From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.14]) (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 3A492131E49 for ; Fri, 4 Sep 2026 00:22:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.14 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788481346; cv=none; b=C3AEGS8gfCZBW4Z8/fWF6E6y14MVii/diL6WtYg5iAE6VI5hFPv130N+oRkb0tssRiSetomE68Y0AwYXWSYcCcqz/JsgLoefeu4/fZPLcGqYxn4yYkBKKXGIQo7KIo6McbTp384wmR8vpUWo+EMWE90xDUmxb+ZCnjL8mAtW/nU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788481346; c=relaxed/simple; bh=canjJ1hDItg2dUA//rbTmSu8Z2w4/pmyKheyAxPz1hQ=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=sbdSFSeK8aJwPeEaji0NcZPvhLr7+amjuTyl0ur7GprlBpBGRRlZJAtQQTVsIUMwm+AdiXPHxkggfOIWC29fDS0VxkEf4KvNv4JGBZddS2A5VJhikhrd4KddoSRKsz8L47Bj4t3XnF8hbqIwvjtrQYgRgldngnE9qhlUZGdcuko= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=EPWOCI6Z; arc=none smtp.client-ip=198.175.65.14 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass 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="EPWOCI6Z" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1788481344; x=1820017344; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=canjJ1hDItg2dUA//rbTmSu8Z2w4/pmyKheyAxPz1hQ=; b=EPWOCI6Z8X+F0KQTuLYzrbGeqjTMAiAwqq0CnZNK/2WeGbUJ0h8FO8ZC ZigOFWJf7m8pMdZlYbq+3RoICgq1zyJBiOnh4MVrUF2Jm7kRrUg6s9lQd YnVRhLB9B37y4w0rWpLz4yB8iwQeSmW7SRQtZ6mdrwZxyBssl8FYXI6T0 bUkq+8RLA8mZdqNwPEjzJIN2RL2VAcOrF+gqQRZwrOtWAXJAPJSogZRl1 ssbcxs6vfCxViPqQiSCIIGlonMrwZskOjlN9g1J0oLlJg7k72XySSt5iz L31VNG/GT5y30go75YyF44JShIwHiMC7rSdaf+hHfogaVUY94zYWt5kfj A==; X-CSE-ConnectionGUID: ghqCLgSHRt+0Tmd7f9njSQ== X-CSE-MsgGUID: PDtgkNPjSm+AZNuojDPJyw== X-IronPort-AV: E=McAfee;i="6800,10657,11895"; a="92851261" X-IronPort-AV: E=Sophos;i="6.25,260,1779174000"; d="scan'208";a="92851261" Received: from orviesa007.jf.intel.com ([10.64.159.147]) by orvoesa106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Sep 2026 17:22:23 -0700 X-CSE-ConnectionGUID: V49YCHLRSgCpMKYpTKZmPw== X-CSE-MsgGUID: HMKh1ARtRN2K/mMBNCUZvQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.25,260,1779174000"; d="scan'208";a="269870819" Received: from dapengmi-mobl1.ccr.corp.intel.com (HELO [10.124.241.239]) ([10.124.241.239]) by orviesa007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Sep 2026 17:22:23 -0700 Message-ID: Date: Fri, 4 Sep 2026 08:22:20 +0800 Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [DISCUSSION] Three problems behind broken "perf --call-graph dwarf" on AMD: IP and stack dump mismatch, libdw fails on lld's layout, and the unwinder fallback never runs To: Ravi Bangoria , Namhyung Kim Cc: Gennady Kupava , linux-perf-users@vger.kernel.org References: <27d79477-c469-413b-95bd-c6c1f8a40f55@amd.com> <7b4cba95-dacc-4cf1-953f-c59e06e693d0@amd.com> <0e5e1fd0-0a46-4c1c-a391-5c245d903834@amd.com> Content-Language: en-US From: "Mi, Dapeng" In-Reply-To: <0e5e1fd0-0a46-4c1c-a391-5c245d903834@amd.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 9/4/2026 12:02 AM, Ravi Bangoria wrote: >> Suppose we need to follow below 2 rules to ensure the correct call-chain >> unwinding and register snapshot consistency. >> >> 1. All registers including IP should come from either PEBS or PMI, must not >> be mixed. This ensures to get an consistent registers snapshot. >> >> 2. Either SAMPLE_CALLCHAIN or SAMPLE_STACK_USER is required, the PMI >> registers snapshot must be used. This proves the correct DWARF unwinding. >> >> How's your idea? > Looks good. Mind sending the patch? Yep, let me cook the patches. Thanks. > > Thanks, > Ravi