From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.16]) (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 AC3DE1624C5; Wed, 20 Aug 2025 05:54:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.16 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755669265; cv=none; b=RcGT8/f2FYICkDYgL8LGWmsfGMoMRmkdWxASWE00Pj8cy4SYEfUCbHcfCCWoAKqXX8HUm/k5wjBMHRMLxuvyiGPJ/LxWdzR2ho8xL7HJxhvabGziwB7uW1exqv69xhA1E4qZlGV+9+w1GcUVSL3ZROSdt5Hhi9Nav9InzY3VNnE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755669265; c=relaxed/simple; bh=IaIJ+rusFPu7AQeJZSbdYkBlqREjoLUKiBlYhFsnFNI=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=n1SNbhG8FMZFPy4V9JMBDFkTeu0ad/Gjy1LnEtQ3PdzWOP+hcydz6bKHjdpA6XSvxfEUEoMWLZJ73SCWFW2ISxFei46uWzf+UGpt243BqY/l6LXRMsz7GC3whf+hSD6yZO+4ZYBnZo0/92JL4RoXTYgD05vNRM4PbjD4WzWhz5k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=EjJo0lSQ; arc=none smtp.client-ip=198.175.65.16 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="EjJo0lSQ" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1755669264; x=1787205264; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=IaIJ+rusFPu7AQeJZSbdYkBlqREjoLUKiBlYhFsnFNI=; b=EjJo0lSQCDvJ649ncHRBcgUCP4nbPJNGRdhoANMV/KX4UGu8iYTGZjt+ 5gsaTN8xvVNYLregRgDSEzeZx0lvLVY0GHNTEhxxidNRFDoyshOWClXux MBI1MadMIcUZKh5+erDLx9F3RBNcs+egSHWAI5a4jCuuMswMNDNetyvuC GpEL5qtmdlJnEZWG9henJKZ2zl4zo4Nj1DPqyBL1VO9D9NJAUb2kL3Lhr x2R2ii1bSbR9H7atPbyOE943/UK9eC2p0dxDj9SnKlL3q8WAVa+YEMuVI yZy+nlD4jnOPlsLTIsVfNnIjwo6PPQTuVMPlC9bxcyIwKasUeNXdgzxeP w==; X-CSE-ConnectionGUID: a84xeYGWSy2NUgPR+nTTsA== X-CSE-MsgGUID: CUP1LzUPSDqAukuMQ8pMCw== X-IronPort-AV: E=McAfee;i="6800,10657,11527"; a="58076084" X-IronPort-AV: E=Sophos;i="6.17,302,1747724400"; d="scan'208";a="58076084" Received: from fmviesa007.fm.intel.com ([10.60.135.147]) by orvoesa108.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Aug 2025 22:54:23 -0700 X-CSE-ConnectionGUID: oT8Rtm0jSIaq7gWObcSqKQ== X-CSE-MsgGUID: QAcufMB/RVCZKRdyFWK2NA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.17,302,1747724400"; d="scan'208";a="167543502" Received: from dapengmi-mobl1.ccr.corp.intel.com (HELO [10.124.240.36]) ([10.124.240.36]) by fmviesa007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Aug 2025 22:54:20 -0700 Message-ID: Date: Wed, 20 Aug 2025 13:54:17 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [Patch v3 3/7] perf/x86: Check if cpuc->events[*] pointer exists before accessing it To: Andi Kleen Cc: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Ian Rogers , Adrian Hunter , Alexander Shishkin , Kan Liang , Eranian Stephane , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Dapeng Mi , kernel test robot References: <20250820023032.17128-1-dapeng1.mi@linux.intel.com> <20250820023032.17128-4-dapeng1.mi@linux.intel.com> Content-Language: en-US From: "Mi, Dapeng" In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 8/20/2025 1:44 PM, Andi Kleen wrote: >> Andi, I didn't fully get the exact meaning about the "log" here. When >> throttle is triggered, perf_event_throttle() has already called >> perf_log_throttle() to log the throttle event although only for the group >> leader. Is it enough? > Throttle normally doesn't involve data loss, just less samples. But this > is data loss, so it's an overflow. IIUC, there should be no data loss, the unprocessed PEBS records of these throttled events would be still processed eventually by calling intel_pmu_drain_pebs_buffer() when stopping the event. > > -Andi >