> -----Original Message-----
> From: xen-users-bounces@xxxxxxxxxxxxxxxxxxx
> [mailto:xen-users-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of anant
> Sent: 31 January 2007 11:11
> To: xen-users@xxxxxxxxxxxxxxxxxxx
> Subject: [Xen-users] RE: RE: RE: RE: RE: can XEN be extended ?
>
>
> OK then how can i be sure that the HW value that i am getting is real.
> Actually at present i cant see many instances created of the
> classes in
> openWBEM. So i cant really compoare it with the BIOS. I got the memory
> instance so i compared that.
> I guess may be the provider that is installed in my system
> doesnt provide
> much info. If i install some other provider, do you think
> that could solve
> my problem to compare things And if yes then which provider
> should i go for.
> I hope i am not asking to much of openWBEM question out here.
> Well its just
> that you know much about it.
> So let me know if you are not sure about it.
Well, the real hardware measurements that you mentioned before,
fan-speed and CPU temp for example, are either not going to be available
(because you don't have the right "provider" or drivers necesary), or
they are going to be the real hardware values. Memory is different
because Xen handles the memory on behalf of the domains, whilst Xen
doesn't care what the CPU temperature is, or how fast the fan is
spinning - it has NO BUSINESS dealing with it, and therefore it doesn't.
[Note that the memory values you do read out will of course be accurate
for WHAT Dom0 THINKS the memory is - just that it's not going to show
the REAL HARDWARE VALUES!]
You may want to check which modules are compiled in for the Hardware
Monitoring - in my unstable setup, only an SMSC LPC47B397-NC is
included, but there's a list of quite a few more (grep "CONFIG_SENSORS"
says that there are 47 items matching that in .config). So what I'm
saying is that if your monitoring hardware isn't supported by your
kernel build, you're not going to get any data.
The first primary setting would be CONFIG_HWMON=y in your config
file.... Then you need CONFIG_SENSORS_xxx to be set, where xxx is the
name of your hardware monitoring device.
There may of course be reasons why the hardware monitoring drivers
wouldn't work correctly (or crash the system) when used in conjuntion
with Xen, but that should be fairly obvious (such as completely bogus
results, -1, 0 or other unrealistic numbers most likely), and it's
actually unlikely that this is the case - because these drivers don't do
anything particularly complicated, and they should be just
reading/writing IO ports (I looked at two different drivers, and both
are pretty trivial IO port work, so should work just fine in Xen - but
there are of course another 45 of them to look at to make complete set -
but I doubt the others are dramatically different, as it's not
high-speed interfaces, and keeping the interface simple helps the
hardware designer as well as the software designer!)
Note: I know roughly how this is SUPPOSED to work, but I haven't used
the HWMON stuff for a long time, and when I did, it was just to figure
out that it worked for someone else to use, and I have no idea
whatsoever how openWBEM actually gatheres the information on these
things...
--
Mats
>
> thanks
>
>
>
> Petersson, Mats wrote:
> >
> >> -----Original Message-----
> >> From: xen-users-bounces@xxxxxxxxxxxxxxxxxxx
> >> [mailto:xen-users-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of anant
> >> Sent: 30 January 2007 10:55
> >> To: xen-users@xxxxxxxxxxxxxxxxxxx
> >> Subject: [Xen-users] RE: RE: RE: RE: can XEN be extended ?
> >>
> >>
> >>
> >>
> >> >Where are you running openWBEM? In Dom0 it should give you
> >> real hardware
> >> >information.
> >>
> >> Yeah openWBEM is runnning in dom0
> >>
> >> >In Dom0 it should give you real hardware
> >> >information.
> >>
> >> I am bit confused here. I was looking for a proof whether it
> >> gives real
> >> value or no...
> >>
> >> Well i was monitoring the memory value......i.e.
> >>
> >> Actual Memory = 1024000 KB RAM approx.
> >>
> >> after entering command cat /proc/meminfo over terminal.. i got
> >>
> >> Total Memory = 953344 KB [loss of 70656KB memory, that
> means this much
> >> amount of memory is consumed by running OS]
> >
> > 70 MB used by the OS seems about right.
> >
> >> Free Memory = 560828 KB
> >>
> >> Now started openWBEM
> >>
> >> here Total memory = 560828 KB
> >> Free memory = 444608 KB [loss of 116220 KB memory,
> >> that means this
> >> much amount of memory took my openWBEM to get running]
> >
> > Not necessarily - see below.
> >
> >>
> >> Now closed openWBEM and started Virtual OS on top of XEN
> >> Memory allocated to Virtual OS = 400MB
> >>
> >> now again checking memory
> >>
> >> Terminal ->
> >> Total Memory = 606208 KB
> >> Free Memory = 15628 KB
> >>
> >> OpenWBEM ->
> >> Total Memory = 606208 KB
> >> Free Memory = 8256KB [This time there is loss of 7372KB
> >> memory, that means
> >> this time openWBEM tool this much memory to get running]
> >>
> >> Why is the difference in this free memory all the
> >> time....Does it makes any
> >> sence to you...?
> >> Do you think the value is of real hardware...or no....?
> >
> > "Memory" is not something that you can "measure"
> realisticly from within
> > even Dom0, as it's hidden from even Dom0 how much memory
> there REALLY is
> > in the machine (using the dom0_mem=xxx will make Dom0
> believe that the
> > actual amount of memory is xxx). Only the hypervisor knows how much
> > memory there REALLY is in the system. "xm info" will tell you that.
> >
> > Next comes "free" memory. That's very much like measuring
> the length of
> > a rubber-band. It depends on what you're doing with the machine, how
> > much memory is free. And the fact that there is NO free
> memory doesn't
> > necessarily mean that you can't use more memory either -
> because there
> > is swap to store "not currently needed" data/code in.
> >
> > The OS will deal with free memory in various ways,
> including using it
> > for buffers for disk-caching and freeing memory in reserve for new
> > applications in case of "low memory" situations. Also, loading an
> > application will drag in shared libraries (.so files in
> Linux, .dll in
> > Windows). These may be kept resident in memory if there's
> no demand for
> > more memory (this is why starting large apps a second time is often
> > quicker than the first time - the shared libraries have
> been loaded, and
> > don't need to be loaded again). Of course, if you have just
> loaded 100MB
> > of shared libraries into memory, and there's no demand for
> memory at the
> > present time, it's going to show 100MB less than it did
> before. If you
> > then load something that requires a large amount of memory
> but not using
> > much of the shared libraries, some unused libraries may be
> unloaded and
> > when you quit the large-amount-of-memory app, the amount of
> free memory
> > is larger than it was before you started the app (because the shared
> > libraries that are still not needed are no longer in memory).
> >
> > And just to add complexity, the xend, xenstore and other
> xen components
> > may well use some amount of memory within Dom0 for each
> domain that you
> > create, so the amount of free memory is definitely expected
> to reduce
> > there, even if all other uses of memory stay constant.
> >
> > --
> > Mats
> >>
> >> Thanks
> >>
> >>
> >> --
> >> View this message in context:
> >> http://www.nabble.com/can-XEN-be-extended---tf3097151.html#a8707383
> >> Sent from the Xen - User mailing list archive at Nabble.com.
> >>
> >>
> >> _______________________________________________
> >> Xen-users mailing list
> >> Xen-users@xxxxxxxxxxxxxxxxxxx
> >> http://lists.xensource.com/xen-users
> >>
> >>
> >>
> >
> >
> >
> > _______________________________________________
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> > Xen-users@xxxxxxxxxxxxxxxxxxx
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> >
> >
>
> --
> View this message in context:
> http://www.nabble.com/can-XEN-be-extended---tf3097151.html#a8727077
> Sent from the Xen - User mailing list archive at Nabble.com.
>
>
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