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=-4.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 8AF57C433E0 for ; Fri, 31 Jul 2020 15:36:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6BAE220663 for ; Fri, 31 Jul 2020 15:36:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732493AbgGaPgV (ORCPT ); Fri, 31 Jul 2020 11:36:21 -0400 Received: from mga17.intel.com ([192.55.52.151]:58807 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726502AbgGaPgV (ORCPT ); Fri, 31 Jul 2020 11:36:21 -0400 IronPort-SDR: V3cy9WAI8puyK3+OkldWG3Iu9i11voRI5QXwgVHe25fBZ+PnV8HzSmOG5AYIwPCqvb6m+B1Zhr vlSl6zO83/SQ== X-IronPort-AV: E=McAfee;i="6000,8403,9698"; a="131870105" X-IronPort-AV: E=Sophos;i="5.75,418,1589266800"; d="scan'208";a="131870105" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 31 Jul 2020 08:36:12 -0700 IronPort-SDR: XgET9NixUnhaT4TLYpyY7GHa6ma0MltRBq6C3EiuEBzw7UkyxjJ/AqamIateYupWukx4sYy5RD KLX38t/RCaxQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.75,418,1589266800"; d="scan'208";a="331094744" Received: from tassilo.jf.intel.com (HELO tassilo.localdomain) ([10.7.201.21]) by orsmga007.jf.intel.com with ESMTP; 31 Jul 2020 08:36:12 -0700 Received: by tassilo.localdomain (Postfix, from userid 1000) id 53F30301C02; Fri, 31 Jul 2020 08:36:12 -0700 (PDT) Date: Fri, 31 Jul 2020 08:36:12 -0700 From: Andi Kleen To: Jiri Olsa Cc: David Ahern , peterz@infradead.org, Jiri Olsa , Arnaldo Carvalho de Melo , lkml , Ingo Molnar , Namhyung Kim , Alexander Shishkin , Michael Petlan , Ian Rogers , =?iso-8859-1?Q?Genevi=E8ve?= Bastien , Wang Nan , Jeremie Galarneau Subject: Re: [PATCH 0/6] perf tools: Add wallclock time conversion support Message-ID: <20200731153612.GC1299820@tassilo.jf.intel.com> References: <20200730213950.1503773-1-jolsa@kernel.org> <20200730221423.GH2638@hirez.programming.kicks-ass.net> <20200731074726.GA1485940@krava> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200731074726.GA1485940@krava> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > yep, we have a customer that needs to compare data from multiple servers It's also needed to correlate over different guests on the same machine. This is an important use case. It would be nice if we could find a way to export the per guest TSC offset from KVM, then we could use the more reliable TSC for this, at least as long as no TSC scaling is used. But failing that wall clock is probably the best you can do. -Andi