From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:46174)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <chao.p.peng@linux.intel.com>) id 1bEstk-0007Bx-HJ
	for qemu-devel@nongnu.org; Mon, 20 Jun 2016 02:41:29 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <chao.p.peng@linux.intel.com>) id 1bEstg-0007iT-Cx
	for qemu-devel@nongnu.org; Mon, 20 Jun 2016 02:41:27 -0400
Received: from mga11.intel.com ([192.55.52.93]:22730)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <chao.p.peng@linux.intel.com>) id 1bEstg-0007iH-7I
	for qemu-devel@nongnu.org; Mon, 20 Jun 2016 02:41:24 -0400
Date: Mon, 20 Jun 2016 14:30:26 +0800
From: Chao Peng <chao.p.peng@linux.intel.com>
Message-ID: <20160620063026.GG21465@pengc-linux.bj.intel.com>
Reply-To: Chao Peng <chao.p.peng@linux.intel.com>
References: <1466151257-96318-1-git-send-email-chao.p.peng@linux.intel.com>
	<576655EF.6010908@huawei.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <576655EF.6010908@huawei.com>
Subject: Re: [Qemu-devel] [RFC 0/9] Introduce light weight PC platform
 pc-lite
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel/>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Claudio Fontana <claudio.fontana@huawei.com>
Cc: qemu-devel@nongnu.org, Haozhong Zhang <haozhong.zhang@intel.com>, Xiao Guangrong <guangrong.xiao@linux.intel.com>, Eduardo Habkost <ehabkost@redhat.com>, "Michael S. Tsirkin" <mst@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>, gor Mammedov <imammedo@redhat.com>, Richard Henderson <rth@twiddle.net>

> 
> The combination of devices removed/supported seems a bit arbitrary to me.
> The use in this text of "legacy" and non-"legacy" is also arbitrary if not given a definition.

The criterial here is to remove the devices that have poor performance.
You can think legacy devices here as ISA devices. Most of them are
emulated with slow port IO and slow line-based IRQ handling.

> 
> What is the use case of this new platform?

You can have a look at Clear containers
(https://clearlinux.org/features/clear-containers) or other similar
technologies. Basically they try to provide container-like service with
VT to improve security. Clear containers employ kvm-tool to gain 'lite'
benefit. This patch however try to achive the same with QEMU.

> 
> Care to share your numbers about how FAST is FAST? Like how much time you need to boot from qemu launch to the guest being booted, and on which hardware, and which guest kernel configuration?

Kernel .config is already listed in the repo I listed below. For
guest kernel and BIOS performance data please see another reply to mst.
QEMU bootup time itself however is mainly not improved with this
patchset, but the optmized QEMU normally we see takes ~45ms.

Thanks,
Chao

> 
> Ciao,
> 
> Claudio
> 
> > 
> > Please follow https://github.com/chao-p/qemu-lite-tools.
> > 
> > Thanks,
> > Chao