From mboxrd@z Thu Jan  1 00:00:00 1970
From: Stefan Hajnoczi <stefanha@gmail.com>
Subject: Re: Tracing KVM with Systemtap
Date: Tue, 21 Sep 2010 14:33:53 +0100
Message-ID: <AANLkTimyTLoBt8mCdEDJWmCFycKUW8DSN+K=z39LYF_T@mail.gmail.com>
References: <1283952030.2631.19.camel@computer>
	<AANLkTimbrDwhHOZxWiWhzKQgt=yq6N7GWkGHtJK3sHSR@mail.gmail.com>
	<1284988762.2500.13.camel@computer>
	<AANLkTikr3eRT27r9w23_G89oxrMDhtukW4vN9UUhuMwH@mail.gmail.com>
	<1285073887.2566.39.camel@computer>
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: QUOTED-PRINTABLE
Cc: kvm@vger.kernel.org, systemtap@sources.redhat.com,
	Prerna Saxena <prerna@linux.vnet.ibm.com>
To: Rayson Ho <rho@redhat.com>
Return-path: <kvm-owner@vger.kernel.org>
Received: from mail-pz0-f46.google.com ([209.85.210.46]:59137 "EHLO
	mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1752030Ab0IUNdy convert rfc822-to-8bit (ORCPT
	<rfc822;kvm@vger.kernel.org>); Tue, 21 Sep 2010 09:33:54 -0400
Received: by mail-pz0-f46.google.com with SMTP id 34so1409163pzk.19
        for <kvm@vger.kernel.org>; Tue, 21 Sep 2010 06:33:54 -0700 (PDT)
In-Reply-To: <1285073887.2566.39.camel@computer>
Sender: kvm-owner@vger.kernel.org
List-ID: <kvm.vger.kernel.org>

On Tue, Sep 21, 2010 at 1:58 PM, Rayson Ho <rho@redhat.com> wrote:
> On Mon, 2010-09-20 at 14:36 +0100, Stefan Hajnoczi wrote:
>> Right now there are few pre-defined probes ("trace events" in QEMU
>> tracing speak). =A0As I develop I try to be mindful of new ones I cr=
eate
>> and whether they would be generally useful. =A0I intend to contribut=
e
>> more probes and hope others will too!
>
> I am still looking at/hacking the QEMU code. I have looked at the
> following places in the code that I think can be useful to have
> statistics gathered:
>
> net.c qemu_deliver_packet(), etc - network statistics

Yes.

> <CPU Arch>/op_helper.c global_cpu_lock(), tlb_fill() - lock & unlock,
> and TLB refill statistics

These are not relevant to KVM, they are only used when running with
KVM disabled (TCG mode).

> balloon.c, hw/virtio-balloon.c - ballooning information.

Prerna added a balloon event which is in qemu.git trace-events.  Does
that one do what you need?

> I will see what other probes are useful for the end users. Also, are
> there developer documentations for KVM? (I googled but found a lot of
> presentations about KVM but not a lot of info about the internals.)

Not really.  I suggest grabbing the source and following vl.c:main()
to the main KVM execution code.

Stefan