> -----Original Message----- > From: Kevin Wolf [mailto:kw...@redhat.com] > Sent: 02 November 2018 11:04 > To: Tim Smith <tim.sm...@citrix.com> > Cc: xen-de...@lists.xenproject.org; qemu-de...@nongnu.org; qemu- > bl...@nongnu.org; Anthony Perard <anthony.per...@citrix.com>; Paul Durrant > <paul.durr...@citrix.com>; Stefano Stabellini <sstabell...@kernel.org>; > Max Reitz <mre...@redhat.com>; arm...@redhat.com > Subject: xen_disk qdevification (was: [PATCH 0/3] Performance improvements > for xen_disk v2) > > Am 02.11.2018 um 11:00 hat Tim Smith geschrieben: > > A series of performance improvements for disks using the Xen PV ring. > > > > These have had fairly extensive testing. > > > > The batching and latency improvements together boost the throughput > > of small reads and writes by two to six percent (measured using fio > > in the guest) > > > > Avoiding repeated calls to posix_memalign() reduced the dirty heap > > from 25MB to 5MB in the case of a single datapath process while also > > improving performance. > > > > v2 removes some checkpatch complaints and fixes the CCs > > Completely unrelated, but since you're the first person touching > xen_disk in a while, you're my victim: > > At KVM Forum we discussed sending a patch to deprecate xen_disk because > after all those years, it still hasn't been converted to qdev. Markus is > currently fixing some other not yet qdevified block device, but after > that xen_disk will be the only one left. > > A while ago, a downstream patch review found out that there are some QMP > commands that would immediately crash if a xen_disk device were present > because of the lacking qdevification. This is not the code quality > standard I envision for QEMU. It's time for non-qdev devices to go. > > So if you guys are still interested in the device, could someone please > finally look into converting it? >
I have a patch series to do exactly this. It's somewhat involved as I need to convert the whole PV backend infrastructure. I will try to rebase and clean up my series a.s.a.p. Paul > Kevin