnaldo Carvalho de Melo , Borislav Petkov , Ingo Molnar , Jiri Olsa , Joerg Roedel , Namhyung Kim , Thomas Gleixner , Vitaly Kuznetsov , kan.liang@intel.com, wei.w.wang@intel.com, LKML , kvm Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 28 Oct 2019 at 21:06, Like Xu wrote: > > The perf_event_create_kernel_counter() in the pmc_reprogram_counter() is > a heavyweight and high-frequency operation, especially when host disables > the watchdog (maximum 21000000 ns) which leads to an unacceptable latency Why when host disables the watchdog, perf_event_create_kernel_counter() is more heavyweight and high-frequency operation? Wanpeng