Re: [2.6.24 patch] restore blackfin HARDWARE_PM support

[Mathieu Desnoyers]

* Robin Getz (rgetz@xxxxxxxxxxxxxxxxxxxx) wrote:
> On Fri 28 Dec 2007 14:28, Mathieu Desnoyers pondered:
> > * Adrian Bunk (bunk@xxxxxxxxxx) wrote:
> > > On Fri, Dec 28, 2007 at 02:14:04PM -0500, Mathieu Desnoyers wrote:
> > > > * Adrian Bunk (adrian.bunk@xxxxxxxxx) wrote:
> > > > > This patch restores the blackfin Hardware Performance Monitor Profiling 
> > > > > support that was killed by
> > > > > commit 09cadedbdc01f1a4bea1f427d4fb4642eaa19da9.
> > > > > 
> > > > > Signed-off-by: Adrian Bunk <adrian.bunk@xxxxxxxxx>
> > > > > 
> > > > 
> > > > Yep, this one too must be put back, but kernel/Kconfig.instrumentation
> > > > seems like the wrong spot for a blackfin-specific config option (and
> > > > this will break the instrumentation menu removal patches in -mm).
> > > > 
> > > > Can we put this in arch/blackfin/Kconfig instead ?
> > > 
> > > No, this is a user visible option that belongs into the same menu as
> > > "Profling support".
> > > 
> > 
> > Actually, I wonder why these options exist at all rather than being on
> > by default when profiling is enabled. There is no such thing as
> > "activating the performance monitor profiling" on other architectures.
> > What is so special about blackfin that makes it need it ?
> 
> This is probably more historical, and you are correct - it should just be part of profiling.
> 

Ok, and do we really need to make HARDWARE_PM a tristate ? I see that
part of it must be compiled into the kernel in core .S files. Does it
really make sense for it to be a module ?

Also, op_model_bf533.c sits in the arch/blackfin/oprofile directory,
(built if HARDWARE_PM is y or m) but depends on PROFILING, not OPROFILE.
Is HARDWARE_PM useful at all without OPROFILE ?

> 
> > > > > ---
> > > > > 
> > > > >  kernel/Kconfig.instrumentation |    9 +++++++++
> > > > >  1 file changed, 9 insertions(+)
> > > > > 
> > > > > 942996f33f81726c5edb012d61ecdad70c55884d 
> > > > > diff --git a/kernel/Kconfig.instrumentation b/kernel/Kconfig.instrumentation
> > > > > index 97c76ca..e023671 100644
> > > > > --- a/kernel/Kconfig.instrumentation
> > > > > +++ b/kernel/Kconfig.instrumentation
> > > > > @@ -44,2 +44,11 @@ config OPROFILE_MPCORE
> > > > >  
> > > > > +config HARDWARE_PM
> > > > > +	tristate "Hardware Performance Monitor Profiling"
> > > > > +	depends on BLACKFIN && PROFILING
> > > > > +	help
> > > > > +	  take use of hardware performance monitor to profiling the kernel
> > > > > +	  and application.
> > > > > +
> > > > > +	  If unsure, say N.
> > > > > +
> > > > >  config KPROBES
> > > > > 
> > > > 
> > > > Mathieu Desnoyers
> > > 
> > > cu
> > > Adrian
> > > 
> > > -- 
> > > 
> > >        "Is there not promise of rain?" Ling Tan asked suddenly out
> > >         of the darkness. There had been need of rain for many days.
> > >        "Only a promise," Lao Er said.
> > >                                        Pearl S. Buck - Dragon Seed
> > > 
> > 

-- 
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68
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