on bhyve statistics

[Marcelo Araujo]

On Tue, Aug 28, 2018, 9:38 PM Rodney W. Grimes <
freebsd-rwg at pdx.rh.cn85.dnsmgr.net> wrote:

> > >> Currently, bhyve does not expose any of these statistics. All the
> stats
> > > available through bhyvectl --get-stats seem to be coming from the VMM,
> > > not from the userspace emulation.
> >
> > >That is correct, byhvectl is a diagnostics tool for getting
> > information from the kernel/vmm module.
> >
> > bhyvectl provide stats related to processor vmx/svm from vmm.ko and is
> the
> > first thing you want to run for performance regression. It will be nice
> to
> > include it as part of bhyve perf tool/dashboard that you are intended to
> > build.
>
> From conversations with Peter Grehan he expressed that bhyvectl is
> purely a diagnostics tool that should not be depended on by any
> other tools.
>
> If you want to do similiar things you should program to the libvmmapi
> interface, not bhyvectl.
>

The libvmmapi is more an internal library for usage with bhyvectl and
bhyveload than for other purposes, of course it won't stop anybody to
extend it to achieve other goals.



> > -Anish
> >
> > On Mon, Aug 27, 2018 at 8:20 AM Rodney W. Grimes <
> > freebsd-rwg at pdx.rh.cn85.dnsmgr.net> wrote:
> >
> > > > Hi list,
> > > >
> > > > I'm currently looking at getting the libvirt prometheus exporter[1]
> to
> > > > work with libvirt+bhyve. In its current state this doesn't work
> because
> > > > at least one of the API calls exposed by libvirt isn't implemented by
> > > > the libvirt bhyve driver - so I started looking at implementing it.
> > > >
> > > > The first API call in question is virDomainBlockStats[2], which
> returns
> > > > statistics (number of read and written bytes and ops, respectively).
> > > >
> > > > Currently, bhyve does not expose any of these statistics. All the
> stats
> > > > available through bhyvectl --get-stats seem to be coming from the
> VMM,
> > > > not from the userspace emulation.
> > >
> > > That is correct, byhvectl is a diagnostics tool for getting
> > > information from the kernel/vmm module.
> > >
> > > > OTOH, I did see that there are *some*
> > > > stats being collected in bhyverun.c (see struct bhyvestats {...}
> > > > stats;). I can't see how these are exposed though -  a grep of
> /usr/src
> > > > turned up no other uses. Which brings me to the following questions:
> > > >
> > > > - are the stats in struct bhyvestats {...} stats exposed or used in
> any
> > > >   non-obvious way?
> > >
> > > Not that I am aware of.
> > >
> > > > - architecturally, what would be the best ways to get stats out of
> the
> > > >   user-space emulations? Off of the top of my head, I could think of
> the
> > > >   following possibilities:
> > > >   - prometheus exporter
> > > >   - having some socket or pipe to request them
> > > >   - DTrace probes
> > > >
> > > > I wouldn't mind implementing any of the above, and so would like to
> know
> > > > which of these (or other options) would be the most acceptable, and
> > > > would appreciate some guidance.
> > >
> > > I differ to others on what may be the best way to do this.
> > >
> > > > CC'ing novel@ for the libvirt side, and grehan@ for the
> architectural
> > > > bhyve questions.
> > >
> > > You should replace @grehan with @jhb, at tychon as Peter has moved on,
> > > and John and Tycho are now the bhyve maintainers.  I was going to
> > > add them, and remove Peter, but I see no cc: anyway, so I am sure
> > > that they are on the virtualization list though.
> > >
> > > > Fabian
> > > >
> > > > [1] https://github.com/kumina/libvirt_exporter
> > > > [2]
> > >
> https://libvirt.org/html/libvirt-libvirt-domain.html#virDomainBlockStats
> > > --
> > > Rod Grimes
> > > rgrimes at freebsd.org
>
> --
> Rod Grimes
> rgrimes at freebsd.org
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