From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rayson Ho Subject: Tracing KVM with Systemtap Date: Wed, 08 Sep 2010 09:20:30 -0400 Message-ID: <1283952030.2631.19.camel@computer> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit To: kvm@vger.kernel.org Return-path: Received: from mx1.redhat.com ([209.132.183.28]:50837 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757136Ab0IHNU3 (ORCPT ); Wed, 8 Sep 2010 09:20:29 -0400 Received: from int-mx01.intmail.prod.int.phx2.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o88DKTP9007067 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Wed, 8 Sep 2010 09:20:29 -0400 Received: from [10.3.112.20] (ovpn-112-20.phx2.redhat.com [10.3.112.20]) by int-mx01.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id o88DKS5B031238 for ; Wed, 8 Sep 2010 09:20:29 -0400 Sender: kvm-owner@vger.kernel.org List-ID: Hi all, I am a developer of Systemtap. I am looking into tracing KVM (the kernel part and QEMU) and also the KVM guests with Systemtap. I googled and found references to Xenprobes and xdt+dtrace, and I was wondering if someone is working on the dynamic tracing interface for KVM? I've read the KVM kernel code and I think some expensive operations (things that need to be trapped back to the host kernel - eg. loading of control registers on x86/x64) can be interesting spots for adding an SDT (static marker), and I/O operations performed for the guests can be useful information to collect. I know that KVM guests run like a userspace process and thus techniques for tracing Xen might be overkilled, and also gdb can be used to trace KVM guests. However, are that anything special I need to be aware of before I go further into the development of the Systemtap KVM probes? (Opinions / Suggestions / Criticisms welcome!) Thanks, Rayson