RE: [Xen-devel] Xenoprof: getting Oprofile out of timer mode?

["Santos, Jose Renato G" <joserenato.santos@xxxxxx>]

Andrei,

The xenoprof initialization routine is failing. The returned
error is ENODEV. There are only two conditions that would
cause this error: 1) the CPU does not have a local APIC,
2) the CPU model (vendor,family) is not recognized as a known model.
But if either one of this was really true you would see the
same error on vanila linux (without Xen).
I am not sure what could be causing this for you. Maybe Xen detection
of the local APIC is slightly different than in Linux causing
Xen to not detect it (???) (Humm, this seems unlikely, but I 
could not find any other explanation yet ...). Maybe, someone
more faniliar with APIC detection in Xen could comment if
APIC detection for Pentium III could diverge from what linux does...

If you apply the attached patch to "xen/arch/x86/oprofile/nmi_int.c"
Xenoprof will print some error message on the Xen console
when this error happens. Looking at this we will be able
to determine if the error is related to APIC or the cpu model.

I will be traveling later today and will not be accessing my
email until next Monday.
Unfortunately, I will only be able to continue this discussion
after I come back

Good luck,

Renato

>> -----Original Message-----
>> From: alifchits@xxxxxxxxx [mailto:alifchits@xxxxxxxxx] On 
>> Behalf Of Andrei Lifchits
>> Sent: Tuesday, April 18, 2006 12:52 PM
>> To: Santos, Jose Renato G
>> Cc: xen-devel@xxxxxxxxxxxxxxxxxxx; Gitika Aggarwal
>> Subject: Re: [Xen-devel] Xenoprof: getting Oprofile out of 
>> timer mode?
>> 
>> Hi Renato,
>> 
>> I'm using Xen unstable where you added builtin Xenoprof 
>> support (the image is called xen-3.0-unstable.gz, I 
>> downloaded the source on Apr 13). Oprofile is built into the kernel.
>> I'm attaching the kernel and Xen logs to this email.
>> 
>> Thanks,
>> Andrei
>> 
>> 
>> On 4/18/06, Santos, Jose Renato G <joserenato.santos@xxxxxx> wrote:
>> >
>> > Andrei,
>> >
>> > I am not sure what is causing XenOprofile to not start properly in 
>> > your instalations. Can you please, send me your kernel log 
>> (dmesg) and 
>> > Xen log (xm dmesg).
>> > That might give us some hint.
>> > What Xen version are you using?
>> > Are you using Oprofile as a kernel module or builtin?
>> >
>> > Thanks
>> >
>> > Renato
>> >
>> > >> -----Original Message-----
>> > >> From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
>> > >> [mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On 
>> Behalf Of Andrei 
>> > >> Lifchits
>> > >> Sent: Monday, April 17, 2006 6:37 PM
>> > >> To: xen-devel@xxxxxxxxxxxxxxxxxxx
>> > >> Cc: Gitika Aggarwal
>> > >> Subject: [Xen-devel] Xenoprof: getting Oprofile out of 
>> timer mode?
>> > >>
>> > >> Hello,
>> > >>
>> > >> I'm having a problem with Xenoprof: I'm trying to 
>> profile XenLinux
>> > >> (2.6.16) on a Pentium III desktop machine, by starting Oprofile 
>> > >> (opcontrol --start). However, when I specify a particular event 
>> > >> (with the --event option), Oprofile says it's in the 
>> Timer Mode and 
>> > >> cannot profile events. The Oprofile FAQ says the "lapic" option 
>> > >> must be passed to the kernel at boot time if that happens, but 
>> > >> doing so doesn't change anything for me. I should note that 
>> > >> Oprofile (without Xen support) works fine on this machine under 
>> > >> Fedora Core 4 (it doesn't go into Timer Mode), which 
>> implies that 
>> > >> the hardware support is present. Do you know what the 
>> problem might 
>> > >> be with XenLinux?
>> > >>
>> > >> Thank you,
>> > >> Andrei
>> > >>
>> > >> _______________________________________________
>> > >> Xen-devel mailing list
>> > >> Xen-devel@xxxxxxxxxxxxxxxxxxx
>> > >> http://lists.xensource.com/xen-devel
>> > >>
>> >
>> 

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