From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:54751) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1R0yC4-0007fg-32 for qemu-devel@nongnu.org; Tue, 06 Sep 2011 12:08:17 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1R0yC0-0001bR-0f for qemu-devel@nongnu.org; Tue, 06 Sep 2011 12:08:12 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39717) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1R0yBz-0001bL-L3 for qemu-devel@nongnu.org; Tue, 06 Sep 2011 12:08:07 -0400 Date: Tue, 6 Sep 2011 19:09:04 +0300 From: "Michael S. Tsirkin" Message-ID: <20110906160903.GA21675@redhat.com> References: <20110906144828.GA20834@redhat.com> <4E66402C.2020900@siemens.com> <4E66417E.6040308@codemonkey.ws> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4E66417E.6040308@codemonkey.ws> Subject: Re: [Qemu-devel] [PATCH 0/6] Device state visualization reloaded List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anthony Liguori Cc: Jan Kiszka , Anthony Liguori , qemu-devel , Markus Armbruster , Luiz Capitulino On Tue, Sep 06, 2011 at 10:51:26AM -0500, Anthony Liguori wrote: > On 09/06/2011 10:45 AM, Jan Kiszka wrote: > >On 2011-09-06 16:48, Michael S. Tsirkin wrote: > >>I'm afraid that won't be enough to stop people > >>scripting this command - libvirt accessed > >>HMP for years. > >> > >>On the other hand, no QMP command means e.g. > >>libvirt users don't get any benefit from this. > >> > >>What I think will solve these problems, for both HMP and QMP, > >>is an explicit 'debug_unstable' or 'debug_unsupported' command that will > >>expose all kind of debugging functionality making it > >>very explicit that it's an unsupported debugging utility. > >> > >>Proposed syntax: > >> > >>debug_unstable > >> > >>Example: > >> > >>debug_unstable device_show -all > > > >For HMP, this would needlessly complicate the user interface, nothing I > >would support. People scripting things on top of HMP are generally doing > >this on their own risk and cannot expect output stability. > > > >device_show is like info qtree: the output will naturally change as the > >emulated hardware evolves, information is added/removed, or we simply > >improve the layout. Recent changes on info network are an example for > >the latter. > > Yeah, I'm not worried about stability. HMP commands that aren't > exposed as QMP commands are inherently unstable and should not be > scripted to. They are also not accessible when using libvirt, right? Which means almost all cases I care about: debugging on my laptop I can easily attach with gdb and inspect state. > I'm still contemplating how we go about doing this. This series > introduces a couple new concepts like QMP class hinting anonymous > IDs. I'm concerned that we'll further complicate the need to support > backwards compatibility. Dazed and confused. Above you stated these commands are inherently unstable and no need to support? > Would the command be useful if you couldn't address devices? If it > just dumped the full machine state all at once? That would at least > obviate the need to add anonymous IDs. > > Regards, > > Anthony Liguori > > > > >Jan > >