* Alexey Perevalov ([email protected]) wrote: > On 09/21/2017 03:33 PM, Dr. David Alan Gilbert wrote: > > * Alexey Perevalov ([email protected]) wrote: > > > Reviewed-by: Dr. David Alan Gilbert <[email protected]> > > > Signed-off-by: Alexey Perevalov <[email protected]> > > Although it does have my R-b it might be worth adding some clarification > > that it's a measure of when *all* cpus are blocked and so isn't a > > total measure of impact of postcopy (when blocking some of them). > yes, maybe additional clarification is necessary. > now we have both values: > {"return": {"postcopy-blocktime": 5691, "status": "completed", > "postcopy-vcpu-blocktime": [7671, 6388]}} > where postcopy-blocktime is for *all* and postcopy-vcpu-blocktime is per > vCPU, > it's really worth to describe it, like: > > Blocktime is a postcopy live migration metric, intended to show > how long the vCPU was in state of interruptible 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.
Yep that seems OK. Dave > -- > Best regards, > Alexey Perevalov > > > > > Dave > > > > > --- > > > docs/devel/migration.txt | 10 ++++++++++ > > > 1 file changed, 10 insertions(+) > > > > > > diff --git a/docs/devel/migration.txt b/docs/devel/migration.txt > > > index 1b940a8..4b625ca 100644 > > > --- a/docs/devel/migration.txt > > > +++ b/docs/devel/migration.txt > > > @@ -402,6 +402,16 @@ 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. > > > +This value is 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. > > > + > > > Note: During the postcopy phase, the bandwidth limits set using > > > migrate_set_speed is ignored (to avoid delaying requested pages that > > > the destination is waiting for). > > > -- > > > 1.9.1 > > > > > -- > > Dr. David Alan Gilbert / [email protected] / Manchester, UK > > > > > > > > -- Dr. David Alan Gilbert / [email protected] / Manchester, UK
