Messages in this thread | | | Subject | Re: [PATCH 2/4] x86, sched: Account for CPUs with less than 4 cores in freq. invariance | From | Dave Kleikamp <> | Date | Thu, 16 Apr 2020 10:26:36 -0500 |
| |
On 4/16/20 12:47 AM, Giovanni Gherdovich wrote: > If a CPU has less than 4 physical cores, MSR_TURBO_RATIO_LIMIT will > rightfully report that the 4C turbo ratio is zero. In such cases, use the > 1C turbo ratio instead for frequency invariance calculations.
Thank you! This makes my Lenovo T410 happy again. I had tracked down the problem and come up with a similar patch. I was about to report it when I came across this patch set.
> > Reported-by: Neil Rickert <nwr10cst-oslnx@yahoo.com> > Reported-by: Like Xu <like.xu@linux.intel.com> > Signed-off-by: Giovanni Gherdovich <ggherdovich@suse.cz> > Fixes: 1567c3e3467c ("x86, sched: Add support for frequency invariance")
Tested-by: Dave Kleikamp <dave.kleikamp@oracle.com>
> --- > arch/x86/kernel/smpboot.c | 11 ++++++++--- > 1 file changed, 8 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c > index 3a318ec9bc17..5d346b70844b 100644 > --- a/arch/x86/kernel/smpboot.c > +++ b/arch/x86/kernel/smpboot.c > @@ -1945,18 +1945,23 @@ static bool skx_set_max_freq_ratio(u64 *base_freq, u64 *turbo_freq, int size) > > static bool core_set_max_freq_ratio(u64 *base_freq, u64 *turbo_freq) > { > + u64 msr; > int err; > > err = rdmsrl_safe(MSR_PLATFORM_INFO, base_freq); > if (err) > return false; > > - err = rdmsrl_safe(MSR_TURBO_RATIO_LIMIT, turbo_freq); > + err = rdmsrl_safe(MSR_TURBO_RATIO_LIMIT, &msr); > if (err) > return false; > > - *base_freq = (*base_freq >> 8) & 0xFF; /* max P state */ > - *turbo_freq = (*turbo_freq >> 24) & 0xFF; /* 4C turbo */ > + *base_freq = (*base_freq >> 8) & 0xFF; /* max P state */ > + *turbo_freq = (msr >> 24) & 0xFF; /* 4C turbo */ > + > + /* The CPU may have less than 4 cores */ > + if (!*turbo_freq) > + *turbo_freq = msr & 0xFF; /* 1C turbo */ > > return true; > } >
| |