From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 64FFC48A2A1; Tue, 9 Jun 2026 15:48:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.92.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781020115; cv=none; b=q2jF6ixRR38bEXbEtcNg8rdWDzqEovlvgVcdHAZAe7bjp3j58EQl/WY4+wGgSor5O1uQk9e+RByQbvK1VSKRe3IgIcMQMQLdgCLly5r0nKmOstC3piSEfEw2qv/55tsGqcIpMhvo7U7K0d0Wu0J9xlYc0nF3fLexdUDA6DOU5Uk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781020115; c=relaxed/simple; bh=ImnIoee5onDHjrcTFYmtQJvmJotODJPtHB+sKhkNym0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=mBVLKXCPaX6VF3+byPVJDVcyXJCMZvA0kiXLVPCZEMWhGxG5A6aYn+A5wrRMMCTz8g2aC2/bLxRiQwDdtbaYg6IhzfqaN9+M0DDn5bQSB7sxbejDtQTeT8OWjjzYdLh2iZBSdfVrVbW/9TT6h5r1EV94jzNR1VwigQ4MOTgYHzY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=pass smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=ZbQwY9r9; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="ZbQwY9r9" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=89kaOsICHrLAJhB1g6xne0LAEm5RZWANfXlE1A7ejgY=; b=ZbQwY9r9XhTTWb4wW3PAOMCTf7 mQNmO3+jZEuefsY7Op1XuSPVHgT8lfUDlNccfgZcoCPOtxxtJFeu2dy0eZ4sJz15WbYM9zILFV/EO PRGnT4exa+Q9gf2jTDEmz3iLJUGT/IooUGjgPDND0RBKwbjuYwY/W7jZhCTZyvoSueZuAScloHByP 2asRINfQ7M21OHJAwTw1YkeJ9MgOz38tiTPOqpdy2zmj+Ei1/f3G1KuvJALQJqXBDRxeJM46P66UY Jkjf/N3d49l8ZfGi4XvUUBR5Y8E376MPc8ODcX8iceQ9IuzM3VYyR5ojF2EBQSqK1SjIrqok5+yUD k7aU6wUQ==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.99.2 #2 (Red Hat Linux)) id 1wWxkT-00000002g5N-3qko; Tue, 09 Jun 2026 14:48:14 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 516E2302F12; Tue, 09 Jun 2026 16:48:12 +0200 (CEST) Date: Tue, 9 Jun 2026 16:48:12 +0200 From: Peter Zijlstra To: Dapeng Mi Cc: Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Ian Rogers , Adrian Hunter , Alexander Shishkin , Andi Kleen , Eranian Stephane , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Dapeng Mi , Zide Chen , Falcon Thomas , Xudong Hao Subject: Re: [Patch v2 3/9] perf/x86: Update cap_user_rdpmc base on rdpmc user disable state Message-ID: <20260609144812.GB49951@noisy.programming.kicks-ass.net> References: <20260609050222.2458129-1-dapeng1.mi@linux.intel.com> <20260609050222.2458129-4-dapeng1.mi@linux.intel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260609050222.2458129-4-dapeng1.mi@linux.intel.com> On Tue, Jun 09, 2026 at 01:02:16PM +0800, Dapeng Mi wrote: > diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c > index 3bd0522afe6d..6cd95b8e31cb 100644 > --- a/arch/x86/events/core.c > +++ b/arch/x86/events/core.c > @@ -2797,6 +2797,9 @@ void arch_perf_update_userpage(struct perf_event *event, > userpg->cap_user_time_zero = 0; > userpg->cap_user_rdpmc = > !!(event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT); > + if (x86_pmu_has_rdpmc_user_disable(event->pmu) && > + event->hw.config & ARCH_PERFMON_EVENTSEL_RDPMC_USER_DISABLE) > + userpg->cap_user_rdpmc = 0; > userpg->pmc_width = x86_pmu.cntval_bits; > > if (!using_native_sched_clock() || !sched_clock_stable()) Remember, this is evaluated very very often. So it makes more sense to ensure the hw.flags state is correct such that this remains a simple expression.