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From: "Michael S. Tsirkin" <mst@redhat.com>
To: Zha Bin <zhabin@linux.alibaba.com>
Cc: linux-kernel@vger.kernel.org, jasowang@redhat.com,
	slp@redhat.com, virtio-dev@lists.oasis-open.org,
	qemu-devel@nongnu.org, gerry@linux.alibaba.com,
	jing2.liu@linux.intel.com, chao.p.peng@linux.intel.com
Subject: Re: [PATCH v2 0/5] virtio mmio specification enhancement
Date: Mon, 10 Feb 2020 06:44:50 -0500	[thread overview]
Message-ID: <20200210062938-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <cover.1581305609.git.zhabin@linux.alibaba.com>

On Mon, Feb 10, 2020 at 05:05:16PM +0800, Zha Bin wrote:
> We have compared the number of files and the lines of code between
> virtio-mmio and virio-pci.
> 
> 				Virtio-PCI	    Virtio-MMIO	
> 	number of files(Linux)	    161			1
> 	lines of code(Linux)	    78237		538



Something's very wrong here. virtio PCI is 161 files?
Are you counting the whole PCI subsystem?
Sure enough:

$ find drivers/pci -name '*c' |wc -l
150

That's not reasonable, this includes a bunch of drivers that
never run on a typical hypervisor.

MMIO is also not as small as you are trying to show:

$ cloc drivers/virtio/virtio_mmio.c include/uapi/linux/virtio_mmio.h
       2 text files.
       2 unique files.                              
       0 files ignored.

github.com/AlDanial/cloc v 1.82  T=0.01 s (230.7 files/s, 106126.5 lines/s)
-------------------------------------------------------------------------------
Language                     files          blank        comment           code
-------------------------------------------------------------------------------
C                                1            144            100            535
C/C++ Header                     1             39             66             36
-------------------------------------------------------------------------------
SUM:                             2            183            166            571
-------------------------------------------------------------------------------


I don't doubt MMIO is smaller than PCI. Of course that's because it has
no features to speak of - just this patch already doubles it's size. If
we keep doing that because we want the features then they will reach
the same size in about 4 iterations.


-- 
MST


  parent reply	other threads:[~2020-02-10 11:45 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-10  9:05 Zha Bin
2020-02-10  9:05 ` [PATCH v2 1/5] virtio-mmio: add notify feature for per-queue Zha Bin
2020-02-11 10:50   ` Michael S. Tsirkin
2020-02-11 11:33   ` Michael S. Tsirkin
2020-02-12  3:39     ` Jason Wang
2020-02-12  8:18       ` Michael S. Tsirkin
2020-02-12  8:53         ` Jason Wang
2020-02-12  9:33           ` Jason Wang
2020-02-12  9:55             ` Michael S. Tsirkin
2020-02-13  3:38               ` Jason Wang
2020-02-10  9:05 ` [PATCH v2 2/5] virtio-mmio: refactor common functionality Zha Bin
2020-02-11 11:19   ` Michael S. Tsirkin
2020-02-12  2:58     ` [virtio-dev] " Liu, Jing2
2020-02-12  7:29       ` Michael S. Tsirkin
2020-02-10  9:05 ` [PATCH v2 3/5] virtio-mmio: create a generic MSI irq domain Zha Bin
2020-02-11 11:16   ` Michael S. Tsirkin
2020-02-12  7:40   ` Michael S. Tsirkin
2020-02-10  9:05 ` [PATCH v2 4/5] virtio-mmio: add MSI interrupt feature support Zha Bin
2020-02-11  3:17   ` Jason Wang
2020-02-11  3:35     ` [virtio-dev] " Liu, Jing2
2020-02-11  4:02       ` Jason Wang
     [not found]         ` <5522f205-207b-b012-6631-3cc77dde3bfe@linux.intel.com>
2020-02-11  7:40           ` Jason Wang
2020-02-11 11:58             ` Michael S. Tsirkin
2020-02-11 12:04               ` Jason Wang
2020-02-11 12:08                 ` Michael S. Tsirkin
2020-02-11 12:18                   ` Jason Wang
2020-02-11 14:00                     ` Michael S. Tsirkin
2020-02-12  9:03                       ` Jason Wang
2020-02-12  9:15                         ` Michael S. Tsirkin
     [not found]             ` <4c19292f-9d25-a859-3dde-6dd5a03fdf0b@linux.intel.com>
2020-02-12  7:33               ` Michael S. Tsirkin
2020-02-12  9:06               ` Jason Wang
2020-02-12  9:16                 ` Michael S. Tsirkin
2020-02-13  3:40                   ` Jason Wang
2020-02-11 11:21       ` Michael S. Tsirkin
2020-02-11 11:11   ` Michael S. Tsirkin
2020-02-10  9:05 ` [PATCH v2 5/5] x86: virtio-mmio: support virtio-mmio with MSI for x86 Zha Bin
2020-02-11 11:14   ` Michael S. Tsirkin
2020-02-10 11:44 ` Michael S. Tsirkin [this message]
2020-02-11 16:05   ` [PATCH v2 0/5] virtio mmio specification enhancement Chao Peng
2020-02-11 10:57     ` Michael S. Tsirkin
     [not found] <DM6PR11MB4331B490586462DE7353E0B8F9710@DM6PR11MB4331.namprd11.prod.outlook.com>
2020-07-31 10:13 ` Stefan Hajnoczi
2020-07-31 15:44 ` Alex Bennée
2020-08-03 16:19   ` Alex Bennée
2020-08-03 23:31   ` Pincus, Josh

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