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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 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 8E05EC10DCE for ; Fri, 6 Mar 2020 22:34:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6B54320714 for ; Fri, 6 Mar 2020 22:34:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726879AbgCFWeO (ORCPT ); Fri, 6 Mar 2020 17:34:14 -0500 Received: from mail.kernel.org ([198.145.29.99]:47412 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726271AbgCFWeN (ORCPT ); Fri, 6 Mar 2020 17:34:13 -0500 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 250BC206E6; Fri, 6 Mar 2020 22:34:13 +0000 (UTC) Date: Fri, 6 Mar 2020 17:34:11 -0500 From: Steven Rostedt To: "Tzvetomir Stoyanov (VMware)" Cc: linux-trace-devel@vger.kernel.org, Yordan Karadzhov Subject: Re: [PATCH 0/2] KernelShark2.0: Use libtracefs APIs to access tracefs Message-ID: <20200306173411.783cccd0@gandalf.local.home> In-Reply-To: <20200306151356.4bbeef14@gandalf.local.home> References: <20200306092902.48786-1-tz.stoyanov@gmail.com> <20200306151356.4bbeef14@gandalf.local.home> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-trace-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org On Fri, 6 Mar 2020 15:13:56 -0500 Steven Rostedt wrote: > On Fri, 6 Mar 2020 11:29:00 +0200 > "Tzvetomir Stoyanov (VMware)" wrote: > > > From: "Tzvetomir (VMware) Stoyanov" > > > > The tracefs library provides APIs for accessing files from tracefs. > > The library is part of trace-cmd, it is installed as part of trace-cmd > > installation. KernelShark uses some of those APIs and must be linked with > > the library > > > > Tzvetomir (VMware) Stoyanov (2): > > KernelShark2.0: Link KernelShark to libtracefs > > KernelShark2.0: Use libtracefs APIs to access tracefs > > > > I added these patches to the latest kernelshark-2.0 and it still doesn't > work for me. I did a little debugging, and noticed that it fails while > reading the guest trace.dat file with: > > plugin "kvm_combo" failed to initialize on stream /tmp/trace-host-Fedora21. > > It seems to require that the guest trace.dat file has kvm events? > > Note, as I build my guest kernel with a make localmodconfig, which disables > all modules that are not necessary to boot the box, there is no kvm events > there. I can see why the host may need them, but not the guest. I'll > rebuild my guest kernel with kvm events and see if that solves this (but > that shouldn't be the case). > Just confirmed it. If I add kvm events to the guest, it synchronizes automatically. Thus, it's a bug to expect the guest to have kvm events, as there's no reason for them to do so. -- Steve