On Thu, 04 Dec 2014 23:10:58 +0100
"Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx> wrote:
> On Thursday, December 04, 2014 11:07:31 AM Ethan Zhao wrote:
> > To force loading on Oracle Sun X86 servers, provide one kernel command line
> > parameter
> >
> > intel_pstate = ora_force
>
> I would suggest to change the name of the option to "oracle_force" or "sun_force"
> for clarity.
>
> Anyway, I need an ACK from Kristen if this patch is to be applied.
>
> > For those who be aware of the risk of no power capping capabily working and
> > try to get better performance with this driver.
> >
> > Signed-off-by: Ethan Zhao <ethan.zhao@xxxxxxxxxx>
> > ---
> > v2: change to hardware vendor specific naming parameter.
> > v4: refine code and doc.
> > v5&v6: fix a typo in doc.
> > v7: change enum PCC to PPC.
> >
> > Documentation/kernel-parameters.txt | 5 +++++
> > drivers/cpufreq/intel_pstate.c | 6 +++++-
> > 2 files changed, 10 insertions(+), 1 deletion(-)
> >
> > diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
> > index 479f332..7d0983e 100644
> > --- a/Documentation/kernel-parameters.txt
> > +++ b/Documentation/kernel-parameters.txt
> > @@ -1446,6 +1446,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
> > disable
> > Do not enable intel_pstate as the default
> > scaling driver for the supported processors
> > + ora_force
> > + Force loading intel_pstate on Oracle Sun Servers(X86).
> > + only for those who be aware of the risk of no power capping
> > + capability working and try to get better performance with this
> > + driver.
>
> That is not sufficiently clear. What does "risk of no power capping capability
> working" mean, in particular?
>
> >
> > intremap= [X86-64, Intel-IOMMU]
> > on enable Interrupt Remapping (default)
> > diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
> > index 1bb62ca..2654e13 100644
> > --- a/drivers/cpufreq/intel_pstate.c
> > +++ b/drivers/cpufreq/intel_pstate.c
> > @@ -866,6 +866,7 @@ static struct cpufreq_driver intel_pstate_driver = {
> > };
> >
> > static int __initdata no_load;
> > +static unsigned int ora_force;
> >
> > static int intel_pstate_msrs_not_valid(void)
> > {
> > @@ -1003,7 +1004,8 @@ static bool intel_pstate_platform_pwr_mgmt_exists(void)
> > case PSS:
> > return intel_pstate_no_acpi_pss();
> > case PPC:
> > - return intel_pstate_has_acpi_ppc();
> > + return intel_pstate_has_acpi_ppc() &&
> > + (!ora_force);
> > }
> > }
> >
> > @@ -1078,6 +1080,8 @@ static int __init intel_pstate_setup(char *str)
> >
> > if (!strcmp(str, "disable"))
> > no_load = 1;
> > + if (!strcmp(str, "ora_force"))
> > + ora_force = 1;
> > return 0;
> > }
> > early_param("intel_pstate", intel_pstate_setup);
>
> And can anyone please remind me what was wrong with a "force" option that would
> work for everyone, not just Oracle/Sun?
>
That was my suggestion as well (i.e. a parameter to bypass the vendor
checks), but Linda didn't like it. My personal opinion is that unless
it's generic, I don't really feel like having a force option solely for
oracle. I'm not convinced you want this for production machines, and I
think for debug purposes I don't want a vendor specific param.
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