RE: [PATCH v2 07/14] cpufreq: amd_pstate: map desired perf into pstate scope for powersave governor

[Yuan, Perry]

[AMD Official Use Only - General]

Hi Nathan.

> -----Original Message-----
> From: Fontenot, Nathan <Nathan.Fontenot@xxxxxxx>
> Sent: Tuesday, July 12, 2022 3:34 AM
> To: Yuan, Perry <Perry.Yuan@xxxxxxx>; rafael.j.wysocki@xxxxxxxxx;
> viresh.kumar@xxxxxxxxxx; Huang, Ray <Ray.Huang@xxxxxxx>
> Cc: Sharma, Deepak <Deepak.Sharma@xxxxxxx>; Limonciello, Mario
> <Mario.Limonciello@xxxxxxx>; Fontenot, Nathan
> <Nathan.Fontenot@xxxxxxx>; Deucher, Alexander
> <Alexander.Deucher@xxxxxxx>; Su, Jinzhou (Joe) <Jinzhou.Su@xxxxxxx>;
> Huang, Shimmer <Shimmer.Huang@xxxxxxx>; Du, Xiaojian
> <Xiaojian.Du@xxxxxxx>; Meng, Li (Jassmine) <Li.Meng@xxxxxxx>; linux-
> pm@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v2 07/14] cpufreq: amd_pstate: map desired perf into
> pstate scope for powersave governor
> 
> On 7/9/22 09:19, Perry Yuan wrote:
> > The patch will fix the invalid desired perf value for powersave
> > governor. This issue is found when testing on one AMD EPYC system, the
> > actual des_perf is smaller than the min_perf value, that is invalid
> > value. because the min_perf is the lowest_perf system can support in
> > idle state.
> >
> > Signed-off-by: Perry Yuan <Perry.Yuan@xxxxxxx>
> > ---
> >  drivers/cpufreq/amd-pstate.c | 1 +
> >  1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/cpufreq/amd-pstate.c
> > b/drivers/cpufreq/amd-pstate.c index 7c51f4125263..8a2b6ad9b8c0
> 100644
> > --- a/drivers/cpufreq/amd-pstate.c
> > +++ b/drivers/cpufreq/amd-pstate.c
> > @@ -265,6 +265,7 @@ static void amd_pstate_update(struct
> amd_cpudata *cpudata, u32 min_perf,
> >  	u64 prev = READ_ONCE(cpudata->cppc_req_cached);
> >  	u64 value = prev;
> >
> > +	des_perf = clamp_t(unsigned long, des_perf, min_perf, max_perf);
> 
> You should also update amd_pstate_adjust_perf() to remove the clamp_t()
> call now that it is done here.
> 
> -Nathan

I missed that, changed into V3.
Thank you!

Perry.
> 
> >  	value &= ~AMD_CPPC_MIN_PERF(~0L);
> >  	value |= AMD_CPPC_MIN_PERF(min_perf);
> >