From: Alexey Perevalov Date: Mon, 30 Oct 2017 13:16:28 +0000 (+0300) Subject: migration: postcopy_blocktime documentation X-Git-Tag: v2.12.0-rc0~157^2~17 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=2f7dae9dd3b5bb436f6089816cf24f4d0867d32e;p=users%2Fdwmw2%2Fqemu.git migration: postcopy_blocktime documentation Reviewed-by: Dr. David Alan Gilbert Signed-off-by: Alexey Perevalov Reviewed-by: Juan Quintela Signed-off-by: Juan Quintela --- diff --git a/docs/devel/migration.rst b/docs/devel/migration.rst index bf97080dac..015a9ebdf7 100644 --- a/docs/devel/migration.rst +++ b/docs/devel/migration.rst @@ -401,6 +401,20 @@ will now cause the transition from precopy to postcopy. It can be issued immediately after migration is started or any time later on. Issuing it after the end of a migration is harmless. +Blocktime is a postcopy live migration metric, intended to show how +long the vCPU was in state of interruptable sleep due to pagefault. +That metric is calculated both for all vCPUs as overlapped value, and +separately for each vCPU. These values are calculated on destination +side. To enable postcopy blocktime calculation, enter following +command on destination monitor: + +``migrate_set_capability postcopy-blocktime on`` + +Postcopy blocktime can be retrieved by query-migrate qmp command. +postcopy-blocktime value of qmp command will show overlapped blocking +time for all vCPU, postcopy-vcpu-blocktime will show list of blocking +time per vCPU. + .. note:: During the postcopy phase, the bandwidth limits set using ``migrate_set_speed`` is ignored (to avoid delaying requested pages that