This is the deivce part implementation to add a new feature,
VIRTIO_BALLOON_F_FREE_PAGE_HINT to the virtio-balloon device. The device
receives the guest free page hints from the driver and clears the
corresponding bits in the dirty bitmap, so that those free pages are
not sent by the migration thread to the destination.
*Tests
1 Test Environment
Host: Intel(R) Xeon(R) CPU E5-2699 v4 @ 2.20GHz
Migration setup: migrate_set_speed 100G, migrate_set_downtime 400ms
2 Test Results (results are averaged over several repeated runs)
2.1 Guest setup: 8G RAM, 4 vCPU
2.1.1 Idle guest live migration time
Optimization v.s. Legacy = 620ms vs 2970ms
--> ~79% reduction
2.1.2 Guest live migration with Linux compilation workload
(i.e. make bzImage -j4) running
1) Live Migration Time:
Optimization v.s. Legacy = 2273ms v.s. 4502ms
--> ~50% reduction
2) Linux Compilation Time:
Optimization v.s. Legacy = 8min42s v.s. 8min43s
--> no obvious difference
2.2 Guest setup: 128G RAM, 4 vCPU
2.2.1 Idle guest live migration time
Optimization v.s. Legacy = 5294ms vs 41651ms
--> ~87% reduction
2.2.2 Guest live migration with Linux compilation workload
1) Live Migration Time:
Optimization v.s. Legacy = 8816ms v.s. 54201ms
--> 84% reduction
2) Linux Compilation Time:
Optimization v.s. Legacy = 8min30s v.s. 8min36s
--> no obvious difference
ChangeLog:
v8->v9:
bitmap:
- fix bitmap_count_one to handle the nbits=0 case
migration:
- replace the ram save notifier chain with a more general precopy
notifier chain, which is similar to the postcopy notifier chain.
- Avoid exposing the RAMState struct, and add a function,
precopy_disable_bulk_stage, to let the virtio-balloon notifier
callback to disable the bulk stage flag.
virtio-balloon:
- Remove VIRTIO_BALLOON_F_PAGE_POISON from this series as it is not
a limit to the free page optimization now. Plan to add the device
support for VIRTIO_BALLOON_F_PAGE_POISON in another patch later.
Previous changelog:
https://lists.gnu.org/archive/html/qemu-devel/2018-06/msg01908.html
Wei Wang (8):
bitmap: fix bitmap_count_one
bitmap: bitmap_count_one_with_offset
migration: use bitmap_mutex in migration_bitmap_clear_dirty
migration: API to clear bits of guest free pages from the dirty bitmap
migration/ram.c: add a notifier chain for precopy
migration/ram.c: add a function to disable the bulk stage
migration: move migrate_postcopy() to include/migration/misc.h
virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT
hw/virtio/virtio-balloon.c | 255 ++++++++++++++++++++++++
include/hw/virtio/virtio-balloon.h | 28 ++-
include/migration/misc.h | 16 ++
include/qemu/bitmap.h | 17 ++
include/standard-headers/linux/virtio_balloon.h | 5 +
migration/migration.h | 2 -
migration/ram.c | 91 +++++++++
vl.c | 1 +
8 files changed, 412 insertions(+), 3 deletions(-)
--
1.8.3.1
