Date: Tue, 28 Aug 2018 06:37:10 -0700 (PDT) From: "Rodney W. Grimes" <freebsd-rwg@pdx.rh.CN85.dnsmgr.net> To: Anish <akgupt3@gmail.com> Cc: Fabian Freyer <fabian.freyer@physik.tu-berlin.de>, "freebsd-virtualization@freebsd.org" <freebsd-virtualization@freebsd.org> Subject: Re: on bhyve statistics Message-ID: <201808281337.w7SDbAEe015573@pdx.rh.CN85.dnsmgr.net> In-Reply-To: <CALnRwMSNMijJtj7Tt9497Pyh66JTe5cR=kjpiSZMd%2Bm8nx1D%2BQ@mail.gmail.com>
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> >> 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.
> -Anish
>
> On Mon, Aug 27, 2018 at 8:20 AM Rodney W. Grimes <
> freebsd-rwg@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,@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@freebsd.org
--
Rod Grimes rgrimes@freebsd.org
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