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 X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,PLING_QUERY,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 12A21C32789 for ; Tue, 6 Nov 2018 17:26:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DC41F2085B for ; Tue, 6 Nov 2018 17:26:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DC41F2085B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389674AbeKGCwV (ORCPT ); Tue, 6 Nov 2018 21:52:21 -0500 Received: from mga02.intel.com ([134.134.136.20]:45451 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389281AbeKGCwV (ORCPT ); Tue, 6 Nov 2018 21:52:21 -0500 X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 06 Nov 2018 09:26:07 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.54,472,1534834800"; d="scan'208";a="106373460" Received: from tassilo.jf.intel.com (HELO tassilo.localdomain) ([10.7.201.126]) by orsmga002.jf.intel.com with ESMTP; 06 Nov 2018 09:26:07 -0800 Received: by tassilo.localdomain (Postfix, from userid 1000) id B1364301B6D; Tue, 6 Nov 2018 09:26:07 -0800 (PST) Date: Tue, 6 Nov 2018 09:26:07 -0800 From: Andi Kleen To: Jiri Olsa Cc: Milian Wolff , linux-kernel@vger.kernel.org, Jiri Olsa , namhyung@kernel.org, linux-perf-users@vger.kernel.org, Arnaldo Carvalho Subject: Re: PEBS level 2/3 breaks dwarf unwinding! [WAS: Re: Broken dwarf unwinding - wrong stack pointer register value?] Message-ID: <20181106172607.GT6218@tassilo.jf.intel.com> References: <2335309.gnWok9HYb4@agathebauer> <3227038.olIWmsCzzY@agathebauer> <20181105205119.GC25674@krava> <3799078.YBnU1OB0PF@agathebauer> <20181106001037.GQ6218@tassilo.jf.intel.com> <20181106083957.GB8081@krava> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181106083957.GB8081@krava> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > hum, is this about having 'large pebs' or there's this window > if there's also only single pebs record allowed? which should > be case for dwarf unwind With large PEBS today there is never any stack unwind because stack unwinding can be only done from a PMI. The window happens even with single PEBS. It's related to the CPU being pipelined, so complex events may not happen fully atomically. -Andi