From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.19]) (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 D5E3D4A1D for ; Mon, 27 Jan 2025 14:41:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.19 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737988878; cv=none; b=jT+u7Fdjclh/iFx0MnZklfQv6DBh32siX7MB1LxBCH0TiF+q87u03O4aoGoRzGNRYHQTwjjkdwTLEJP2P4uhcs7gaDDYXnxuG8T8XonKa7djlPDRAe4XjUVEWGESSiQko2VG+cTIJTParWuj9biPAgQtmxqaEiCW4vW97wydbCA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737988878; c=relaxed/simple; bh=zWJdqNjDoXqh+BlL29YtPiiDirDDgEQ4Kw/Df22vQ4g=; h=Message-ID:Date:MIME-Version:Subject:To:References:From: In-Reply-To:Content-Type; b=AXzkN46MjH0Bu47YFywSLsVIzHtgtRXANY6Wk6D1D3y4mZcRADZ0hIePNl2k1hfAf7zmQuX8KB5gMND7DrKpUdDVmoso2aBTn9rP+67Jo8NeLD2ucUc3KT6wSDBNY+vtyV71PoM4hV+VVTQLZTLtvZsiQYcK2PTbUvxwATBWMOg= 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=T+SMaW/j; arc=none smtp.client-ip=192.198.163.19 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="T+SMaW/j" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1737988876; x=1769524876; h=message-id:date:mime-version:subject:to:references:from: in-reply-to:content-transfer-encoding; bh=zWJdqNjDoXqh+BlL29YtPiiDirDDgEQ4Kw/Df22vQ4g=; b=T+SMaW/jH9EJ9mYN2BxXhi9siPVJfn4drrcdECvxB4/D+Q7gksQaGTiG q4W9qPENCSZj8c9A/mP7hlJppo1Icjz7ucICqXC9EhiqF2B7ectq0dd8T uENRruQ/DGprxNucpKHh5TE7R6AMgkLh7p005kODiHcH6YHGi8ZDZNmlo yvLf8v3eG5lhmE+RxIkidMGThJojP6AQmCXtup3g4iRO6xT8vZ9jF/3fL VaxLZEK7t+X9IHo3t6Oz5vBBTFJOQYr2Gg9NSnzQk1s1pjWobOjhB5E9B zGUaUeXdUQLhKEx+1qP+lCBGgXtcSRcYbv1Q8lLmHgLKFQIuoREKOXuQB g==; X-CSE-ConnectionGUID: h45SRrvbS6G09y5qXMKRRg== X-CSE-MsgGUID: dJoLezfkSU+KOPhBpfmhPw== X-IronPort-AV: E=McAfee;i="6700,10204,11328"; a="37650385" X-IronPort-AV: E=Sophos;i="6.13,238,1732608000"; d="scan'208";a="37650385" Received: from orviesa003.jf.intel.com ([10.64.159.143]) by fmvoesa113.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Jan 2025 06:41:15 -0800 X-CSE-ConnectionGUID: uTb1L5c1RCqxzfsm0qiE7A== X-CSE-MsgGUID: m0qKLiSqRsSqDPkd21sLsQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.11,199,1725346800"; d="scan'208";a="113424545" Received: from linux.intel.com ([10.54.29.200]) by orviesa003.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Jan 2025 06:41:15 -0800 Received: from [10.246.136.10] (kliang2-mobl1.ccr.corp.intel.com [10.246.136.10]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by linux.intel.com (Postfix) with ESMTPS id EBAF120B5713; Mon, 27 Jan 2025 06:41:13 -0800 (PST) Message-ID: <89eb88c8-8c0e-4a43-8ab7-b524be307629@linux.intel.com> Date: Mon, 27 Jan 2025 09:41:12 -0500 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] perf/x86/intel: Clean up PEBS-via-PT on hybrid To: Adrian Hunter , Alexander Shishkin , peterz@infradead.org, mingo@redhat.com, acme@kernel.org, namhyung@kernel.org, irogers@google.com, linux-kernel@vger.kernel.org References: <20250124183432.3565061-1-kan.liang@linux.intel.com> <87y0ywzj7o.fsf@ubik.fi.intel.com> <1954a8b1-83f0-4959-98d3-743662fc7de2@intel.com> Content-Language: en-US From: "Liang, Kan" In-Reply-To: <1954a8b1-83f0-4959-98d3-743662fc7de2@intel.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 2025-01-27 6:42 a.m., Adrian Hunter wrote: > On 27/01/25 11:42, Alexander Shishkin wrote: >> [sending again, because smtp is hard, for some reason] >> kan.liang@linux.intel.com writes: >> >>> From: Kan Liang >>> >>> The PEBS-via-PT feature is exposed for the e-core of some hybrid >>> platforms, e.g., ADL and MTL. But it never works. >>> >>> $ dmesg | grep PEBS >>> [ 1.793888] core: cpu_atom PMU driver: PEBS-via-PT >>> >>> $ perf record -c 1000 -e '{intel_pt/branch=0/, >>> cpu_atom/cpu-cycles,aux-output/pp}' -C8 >>> Error: >>> The sys_perf_event_open() syscall returned with 22 (Invalid argument) >>> for event (cpu_atom/cpu-cycles,aux-output/pp). >>> "dmesg | grep -i perf" may provide additional information. >>> >>> The "PEBS-via-PT" is printed if the corresponding bit of per-PMU >>> capabilities is set. Since the feature is supported by the e-core HW, >>> perf sets the bit for e-core. However, for Intel PT, if a feature is not >>> supported on all CPUs, it is not supported at all. The PEBS-via-PT event >>> cannot be created successfully. >>> >>> The PEBS-via-PT is no longer enumerated on the latest hybrid platform. It >>> will be deprecated on future platforms with Arch PEBS. Let's remove it >>> from the existing hybrid platforms. >> >> There are still lots of them in use in the wild, I'd still like to fix >> this properly instead of chopping it off. Unless there's a reason not to? > > The kernel has never supported PEBS-via-PT on hybrids before. > AFAIK no one is asking for it on hybrids. Right, I didn't get the request on hybrid either. > > Note, it will continue to work on non-hybrid atom/e-core systems > like ADL-N etc > Right, ADL-N and all the non-hybrid still works. It removes the false claim on the hybrid ADL, MTL, RPL, LNL, and Arrow Lake. Thanks, Kan