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From: Yan Zhao <yan.y.zhao@intel.com>
To: Sean Mooney <smooney@redhat.com>
Cc: "Cornelia Huck" <cohuck@redhat.com>,
	"Daniel P. Berrangé" <berrange@redhat.com>,
	kvm@vger.kernel.org, libvir-list@redhat.com,
	"Jason Wang" <jasowang@redhat.com>,
	qemu-devel@nongnu.org, kwankhede@nvidia.com, eauger@redhat.com,
	xin-ran.wang@intel.com, corbet@lwn.net,
	openstack-discuss@lists.openstack.org, shaohe.feng@intel.com,
	kevin.tian@intel.com, "Parav Pandit" <parav@mellanox.com>,
	jian-feng.ding@intel.com, dgilbert@redhat.com,
	zhenyuw@linux.intel.com, hejie.xu@intel.com,
	bao.yumeng@zte.com.cn,
	"Alex Williamson" <alex.williamson@redhat.com>,
	intel-gvt-dev@lists.freedesktop.org, eskultet@redhat.com,
	"Jiri Pirko" <jiri@mellanox.com>,
	dinechin@redhat.com, devel@ovirt.org
Subject: Re: device compatibility interface for live migration with assigned devices
Date: Thu, 20 Aug 2020 12:01:16 +0800	[thread overview]
Message-ID: <20200820040116.GB24121@joy-OptiPlex-7040> (raw)
In-Reply-To: <242591bb809b68c618f62fdc93d4f8ae7b146b6d.camel@redhat.com>

On Thu, Aug 20, 2020 at 02:29:07AM +0100, Sean Mooney wrote:
> On Thu, 2020-08-20 at 08:39 +0800, Yan Zhao wrote:
> > On Tue, Aug 18, 2020 at 11:36:52AM +0200, Cornelia Huck wrote:
> > > On Tue, 18 Aug 2020 10:16:28 +0100
> > > Daniel P. Berrangé <berrange@redhat.com> wrote:
> > > 
> > > > On Tue, Aug 18, 2020 at 05:01:51PM +0800, Jason Wang wrote:
> > > > >    On 2020/8/18 下午4:55, Daniel P. Berrangé wrote:
> > > > > 
> > > > >  On Tue, Aug 18, 2020 at 11:24:30AM +0800, Jason Wang wrote:
> > > > > 
> > > > >  On 2020/8/14 下午1:16, Yan Zhao wrote:
> > > > > 
> > > > >  On Thu, Aug 13, 2020 at 12:24:50PM +0800, Jason Wang wrote:
> > > > > 
> > > > >  On 2020/8/10 下午3:46, Yan Zhao wrote:  
> > > > >  we actually can also retrieve the same information through sysfs, .e.g
> > > > > 
> > > > >  |- [path to device]
> > > > >     |--- migration
> > > > >     |     |--- self
> > > > >     |     |   |---device_api
> > > > >     |    |   |---mdev_type
> > > > >     |    |   |---software_version
> > > > >     |    |   |---device_id
> > > > >     |    |   |---aggregator
> > > > >     |     |--- compatible
> > > > >     |     |   |---device_api
> > > > >     |    |   |---mdev_type
> > > > >     |    |   |---software_version
> > > > >     |    |   |---device_id
> > > > >     |    |   |---aggregator
> > > > > 
> > > > > 
> > > > >  Yes but:
> > > > > 
> > > > >  - You need one file per attribute (one syscall for one attribute)
> > > > >  - Attribute is coupled with kobject
> > > 
> > > Is that really that bad? You have the device with an embedded kobject
> > > anyway, and you can just put things into an attribute group?
> > > 
> > > [Also, I think that self/compatible split in the example makes things
> > > needlessly complex. Shouldn't semantic versioning and matching already
> > > cover nearly everything? I would expect very few cases that are more
> > > complex than that. Maybe the aggregation stuff, but I don't think we
> > > need that self/compatible split for that, either.]
> > 
> > Hi Cornelia,
> > 
> > The reason I want to declare compatible list of attributes is that
> > sometimes it's not a simple 1:1 matching of source attributes and target attributes
> > as I demonstrated below,
> > source mdev of (mdev_type i915-GVTg_V5_2 + aggregator 1) is compatible to
> > target mdev of (mdev_type i915-GVTg_V5_4 + aggregator 2),
> >                (mdev_type i915-GVTg_V5_8 + aggregator 4)
> the way you are doing the nameing is till really confusing by the way
> if this has not already been merged in the kernel can you chagne the mdev
> so that mdev_type i915-GVTg_V5_2 is 2 of mdev_type i915-GVTg_V5_1 instead of half the device
> 
> currently you need to deived the aggratod by the number at the end of the mdev type to figure out
> how much of the phsicial device is being used with is a very unfridly api convention
> 
> the way aggrator are being proposed in general is not really someting i like but i thin this at least
> is something that should be able to correct.
> 
> with the complexity in the mdev type name + aggrator i suspect that this will never be support
> in openstack nova directly requireing integration via cyborg unless we can pre partion the
> device in to mdevs staicaly and just ignore this.
> 
> this is way to vendor sepecif to integrate into something like openstack in nova unless we can guarentee
> taht how aggreator work will be portable across vendors genericly.
> 
> > 
> > and aggragator may be just one of such examples that 1:1 matching does not
> > fit.
> for openstack nova i dont see us support anything beyond the 1:1 case where the mdev type does not change.
>
hi Sean,
I understand it's hard for openstack. but 1:N is always meaningful.
e.g.
if source device 1 has cap A, it is compatible to
device 2: cap A,
device 3: cap A+B,
device 4: cap A+B+C
....
to allow openstack to detect it correctly, in compatible list of
device 2, we would say compatible cap is A;
device 3, compatible cap is A or A+B;
device 4, compatible cap is A or A+B, or A+B+C;

then if openstack finds device A's self cap A is contained in compatible
cap of device 2/3/4, it can migrate device 1 to device 2,3,4.

conversely,  device 1's compatible cap is only A,
so it is able to migrate device 2 to device 1, and it is not able to
migrate device 3/4 to device 1.

Thanks
Yan

> i woudl really prefer if there was just one mdev type that repsented the minimal allcatable unit and the
> aggragaotr where used to create compostions of that. i.e instad of i915-GVTg_V5_2 beign half the device,
> have 1 mdev type i915-GVTg and if the device support 8 of them then we can aggrate 4 of i915-GVTg
> 
> if you want to have muplie mdev type to model the different amoutn of the resouce e.g. i915-GVTg_small i915-GVTg_large
> that is totlaly fine too or even i915-GVTg_4 indcating it sis 4 of i915-GVTg
> 
> failing that i would just expose an mdev type per composable resouce and allow us to compose them a the user level with
> some other construct mudeling a attament to the device. e.g. create composed mdev or somethig that is an aggreateion of
> multiple sub resouces each of which is an mdev. so kind of like how bond port work. we would create an mdev for each of
> the sub resouces and then create a bond or aggrated mdev by reference the other mdevs by uuid then attach only the
> aggreated mdev to the instance.
> 
> the current aggrator syntax and sematic however make me rather uncofrotable when i think about orchestating vms on top
> of it even to boot them let alone migrate them.
> > 
> > So, we explicitly list out self/compatible attributes, and management
> > tools only need to check if self attributes is contained compatible
> > attributes.
> > 
> > or do you mean only compatible list is enough, and the management tools
> > need to find out self list by themselves?
> > But I think provide a self list is easier for management tools.
> > 
> > Thanks
> > Yan
> > 
> 

  reply	other threads:[~2020-08-20  4:17 UTC|newest]

Thread overview: 114+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-13 23:29 device compatibility interface for live migration with assigned devices Yan Zhao
2020-07-14 10:21 ` Daniel P. Berrangé
2020-07-14 12:33   ` Sean Mooney
     [not found]     ` <20200714110148.0471c03c@x1.home>
     [not found]       ` <eb705c72cdc8b6b8959b6ebaeeac6069a718d524.camel@redhat.com>
2020-07-14 21:15         ` Sean Mooney
2020-07-14 16:16   ` Alex Williamson
2020-07-14 16:47     ` Daniel P. Berrangé
2020-07-14 20:47       ` Alex Williamson
2020-07-15  9:16         ` Daniel P. Berrangé
2020-07-14 17:19     ` Dr. David Alan Gilbert
2020-07-14 20:59       ` Alex Williamson
2020-07-15  8:20         ` Yan Zhao
2020-07-15  8:49           ` Feng, Shaohe
2020-07-17 14:59           ` Alex Williamson
2020-07-17 18:03             ` Dr. David Alan Gilbert
2020-07-17 18:30               ` Alex Williamson
2020-07-15  8:23         ` Dr. David Alan Gilbert
     [not found]         ` <CAH7mGatPWsczh_rbVhx4a+psJXvkZgKou3r5HrEQTqE7SqZkKA@mail.gmail.com>
2020-07-17 15:18           ` Alex Williamson
2020-07-16  4:16 ` Jason Wang
2020-07-16  8:32   ` Yan Zhao
2020-07-16  9:30     ` Jason Wang
2020-07-17 16:12     ` Alex Williamson
2020-07-20  3:41       ` Jason Wang
2020-07-20 10:39         ` Sean Mooney
2020-07-21  2:11           ` Jason Wang
2020-07-21  0:51       ` Yan Zhao
2020-07-27  7:24         ` Yan Zhao
2020-07-27 22:23           ` Alex Williamson
2020-07-29  8:05             ` Yan Zhao
2020-07-29 11:28               ` Sean Mooney
2020-07-29 19:12                 ` Alex Williamson
2020-07-30  3:41                   ` Yan Zhao
2020-07-30 13:24                     ` Sean Mooney
2020-07-30 17:29                     ` Alex Williamson
2020-08-04  8:37                       ` Yan Zhao
2020-08-05  9:44                         ` Dr. David Alan Gilbert
2020-07-30  1:56                 ` Yan Zhao
2020-07-30 13:14                   ` Sean Mooney
2020-08-04 16:35               ` Cornelia Huck
2020-08-05  2:22                 ` Jason Wang
2020-08-05  2:16                   ` Yan Zhao
2020-08-05  2:41                     ` Jason Wang
2020-08-05  7:56                       ` Jiri Pirko
2020-08-05  8:02                         ` Jason Wang
2020-08-05  9:33                           ` Yan Zhao
2020-08-05 10:53                             ` Jiri Pirko
2020-08-05 11:35                               ` Sean Mooney
2020-08-07 11:59                                 ` Cornelia Huck
2020-08-13 15:33                                   ` Cornelia Huck
2020-08-13 19:02                                     ` Eric Farman
2020-08-17  6:38                                       ` Cornelia Huck
2020-08-10  7:46                               ` Yan Zhao
2020-08-13  4:24                                 ` Jason Wang
2020-08-14  5:16                                   ` Yan Zhao
2020-08-14 12:30                                     ` Sean Mooney
2020-08-17  1:52                                       ` Yan Zhao
2020-08-18  3:24                                     ` Jason Wang
2020-08-18  8:55                                       ` Daniel P. Berrangé
2020-08-18  9:06                                         ` Cornelia Huck
2020-08-18  9:24                                           ` Daniel P. Berrangé
2020-08-18  9:38                                             ` Cornelia Huck
     [not found]                                         ` <3a073222-dcfe-c02d-198b-29f6a507b2e1@redhat.com>
2020-08-18  9:16                                           ` Daniel P. Berrangé
2020-08-18  9:36                                             ` Cornelia Huck
2020-08-18  9:39                                               ` Parav Pandit
2020-08-19  3:30                                                 ` Yan Zhao
2020-08-19  5:58                                                   ` Parav Pandit
2020-08-19  9:41                                                     ` Jason Wang
2020-08-19  6:57                                                   ` [ovirt-devel] " Jason Wang
2020-08-19  6:59                                                     ` Yan Zhao
2020-08-19  7:39                                                       ` Jason Wang
2020-08-19  8:13                                                         ` Yan Zhao
2020-08-19  9:28                                                           ` Jason Wang
2020-08-20 12:27                                                             ` Cornelia Huck
2020-08-21  3:14                                                               ` Jason Wang
2020-08-21 14:52                                                                 ` Cornelia Huck
2020-08-31  3:07                                                                   ` Jason Wang
2020-08-19 17:50                                                   ` Alex Williamson
2020-08-20  0:18                                                     ` Yan Zhao
2020-08-20  3:13                                                       ` Alex Williamson
2020-08-20  3:09                                                         ` Yan Zhao
2020-08-19  2:54                                               ` Jason Wang
2020-08-20  0:39                                               ` Yan Zhao
2020-08-20  1:29                                                 ` Sean Mooney
2020-08-20  4:01                                                   ` Yan Zhao [this message]
2020-08-20  5:16                                                     ` Sean Mooney
2020-08-20  6:27                                                       ` Yan Zhao
2020-08-20 13:24                                                         ` Sean Mooney
2020-08-26  8:54                                                           ` Yan Zhao
2020-08-20  3:22                                                 ` Alex Williamson
2020-08-20  3:16                                                   ` Yan Zhao
2020-08-25 14:39                                                     ` Cornelia Huck
2020-08-26  6:41                                                       ` Yan Zhao
2020-08-28 13:47                                                         ` Cornelia Huck
2020-08-28 14:04                                                           ` Sean Mooney
2020-08-31  4:43                                                             ` Yan Zhao
2020-09-08 14:41                                                               ` Cornelia Huck
2020-09-09  2:13                                                                 ` Yan Zhao
2020-09-10 12:38                                                                   ` Cornelia Huck
2020-09-10 12:50                                                                     ` Sean Mooney
2020-09-10 18:02                                                                       ` Alex Williamson
2020-09-11  0:56                                                                         ` Yan Zhao
2020-09-11 10:08                                                                           ` Cornelia Huck
2020-09-11 10:18                                                                             ` Tian, Kevin
2020-09-11 16:51                                                                           ` Alex Williamson
2020-09-14 13:48                                                                             ` Zeng, Xin
2020-09-14 14:44                                                                               ` Alex Williamson
2020-09-09  5:37                                                               ` Yan Zhao
2020-08-31  2:23                                                           ` Yan Zhao
2020-08-19  2:38                                             ` Jason Wang
2020-08-18  9:32                                           ` Parav Pandit
2020-08-19  2:45                                             ` Jason Wang
2020-08-19  5:26                                               ` Parav Pandit
2020-08-19  6:48                                                 ` Jason Wang
2020-08-19  6:53                                                   ` Parav Pandit
2020-07-29 19:05             ` Dr. David Alan Gilbert

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