[Xen-users] RE: xenoprof: operation 9 failed for dom0 (status: -1)

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

Try replacing "--active-domains=1" with "--passive-domains=1 passive-images=<domU-kernel-image>" (use the uncompressed version of your kernel image for the guest,  vmlinux-*)

 

To use "active-domains" you need to run opcontrol in the guest in addition to running it in dom0 and you need to coordinate the execution of both instances.. This require the guest opcontrol to be ready before running "opcontrol --start" in dom0. That is why it is failing. I suspect you have not executed opcontrol in the guest

Using active-domains is very tricky. I suggest that you use --passive-domains, unless you really need active domains (it is only useful in case you need detailed profiles for user processes running in the guest)

 

Renato 

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From: Dante Cinco [mailto:dantecinco@xxxxxxxxx]
Sent: Monday, November 09, 2009 6:13 PM
To: Santos, Jose Renato G
Cc: Xen-users
Subject: Re: xenoprof: operation 9 failed for dom0 (status: -1)

Renato,

I've narrowed down the opcontrol command sequence that causes the "write error" I'm having. If I just run "opcontrol --start" in dom0, it runs with no error and after "opcontrol --shutdown" I can run "opreport" and get a real report.

If I run "opcontrol --start-daemon --active-domains=1" in dom0, run "opcontrol --start" in domU (ID#1) and go back to dom0 and run "opcontrol --start" I get the "write error" message. It's as if "--start-daemon" is grabbing the file handle for /dev/oprofile/enable so when "--start" tries to write "1" to /dev/oprofile/enable, it is unable to do so because it is already locked.

So I can run OProfile in normal (non-Xen) mode but as soon I start using "--start-daemon" I have problems. To me it seems like a Xenoprofile problem.

I'm using OProfile 0.9.3 and oprofile-0.9.3-xen-r2.patch applied successfully.

Dante   

On Thu, Nov 5, 2009 at 6:05 PM, Santos, Jose Renato G <joserenato.santos@xxxxxx> wrote:

What version of OProfile are you using?

Did you apply the Xen patch available in http://xenoprof.sourceforge.net ?

 

Renato

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From: Dante Cinco [mailto:dantecinco@xxxxxxxxx]
Sent: Thursday, November 05, 2009 5:16 PM
To: Santos, Jose Renato G
Cc: Xen-devel
Subject: xenoprof: operation 9 failed for dom0 (status: -1)

Renato,

When I tried running "opcontrol --start" (after previously running "opcontrol --start-daemon") in dom0, I get this error message:

/usr/local/bin/opcontrol: line 1639: echo: write error: Operation not permitted

and this message in the Xen console:

(XEN) xenoprof: operation 9 failed for dom 0 (status : -1)

It looks like opcontrol is trying to do this: echo 1 > /dev/oprofile/enable

and it is failing. "operation 9" maps to XENOPROF_start which is consistent with running "opcontrol --start." At first, I ignored the error because it gave the indication "Profiler running" but after I ran "opcontrol --shutdown" followed by "opreport" in dom0, I got this error message:

error: no sample files found: profile specification too strict ?

Do you know why the write error is occurring? I followed the steps in xenoprof_tutorial.ppt.

Dante

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