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From: Alex Williamson <alex.williamson@redhat.com>
To: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Yan Zhao <yan.y.zhao@intel.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: Thu, 28 May 2020 16:59:06 -0600	[thread overview]
Message-ID: <20200528165906.7d03f689@x1.home> (raw)
In-Reply-To: <20200527084822.GC3001@work-vm>

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,

Alex


  parent reply	other threads:[~2020-05-28 22:59 UTC|newest]

Thread overview: 40+ 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 ` [PATCH Kernel v22 1/8] vfio: UAPI for migration interface for device state 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 ` [PATCH Kernel v22 3/8] vfio iommu: Cache pgsize_bitmap in struct vfio_iommu Kirti Wankhede
2020-05-20 10:08   ` Cornelia Huck
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 ` [PATCH Kernel v22 5/8] vfio iommu: Implementation of ioctl " Kirti Wankhede
2020-05-18 21:53   ` Alex Williamson
2020-05-19  7:11     ` 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
2020-05-19  6:54   ` Kirti Wankhede
2020-05-20 10:27     ` Cornelia Huck
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
2020-05-20 10:42   ` Cornelia Huck
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
2020-05-19  6:54   ` Kirti Wankhede
2020-05-19 16:58 ` [PATCH Kernel v22 0/8] Add UAPIs to support migration for VFIO devices Alex Williamson
2020-05-20  2:55   ` Yan Zhao
2020-05-20 13:40     ` Kirti Wankhede
2020-05-20 16:46       ` Alex Williamson
2020-05-21  5:08         ` Yan Zhao
2020-05-21  7:09           ` Kirti Wankhede
2020-05-21  7:04             ` Yan Zhao
2020-05-21  7:28               ` Kirti Wankhede
2020-05-21  7:32               ` Kirti Wankhede
2020-05-25  6:59   ` Yan Zhao
2020-05-25 13:20     ` Kirti Wankhede
2020-05-26 20:19       ` Alex Williamson
2020-05-27  6:23         ` Yan Zhao
2020-05-27  8:48           ` Dr. David Alan Gilbert
2020-05-28  8:01             ` Yan Zhao
2020-05-28 22:53               ` Alex Williamson
2020-05-29 11:12                 ` Dr. David Alan Gilbert
2020-05-28 22:59             ` Alex Williamson [this message]
2020-05-29  4:15               ` Yan Zhao
2020-05-29 17:57               ` Kirti Wankhede

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