* Cristian Klein (cristian.kl...@cs.umu.se) wrote: > On 04 Oct 2014, at 4:21 , Dr. David Alan Gilbert <dgilb...@redhat.com> wrote: > > > > > I've updated our github at: > > https://github.com/orbitfp7/qemu/tree/wp3-postcopy > > > > to have this version. > > > > and it corresponds to the tag: > > https://github.com/orbitfp7/qemu/releases/tag/wp3-postcopy-v4 > > Hi Dave, > > I just tested this version of post-copy using the libvirt patches I recently > posted and it works a lot better. The video streaming VM migrates with a > downtime of less than 1 second. Before post-copy finishes, the VM is a bit > slow but otherwise running well. > > I also tested the patches with a VM doing ?ping? and the downtime was around > 0.6 seconds. I suspect that this delay could be caused by libvirt and not by > qemu. Notice that, libvirt is a bit special, in the sense that the VM is > migrated in suspended state and resumed only after the network was set up on > the destination. I will investigate and let you know.
That's great news - although I'm not quite sure what caused the improvement, there were quite a few minor bug fixes and things but nothing that I can think of that would directly contribute (except the patches I'd sent you which you'd already tried). Dave > > Cristian > > > * Dr. David Alan Gilbert (git) (dgilb...@redhat.com) wrote: > >> From: "Dr. David Alan Gilbert" <dgilb...@redhat.com> > >> > >> Hi, > >> This is the 4th cut of my version of postcopy; it is designed for use with > >> the Linux kernel additions just posted by Andrea Arcangeli here: > >> > >> http://marc.info/?l=linux-kernel&m=141235633015100&w=2 > >> > >> (Note: This is a new version compared to my previous postcopy patchset; > >> you'll > >> need to update the kernel to the new version.) > >> > >> Other than the new kernel ABI (which is only a small change to the > >> userspace side); > >> the major changes are; > >> > >> a) Code for host page size != target page size > >> b) Support for migration over fd > >> From Cristian Klein; this is for libvirt support which Cristian > >> recently > >> posted to the libvirt list. > >> c) It's now build bisectable and builds on 32bit > >> > >> Testing wise; I've now done many thousand of postcopy migrations without > >> failure (both of idle and busy guests); so it seems pretty solid. > >> > >> Must-TODO's: > >> 1) A partially repeatable migration_cancel failure > >> 2) virt_test's migrate.with_reboot test is failing > >> 3) The ACPI fix in 2.1 that allowed migrating RAMBlocks to be larger than > >> the source feels like it needs looking at for postcopy. > >> 4) Paolo's comments with respect to the wakeup_request/is_running code > >> in the migration thread > >> 5) xbzrle needs disabling once in postcopy > >> > >> Later-TODO's: > >> 1) Control the rate of background page transfers during postcopy to > >> reduce their impact on the latency of postcopy requests. > >> 2) Work with RDMA > >> 3) Could destination RP be made blocking (as per discussion with Paolo; > >> I'm still worried that that changes too many assumptions) > >> > >> > >> > >> V4: > >> Initial support for host page size != target page size > >> - tested heavily on hps==tps > >> - only partially tested on hps!=tps systems > >> - This involved quite a bit of rework around the discard code > >> Updated to new kernel userfault ABI > >> - It won't work with the previous version > >> Fix mis-optimisation of postcopy request for wrong RAMBlock > >> request for block A offset n > >> un-needed fault for block B/m (already received - no req sent) > >> request for block B/l - wrongly sent as request for A/l > >> Fix thinko in discard bitmap processing (missed last word of bitmap) > >> Symptom: remap failures near the top of RAM if postcopy started late > >> Fix bug that caused kernel page acknowledgments to be misaligned > >> May have meant the guest was paused for longer than required > >> Fix potential for crashing cleaning up failed RP > >> Fixes in docs (from Yang) > >> Handle migration by fd as sockets if they are sockets > >> Build tested on 32bit > >> Fully build bisectable (x86-64) > >> > >> > >> Dave > >> > >> Cristian Klein (1): > >> Handle bi-directional communication for fd migration > >> > >> Dr. David Alan Gilbert (46): > >> QEMUSizedBuffer based QEMUFile > >> Tests: QEMUSizedBuffer/QEMUBuffer > >> Start documenting how postcopy works. > >> qemu_ram_foreach_block: pass up error value, and down the ramblock > >> name > >> improve DPRINTF macros, add to savevm > >> Add qemu_get_counted_string to read a string prefixed by a count byte > >> Create MigrationIncomingState > >> socket shutdown > >> Provide runtime Target page information > >> Return path: Open a return path on QEMUFile for sockets > >> Return path: socket_writev_buffer: Block even on non-blocking fd's > >> Migration commands > >> Return path: Control commands > >> Return path: Send responses from destination to source > >> Return path: Source handling of return path > >> qemu_loadvm errors and debug > >> ram_debug_dump_bitmap: Dump a migration bitmap as text > >> Rework loadvm path for subloops > >> Add migration-capability boolean for postcopy-ram. > >> Add wrappers and handlers for sending/receiving the postcopy-ram > >> migration messages. > >> QEMU_VM_CMD_PACKAGED: Send a packaged chunk of migration stream > >> migrate_init: Call from savevm > >> Allow savevm handlers to state whether they could go into postcopy > >> postcopy: OS support test > >> migrate_start_postcopy: Command to trigger transition to postcopy > >> MIG_STATE_POSTCOPY_ACTIVE: Add new migration state > >> qemu_savevm_state_complete: Postcopy changes > >> Postcopy page-map-incoming (PMI) structure > >> Postcopy: Maintain sentmap and calculate discard > >> postcopy: Incoming initialisation > >> postcopy: ram_enable_notify to switch on userfault > >> Postcopy: Postcopy startup in migration thread > >> Postcopy: Create a fault handler thread before marking the ram as > >> userfault > >> Page request: Add MIG_RPCOMM_REQPAGES reverse command > >> Page request: Process incoming page request > >> Page request: Consume pages off the post-copy queue > >> Add assertion to check migration_dirty_pages > >> postcopy_ram.c: place_page and helpers > >> Postcopy: Use helpers to map pages during migration > >> qemu_ram_block_from_host > >> Don't sync dirty bitmaps in postcopy > >> Host page!=target page: Cleanup bitmaps > >> Postcopy; Handle userfault requests > >> Start up a postcopy/listener thread ready for incoming page data > >> postcopy: Wire up loadvm_postcopy_ram_handle_{run,end} commands > >> End of migration for postcopy > >> > >> Makefile.objs | 2 +- > >> arch_init.c | 739 +++++++++++++++++++++++++-- > >> docs/migration.txt | 189 +++++++ > >> exec.c | 76 ++- > >> hmp-commands.hx | 15 + > >> hmp.c | 7 + > >> hmp.h | 1 + > >> include/exec/cpu-common.h | 8 +- > >> include/migration/migration.h | 130 +++++ > >> include/migration/postcopy-ram.h | 106 ++++ > >> include/migration/qemu-file.h | 47 ++ > >> include/migration/vmstate.h | 2 +- > >> include/qemu/sockets.h | 1 + > >> include/qemu/typedefs.h | 9 +- > >> include/sysemu/sysemu.h | 43 +- > >> migration-fd.c | 24 +- > >> migration-rdma.c | 4 +- > >> migration.c | 693 +++++++++++++++++++++++++- > >> postcopy-ram.c | 1016 > >> ++++++++++++++++++++++++++++++++++++++ > >> qapi-schema.json | 14 +- > >> qemu-file.c | 598 +++++++++++++++++++++- > >> qmp-commands.hx | 19 + > >> savevm.c | 881 +++++++++++++++++++++++++++++++-- > >> tests/Makefile | 2 +- > >> tests/test-vmstate.c | 74 +-- > >> util/qemu-sockets.c | 28 ++ > >> 26 files changed, 4550 insertions(+), 178 deletions(-) > >> create mode 100644 include/migration/postcopy-ram.h > >> create mode 100644 postcopy-ram.c > >> > >> -- > >> 1.9.3 > >> > >> > > -- > > Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK > -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
