Please, do not post to several libvirt lists at once.

I am writing a code using libvirt API to migrate VM between two physical hosts *(QEMU/KVM) , *say some *n *number of times.

*1)* I am using right now* virDomainPtr virDomainMigrate (.......) *and to calculate the total migration time I am using something like this:

*clock_gettime(CLOCK_MONOTONIC_RAW,&begin); * *migrate*(domainToMigrate,nodeToMigrate);

*clock_gettime(CLOCK_MONOTONIC_RAW,&end);*

*Total Migration Time = end.tv_sec-begin.tv_sec*

Is this correct way to calculate total migration time. And is there some way to calculate the downtime (not how to set it)?

Well, just call virDomainGetJobStats and you will get both total time and downtime and many more.

virDomainGetJobStats <http://libvirt.org/html/libvirt-libvirt-domain.html#virDomainGetJobStats>

Yes, this is the right API to get all the statistics you want. It returns a list of (key, type, value) entires in params. The keys are VIR_DOMAIN_JOB_* (see http://libvirt.org/html/libvirt-libvirt-domain.html#VIR_DOMAIN_JOB_AUTO_CONV... and a lot of other VIR_DOMAIN_JOB_* macros following this one for details). You can look at http://libvirt.org/git/?p=libvirt.git;a=blob;f=tools/virsh-domain.c;h=93587e... In short, just call virTypedParamsGetULLong(params, nparams, VIR_DOMAIN_JOB_DOWNTIME, &value) to fetch downtime from params into value if it was present there (check return value of the API). The exact API to call is different for each type, although all migration statistics are unsigned long long so this one is all you need. BTW, you can call virDomainGetJobStats anytime while migration is running to monitor its progress. To check statistics of a completed migration it's easier to just register a callback for VIR_DOMAIN_EVENT_ID_JOB_COMPLETED event. See http://libvirt.org/git/?p=libvirt.git;a=blob;f=examples/object-events/event-... for an example. Jirka

On Tue, Jan 10, 2017 at 08:07:13PM +0530, Anubhav Guleria wrote:

Greetings,

I am writing a code using libvirt API to migrate VM between two physical hosts *(QEMU/KVM) , *say some *n *number of times.

*1)* I am using right now* virDomainPtr virDomainMigrate (.......) *and to calculate the total migration time I am using something like this:

*clock_gettime(CLOCK_MONOTONIC_RAW,&begin); * *migrate*(domainToMigrate,nodeToMigrate);

*clock_gettime(CLOCK_MONOTONIC_RAW,&end);*

*Total Migration Time = end.tv_sec-begin.tv_sec*

Is this correct way to calculate total migration time. And is there some way to calculate the downtime (not how to set it)?

Libvirt provides this information, I believe in virDomainGetJobStats(). If you call this function with flags |= VIR_DOMAIN_JOB_STATS_COMPLETED, it will return various information on a recently completed job (e.g. migration). You can also register a callback for VIR_DOMAIN_EVENT_ID_JOB_COMPLETED event, which will tell you all that right when the migration is completed.

*2) *I am interested in identifying in particular other statistics of migration like : *Number of iterations in Pre Copy*, *Memory transferred in each iteration* etc. I was going through the API and found* virDomainJobInfo <http://libvirt.org/html/libvirt-libvirt-domain.html#virDomainJobInfo> and virDomainGetJobStats <http://libvirt.org/html/libvirt-libvirt-domain.html#virDomainGetJobStats> *functions.But how to use them is not very clear. Can anyone point me to right place to achieve this objective?

int type = -1, nparams = 0; virTypedParameterPtr params = NULL; virDomainGetJobStats(domain, &type, ¶ms, &nparams, VIR_DOMAIN_JOB_STATS_COMPLETED) This should be enough ^^. Since migration should be a job on bothe source and destination, it may return different data, I'm not too sure about that. You'll have to try that out or hope that someone else will answer as well, sorry.

Thanks in advance. And sorry if that was too silly to ask.

Anubhav

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