Hi Stephane,
Well, I guess this is a little better. ;-) I was just hoping to
agree on what PLM level is kernel mode...
Now I have this in my PAPI code, it's kind of gross IMHO.
if (domain & PAPI_DOM_KERNEL) {
#if defined(mips)
mode |= PFM_PLM2;
#elif defined(ia64) || defined(i386) || defined(x86_64)
mode |= PFM_PLM0;
#else
#error "Unknown PLM mapping for this architecture for KERNEL MODE."
#endif
}
Whereas, if PLM2 was kernel and was always kernel, the above code would
be clean.
Anyways, I appreciate the cleanup. I understand the abstraction from the
semantics, but I like conventions...this is probably just a matter of
opinion.
Regards,
Phil
On Sun, 2006-07-23 at 08:48 -0700, Stephane Eranian wrote:
> Phil,
>
> On Sun, Jul 23, 2006 at 12:21:00PM +0200, Philip Mucci wrote:
> > Hi Stefane,
> >
> > I think sensible interpretations are A Good Thing for APIs, don't you
> > agree?
> >
> Yes.
>
> > This would mean a change to both the code for I386 and IA64, to make
> > PFM_PLM0 be kernel mode. At the moment, the only way to figure out what
> > is what for any given platform is to dig through the source.
>
> In libpfm today, each PMU specific module is responsible for interpreting
> the meaning of PFM_PLM*. Yet the definition of the macros is in the
> generic pfmlib.h file (the is useful for building generic test/example
> programs).
> The associated comments, though, are not generic. Based on your comments, I
> have made
> some changes. The generic header (pfmlib.h) does not provide any
> intepretation,
> it just lists 4 levels. Then you document in each arch/pmu specific header
> file how the levels are interpreted. I have pushed this into CVS now.
> I provided the interpretation for MIPS, hope this is correct.
>
> Tell me if you are more conformtable with this model?
>
> Thanks.
>
> >
> > Anyways, this is just a suggestion. I work with the sources, so there's
> > no problem for me. But I believe that not having any standardized
> > meaning for PFM_PLMs when there most certainly are standardized
> > definitions of SUPERVISOR, INTERRUPT, KERNEL and USER modes is a bit of
> > a mistake.
> >
> > At the very least, we should change the kernel comment in the header
> > file. But currently, the comments are just wrong, kernel mode isn't hre
> > most privileged and this confuses things for PPC64, MIPS and
> > virtualizable implementations of the x86/x86_64 and IA64.
> >
> > Anyways, just a suggestion.
> >
> > Phil
> >
> >
> >
> > On Fri, 2006-07-21 at 13:01 -0700, Stephane Eranian wrote:
> > > Phil,
> > >
> > > Using the PFM_PLM* is just a matter of interpretation for your platform.
> > >
> > > For what I can see from your proposal you have not changed anything
> > > to the existing code. You just changed the comments (interpretation).
> > > The good thing about using a numbering scheme as opposed to
> > > explicit names (e.g, KERNEL, INTR, USR, ...) is that it is up
> > > to each platform to map this to their actual priv levels.
> > >
> > >
> > > On Fri, Jul 21, 2006 at 01:21:08PM +0200, Philip Mucci wrote:
> > > > Hi folks,
> > > >
> > > > Would people care to standardize the definitions of PFM_PLM?
> > > >
> > > > Currently they are different for different architectures. This isn't so
> > > > much of an issue on x86, but on PPC64, MIPS and others that have
> > > > hypervisor modes, it seems like we should go from this:
> > > >
> > > > libpfm-3.x/include/perfmon/pfmlib.h:#define PFM_PLM0
> > > > 0x1 /* kernel level (most privileged) */
> > > > libpfm-3.x/include/perfmon/pfmlib.h:#define PFM_PLM1
> > > > 0x2 /* priv level 1 */
> > > > libpfm-3.x/include/perfmon/pfmlib.h:#define PFM_PLM2
> > > > 0x4 /* priv level 2 */
> > > > libpfm-3.x/include/perfmon/pfmlib.h:#define PFM_PLM3
> > > > 0x8 /* user level (least privileged) */
> > > >
> > > >
> > > > To this:
> > > >
> > > > libpfm-3.x/include/perfmon/pfmlib.h:#define PFM_PLM0
> > > > 0x1 /* supervisor level (most privileged) */
> > > > libpfm-3.x/include/perfmon/pfmlib.h:#define PFM_PLM1
> > > > 0x2 /* interrupt level */
> > > > libpfm-3.x/include/perfmon/pfmlib.h:#define PFM_PLM2
> > > > 0x4 /* kernel level */
> > > > libpfm-3.x/include/perfmon/pfmlib.h:#define PFM_PLM3
> > > > 0x8 /* user level (least privileged) */
> > > >
> > > > To change this in the current base would simply mean altering some low
> > > > level code in PFM. MIPS is currently the latter since it supports all
> > > > modes.
> > > >
> > > > Comments?
> > > >
> > > > Phil
> > > >
> > > >
> > > > _______________________________________________
> > > > perfmon mailing list
> > > > [email protected]
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> > >
> >
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>
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