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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BBD75C4332F for ; Mon, 12 Dec 2022 13:23:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232604AbiLLNXU (ORCPT ); Mon, 12 Dec 2022 08:23:20 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49866 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232623AbiLLNXG (ORCPT ); Mon, 12 Dec 2022 08:23:06 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6BFB3C6A; Mon, 12 Dec 2022 05:23:05 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 11146B80B9B; Mon, 12 Dec 2022 13:23:04 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C798CC433D2; Mon, 12 Dec 2022 13:23:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1670851382; bh=p5PQnuuFNi++J1xMQgmtnxT2psOn0oyxKar6oh33zsY=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=nHMNUGwKjZIAtAGoIE24eH6JrcKbP6cviMgEQCvlmly/N6KQ+GYj/8EYdGO6LuTBY OkvfNAr4iiP6zJYu6d+yDY2z30ByhzvfZKhjk0sKG3mAPmSAywcqlLfUTrZor6VNfE YCv7PyDh8EzsOQptXRmhnqeBGWS3bDEr26R6tzSNfk828KhBVCqMAKep1A2lr3tNZ3 EQM1bluHvb2FfhxPvPmdg+j4mF6r/aQp4JUiPK67bNa70UN6Ykvt1A0wwzpV/3XI9N pGIBYcEFoYL6o5ZOq47G8MaeVIXwDfBsyf7Zs42a5/hlItvEeegl4ulLfrnGCU32TI J8o8YFf31IKZw== Received: from sofa.misterjones.org ([185.219.108.64] helo=goblin-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1p4ilo-00C7Oi-IR; Mon, 12 Dec 2022 13:23:00 +0000 Date: Mon, 12 Dec 2022 13:23:00 +0000 Message-ID: <865yegrc23.wl-maz@kernel.org> From: Marc Zyngier To: Like Xu Cc: Peter Zijlstra , Sean Christopherson , Paolo Bonzini , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Fenghua Yu , kvmarm@lists.linux.dev, linux-perf-users@vger.kernel.org Subject: Re: [PATCH RFC 1/8] perf/core: Add *group_leader to perf_event_create_kernel_counter() In-Reply-To: <20221212125844.41157-2-likexu@tencent.com> References: <20221212125844.41157-1-likexu@tencent.com> <20221212125844.41157-2-likexu@tencent.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/27.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: like.xu.linux@gmail.com, peterz@infradead.org, seanjc@google.com, pbonzini@redhat.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, fenghua.yu@intel.com, kvmarm@lists.linux.dev, linux-perf-users@vger.kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Precedence: bulk List-ID: X-Mailing-List: linux-perf-users@vger.kernel.org On Mon, 12 Dec 2022 12:58:37 +0000, Like Xu wrote: > > From: Like Xu > > Like syscalls users, kernel-space perf_event creators may also use group > counters abstraction to gain pmu functionalities, and an in-kernel counter > groups behave much like normal 'single' counters, following the group > semantics-based behavior. > > No functional changes at this time. An example will be that KVM creates > Intel slot event as group leader and other topdown metric events to emulate > MSR_PERF_METRICS pmu capability for guests. > > Cc: Peter Zijlstra > Cc: Marc Zyngier > Cc: Fenghua Yu > Cc: kvmarm@lists.linux.dev > Cc: linux-perf-users@vger.kernel.org > Signed-off-by: Like Xu > --- > arch/arm64/kvm/pmu-emul.c | 4 ++-- > arch/x86/kernel/cpu/resctrl/pseudo_lock.c | 4 ++-- > arch/x86/kvm/pmu.c | 2 +- > arch/x86/kvm/vmx/pmu_intel.c | 2 +- > include/linux/perf_event.h | 1 + > kernel/events/core.c | 4 +++- > kernel/events/hw_breakpoint.c | 4 ++-- > kernel/events/hw_breakpoint_test.c | 2 +- > kernel/watchdog_hld.c | 2 +- > 9 files changed, 14 insertions(+), 11 deletions(-) > > diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c > index 24908400e190..11c3386bc86b 100644 > --- a/arch/arm64/kvm/pmu-emul.c > +++ b/arch/arm64/kvm/pmu-emul.c > @@ -624,7 +624,7 @@ static void kvm_pmu_create_perf_event(struct kvm_pmc *pmc) > > attr.sample_period = compute_period(pmc, kvm_pmu_get_pmc_value(pmc)); > > - event = perf_event_create_kernel_counter(&attr, -1, current, > + event = perf_event_create_kernel_counter(&attr, -1, current, NULL, > kvm_pmu_perf_overflow, pmc); Wouldn't it be better to have a separate helper that takes the group leader as a parameter, and reimplement perf_event_create_kernel_counter() in term of this helper? M. -- Without deviation from the norm, progress is not possible.