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authorHyman Huang(黄勇) <yong.huang@smartx.com>2023-06-07 23:30:50 +0800
committerJuan Quintela <quintela@redhat.com>2023-07-26 10:55:56 +0200
commitdc62395557b29312a9c2f9a1e0beece2557c3078 (patch)
tree46c5d5bb78b2371af4825676d451b74af3abeb6e /qapi
parent09f9ec99133ab5735b57486323d9c592630c9fc1 (diff)
migration: Introduce dirty-limit capability
Introduce migration dirty-limit capability, which can be turned on before live migration and limit dirty page rate durty live migration. Introduce migrate_dirty_limit function to help check if dirty-limit capability enabled during live migration. Meanwhile, refactor vcpu_dirty_rate_stat_collect so that period can be configured instead of hardcoded. dirty-limit capability is kind of like auto-converge but using dirty limit instead of traditional cpu-throttle to throttle guest down. To enable this feature, turn on the dirty-limit capability before live migration using migrate-set-capabilities, and set the parameters "x-vcpu-dirty-limit-period", "vcpu-dirty-limit" suitably to speed up convergence. Signed-off-by: Hyman Huang(黄勇) <yong.huang@smartx.com> Acked-by: Peter Xu <peterx@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Message-Id: <168618975839.6361.17407633874747688653-4@git.sr.ht> Signed-off-by: Juan Quintela <quintela@redhat.com>
Diffstat (limited to 'qapi')
-rw-r--r--qapi/migration.json13
1 files changed, 12 insertions, 1 deletions
diff --git a/qapi/migration.json b/qapi/migration.json
index 22104cef08..e094438d74 100644
--- a/qapi/migration.json
+++ b/qapi/migration.json
@@ -497,6 +497,16 @@
# are present. 'return-path' capability must be enabled to use
# it. (since 8.1)
#
+# @dirty-limit: If enabled, migration will use the dirty-limit algo to
+# throttle down guest instead of auto-converge algo.
+# Throttle algo only works when vCPU's dirtyrate greater
+# than 'vcpu-dirty-limit', read processes in guest os
+# aren't penalized any more, so this algo can improve
+# performance of vCPU during live migration. This is an
+# optional performance feature and should not affect the
+# correctness of the existing auto-converge algo.
+# (since 8.1)
+#
# Features:
#
# @unstable: Members @x-colo and @x-ignore-shared are experimental.
@@ -512,7 +522,8 @@
'dirty-bitmaps', 'postcopy-blocktime', 'late-block-activate',
{ 'name': 'x-ignore-shared', 'features': [ 'unstable' ] },
'validate-uuid', 'background-snapshot',
- 'zero-copy-send', 'postcopy-preempt', 'switchover-ack'] }
+ 'zero-copy-send', 'postcopy-preempt', 'switchover-ack',
+ 'dirty-limit'] }
##
# @MigrationCapabilityStatus: