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From: Yan Zhao <yan.y.zhao@intel.com>
To: Alex Williamson <alex.williamson@redhat.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>,
	Kirti Wankhede <kwankhede@nvidia.com>,
	cjia@nvidia.com, kevin.tian@intel.com, ziye.yang@intel.com,
	changpeng.liu@intel.com, yi.l.liu@intel.com, mlevitsk@redhat.com,
	eskultet@redhat.com, cohuck@redhat.com,
	jonathan.davies@nutanix.com, eauger@redhat.com, aik@ozlabs.ru,
	pasic@linux.ibm.com, felipe@nutanix.com,
	Zhengxiao.zx@alibaba-inc.com, shuangtai.tst@alibaba-inc.com,
	Ken.Xue@amd.com, zhi.a.wang@intel.com, qemu-devel@nongnu.org,
	kvm@vger.kernel.org
Subject: Re: [PATCH Kernel v22 0/8] Add UAPIs to support migration for VFIO devices
Date: Fri, 29 May 2020 00:15:17 -0400	[thread overview]
Message-ID: <20200529041516.GE1378@joy-OptiPlex-7040> (raw)
In-Reply-To: <20200528165906.7d03f689@x1.home>

On Thu, May 28, 2020 at 04:59:06PM -0600, Alex Williamson wrote:
> On Wed, 27 May 2020 09:48:22 +0100
> "Dr. David Alan Gilbert" <dgilbert@redhat.com> wrote:
> > * Yan Zhao (yan.y.zhao@intel.com) wrote:
> > > BTW, for viommu, the downtime data is as below. under the same network
> > > condition and guest memory size, and no running dirty data/memory produced
> > > by device.
> > > (1) viommu off
> > > single-round dirty query: downtime ~100ms   
> > 
> > Fine.
> > 
> > > (2) viommu on
> > > single-round dirty query: downtime 58s   
> > 
> > Youch.
> 
> Double Youch!  But we believe this is because we're getting the dirty
> bitmap one IOMMU leaf page at a time, right?  We've enable the kernel
> to get a dirty bitmap across multiple mappings, but QEMU isn't yet
> taking advantage of it.  Do I have this correct?  Thanks,
>
Yes, I think so, but I haven't looked into it yet.

Thanks
Yan

WARNING: multiple messages have this Message-ID (diff)
From: Yan Zhao <yan.y.zhao@intel.com>
To: Alex Williamson <alex.williamson@redhat.com>
Cc: Zhengxiao.zx@alibaba-inc.com, kevin.tian@intel.com,
	yi.l.liu@intel.com, cjia@nvidia.com, kvm@vger.kernel.org,
	eskultet@redhat.com, ziye.yang@intel.com, qemu-devel@nongnu.org,
	cohuck@redhat.com, shuangtai.tst@alibaba-inc.com,
	"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
	zhi.a.wang@intel.com, mlevitsk@redhat.com, pasic@linux.ibm.com,
	aik@ozlabs.ru, Kirti Wankhede <kwankhede@nvidia.com>,
	eauger@redhat.com, felipe@nutanix.com,
	jonathan.davies@nutanix.com, changpeng.liu@intel.com,
	Ken.Xue@amd.com
Subject: Re: [PATCH Kernel v22 0/8] Add UAPIs to support migration for VFIO devices
Date: Fri, 29 May 2020 00:15:17 -0400	[thread overview]
Message-ID: <20200529041516.GE1378@joy-OptiPlex-7040> (raw)
In-Reply-To: <20200528165906.7d03f689@x1.home>

On Thu, May 28, 2020 at 04:59:06PM -0600, Alex Williamson wrote:
> On Wed, 27 May 2020 09:48:22 +0100
> "Dr. David Alan Gilbert" <dgilbert@redhat.com> wrote:
> > * Yan Zhao (yan.y.zhao@intel.com) wrote:
> > > BTW, for viommu, the downtime data is as below. under the same network
> > > condition and guest memory size, and no running dirty data/memory produced
> > > by device.
> > > (1) viommu off
> > > single-round dirty query: downtime ~100ms   
> > 
> > Fine.
> > 
> > > (2) viommu on
> > > single-round dirty query: downtime 58s   
> > 
> > Youch.
> 
> Double Youch!  But we believe this is because we're getting the dirty
> bitmap one IOMMU leaf page at a time, right?  We've enable the kernel
> to get a dirty bitmap across multiple mappings, but QEMU isn't yet
> taking advantage of it.  Do I have this correct?  Thanks,
>
Yes, I think so, but I haven't looked into it yet.

Thanks
Yan


  reply	other threads:[~2020-05-29  4:25 UTC|newest]

Thread overview: 80+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-18  5:56 [PATCH Kernel v22 0/8] Add UAPIs to support migration for VFIO devices Kirti Wankhede
2020-05-18  5:56 ` Kirti Wankhede
2020-05-18  5:56 ` [PATCH Kernel v22 1/8] vfio: UAPI for migration interface for device state Kirti Wankhede
2020-05-18  5:56   ` Kirti Wankhede
2020-05-18  5:56 ` [PATCH Kernel v22 2/8] vfio iommu: Remove atomicity of ref_count of pinned pages Kirti Wankhede
2020-05-18  5:56   ` Kirti Wankhede
2020-05-18  5:56 ` [PATCH Kernel v22 3/8] vfio iommu: Cache pgsize_bitmap in struct vfio_iommu Kirti Wankhede
2020-05-18  5:56   ` Kirti Wankhede
2020-05-20 10:08   ` Cornelia Huck
2020-05-20 10:08     ` Cornelia Huck
2020-05-20 14:46     ` Kirti Wankhede
2020-05-20 14:46       ` Kirti Wankhede
2020-05-18  5:56 ` [PATCH Kernel v22 4/8] vfio iommu: Add ioctl definition for dirty pages tracking Kirti Wankhede
2020-05-18  5:56   ` Kirti Wankhede
2020-05-18  5:56 ` [PATCH Kernel v22 5/8] vfio iommu: Implementation of ioctl " Kirti Wankhede
2020-05-18  5:56   ` Kirti Wankhede
2020-05-18 21:53   ` Alex Williamson
2020-05-18 21:53     ` Alex Williamson
2020-05-19  7:11     ` Kirti Wankhede
2020-05-19  7:11       ` Kirti Wankhede
2020-05-19  6:52       ` Kirti Wankhede
2020-05-19  6:52         ` Kirti Wankhede
2020-05-18  5:56 ` [PATCH Kernel v22 6/8] vfio iommu: Update UNMAP_DMA ioctl to get dirty bitmap before unmap Kirti Wankhede
2020-05-18  5:56   ` Kirti Wankhede
2020-05-19  6:54   ` Kirti Wankhede
2020-05-19  6:54     ` Kirti Wankhede
2020-05-20 10:27     ` Cornelia Huck
2020-05-20 10:27       ` Cornelia Huck
2020-05-20 15:16       ` Kirti Wankhede
2020-05-20 15:16         ` Kirti Wankhede
2020-05-18  5:56 ` [PATCH Kernel v22 7/8] vfio iommu: Add migration capability to report supported features Kirti Wankhede
2020-05-18  5:56   ` Kirti Wankhede
2020-05-20 10:42   ` Cornelia Huck
2020-05-20 10:42     ` Cornelia Huck
2020-05-20 15:23     ` Kirti Wankhede
2020-05-20 15:23       ` Kirti Wankhede
2020-05-18  5:56 ` [PATCH Kernel v22 8/8] vfio: Selective dirty page tracking if IOMMU backed device pins pages Kirti Wankhede
2020-05-18  5:56   ` Kirti Wankhede
2020-05-19  6:54   ` Kirti Wankhede
2020-05-19  6:54     ` Kirti Wankhede
2020-05-19 16:58 ` [PATCH Kernel v22 0/8] Add UAPIs to support migration for VFIO devices Alex Williamson
2020-05-19 16:58   ` Alex Williamson
2020-05-20  2:55   ` Yan Zhao
2020-05-20  2:55     ` Yan Zhao
2020-05-20 13:40     ` Kirti Wankhede
2020-05-20 13:40       ` Kirti Wankhede
2020-05-20 16:46       ` Alex Williamson
2020-05-20 16:46         ` Alex Williamson
2020-05-21  5:08         ` Yan Zhao
2020-05-21  5:08           ` Yan Zhao
2020-05-21  7:09           ` Kirti Wankhede
2020-05-21  7:09             ` Kirti Wankhede
2020-05-21  7:04             ` Yan Zhao
2020-05-21  7:04               ` Yan Zhao
2020-05-21  7:28               ` Kirti Wankhede
2020-05-21  7:28                 ` Kirti Wankhede
2020-05-21  7:32               ` Kirti Wankhede
2020-05-21  7:32                 ` Kirti Wankhede
2020-05-25  6:59   ` Yan Zhao
2020-05-25  6:59     ` Yan Zhao
2020-05-25 13:20     ` Kirti Wankhede
2020-05-25 13:20       ` Kirti Wankhede
2020-05-26 20:19       ` Alex Williamson
2020-05-26 20:19         ` Alex Williamson
2020-05-27  6:23         ` Yan Zhao
2020-05-27  6:23           ` Yan Zhao
2020-05-27  8:48           ` Dr. David Alan Gilbert
2020-05-27  8:48             ` Dr. David Alan Gilbert
2020-05-28  8:01             ` Yan Zhao
2020-05-28  8:01               ` Yan Zhao
2020-05-28 22:53               ` Alex Williamson
2020-05-28 22:53                 ` Alex Williamson
2020-05-29 11:12                 ` Dr. David Alan Gilbert
2020-05-29 11:12                   ` Dr. David Alan Gilbert
2020-05-28 22:59             ` Alex Williamson
2020-05-28 22:59               ` Alex Williamson
2020-05-29  4:15               ` Yan Zhao [this message]
2020-05-29  4:15                 ` Yan Zhao
2020-05-29 17:57               ` Kirti Wankhede
2020-05-29 17:57                 ` Kirti Wankhede

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