Re: [PATCH v4] x86, sched: Fix the AMD CPPC maximum perf on some specific generations

[Ingo Molnar]

* Alexander Monakov <amonakov@xxxxxxxxx> wrote:

> On Sun, 25 Apr 2021, Huang Rui wrote:
> 
> > Some AMD Ryzen generations has different calculation method on maximum
> > perf. 255 is not for all asics, some specific generations should use 166
> > as the maximum perf. Otherwise, it will report incorrect frequency value
> > like below:
> 
> The commit message says '255', but the code:
> 
> > --- a/arch/x86/kernel/cpu/amd.c
> > +++ b/arch/x86/kernel/cpu/amd.c
> > @@ -1170,3 +1170,19 @@ void set_dr_addr_mask(unsigned long mask, int dr)
> >  		break;
> >  	}
> >  }
> > +
> > +u32 amd_get_highest_perf(void)
> > +{
> > +	struct cpuinfo_x86 *c = &boot_cpu_data;
> > +
> > +	if (c->x86 == 0x17 && ((c->x86_model >= 0x30 && c->x86_model < 0x40) ||
> > +			       (c->x86_model >= 0x70 && c->x86_model < 0x80)))
> > +	    return 166;
> > +
> > +	if (c->x86 == 0x19 && ((c->x86_model >= 0x20 && c->x86_model < 0x30) ||
> > +			       (c->x86_model >= 0x40 && c->x86_model < 0x70)))
> > +	    return 166;
> > +
> > +	return 225;
> > +}
> 
> says 225? This is probably a typo? In any case they are out of sync.
> 
> Alexander

Ugh - that's indeed a good question ...

Thanks,

	Ingo