Re: Questions about OProfile

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Mon, Apr 18, 2011 at 01:33:59PM -0500, W. Michael Petullo wrote:
> >>>> First, what is the status of Xenoprof? The latest patch is against 0.9.5,
> >>>> but OProfile 0.9.6 is about 16 months old. Is Xenoprof actively
> >>>> maintained?
> 
> >>> There is a crufty pv_ops patch that I forward ported to 2.6.32 in this tree:
> >>> 
> >>> https://github.com/avsm/linux-2.6.32-xen-oprofile
> 
> >> So, is it true that I need to 1) use this patch or 2) use a non-PV
> >> Ops Dom0? I thought 2.6.32 was already non-PV Ops.
>  
> > I don't understand the question. The above tree is a pv_ops kernel,
> > with additional patches applied so it can be a full Xen dom0 (including
> > netback, etc).  I'm only sporadically updating it as I need to, so you
> > probably just want the oprofile patch [1] if you want to apply it to
> > some other kernel.
> > 
> > https://github.com/avsm/linux-2.6.32-xen-oprofile/commit/4df4780e638d14249b7aa4005511218a9183c324
> 
> I ported Anil's patch to Linux 2.6.38. The result is available at:
> 
> 	http://www.flyn.org/patches/linux-2.6.38-xen-passive-oprofile/linux-2.6.38-xen-passive-oprofile.patch.gz
> 
> With this patch applied to Linux 2.6.38 (along with various orthagonal Xen
> patches), I can perform passive profiling on an unprivileged Xen domain.

Woot! Awesome. For fun I tried to stick on 2.6.39, but got this:

 patch -p1 --dry-run < ~/linux-2.6.38-xen-passive-oprofile.patch 
patching file arch/x86/include/asm/xen/hypercall.h
Hunk #1 succeeded at 447 (offset 7 lines).
patching file arch/x86/oprofile/Makefile
patching file arch/x86/oprofile/xenoprof.c
patching file arch/x86/xen/mmu.c
Hunk #1 succeeded at 2349 (offset 55 lines).
Hunk #2 succeeded at 2381 (offset 55 lines).
Hunk #3 succeeded at 2403 with fuzz 1 (offset 55 lines).
patching file drivers/oprofile/buffer_sync.c
patching file drivers/oprofile/cpu_buffer.c
Hunk #5 FAILED at 259.
Hunk #6 FAILED at 275.
Hunk #7 FAILED at 408.
Hunk #8 succeeded at 448 (offset 10 lines).
3 out of 8 hunks FAILED -- saving rejects to file drivers/oprofile/cpu_buffer.c.rej
patching file drivers/oprofile/cpu_buffer.h
patching file drivers/oprofile/event_buffer.h
patching file drivers/oprofile/oprof.c
patching file drivers/oprofile/oprof.h
patching file drivers/oprofile/oprofile_files.c
patching file drivers/xen/xenoprof/xenoprofile.c
patching file include/linux/oprofile.h
Hunk #4 succeeded at 130 (offset 7 lines).
patching file include/xen/interface/xen.h
patching file include/xen/interface/xenoprof.h
patching file include/xen/xenoprof.h
patching file include/xen/xen-ops.h


And looking at the code it would require some little help in cpu_buffer
depatment.

It definitly has a lot of #ifdef CONFIG_XEN in it.. you wouldn't be
by any chance signing up for also trying to upstream it?