Received: by 2002:a05:6a10:a0d1:0:0:0:0 with SMTP id j17csp156091pxa; Fri, 31 Jul 2020 08:39:34 -0700 (PDT) X-Google-Smtp-Source: ABdhPJx02/YwarPO+fQTsB8w/rT8XEPG/8x5+0aWtJKnb7F5x2ctbNXm0qNdEF+p07zF+8JHq35p X-Received: by 2002:a17:906:7787:: with SMTP id s7mr4844298ejm.533.1596209974305; Fri, 31 Jul 2020 08:39:34 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1596209974; cv=none; d=google.com; s=arc-20160816; b=zM/MwCJxX2GMycQO7bVNDmQGt2tlO7NJKN4pe+R4+CVCLbrAwPvRfdWFANU3c66fe1 HoavTCfClNOU9ePqdGvdTIlsbQsyMHsozKxD9jLRTMrG9kZiYvc0QF4rN82ojSuJadmu nbtrnMiSbv1vO+lM+/kB0qFRFQ2FfHR265fAJQYkE0QgeZ2WOc3BdpQBi4mHTxpFBHVO ZQAZEa+baupizmWsf1OTXpfeuoSbHDUJOmbUc4ibBZjPdNmQCuvPq3R4mkgzo4NrGPze eRx+WShfnH/D4dxduxu7dEoiy+XuMHpMk1tX8mUIjPXQkauixzknGo50SurbSxnXIYIw o3Sw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:in-reply-to:content-disposition :mime-version:references:message-id:subject:cc:to:from:date :ironport-sdr:ironport-sdr; bh=gsYDha2ztC0ik8Ek+qRT00oKepDfQdy1cuTD9CxzoCs=; b=zaU0pWjS9lwww51c+nWX/GZg7r0aOQLedXf0h4s1j7MpxGQoKyhfFvsp5Hd1y1wwYH izoS3LPpqybA5PSv0U01SvljVc0WWlGDREOoNNp0/ewgLNJew+XmzDCP1rI/K/njLhcy 1Ki9ahR6VC58bBZPt/R8wX4H6w8FDBdVHkR0426FMYMd6nEgplItPRHR9iXfDHEmtgUx 2RB+aqrd1okOCq2QWKo78Sm4Cf7hJF8XZuK2wdJiPZwpEMc65IRmqH+Nb4LE41BelngG krSlqyOfz5vD2eN8o6tDY3I6ysaCQThUhKY0QEit0NjoJA3fw7TlsncN88qGLWIILbBl C89w== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=intel.com Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id a13si5370058edy.381.2020.07.31.08.39.10; Fri, 31 Jul 2020 08:39:34 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=intel.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728693AbgGaPgV (ORCPT + 99 others); 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