On Fri, Dec 16, 2022 at 05:24:08PM -0300, Marcelo Tosatti wrote: > The coretemp driver uses rdmsr_on_cpu calls to read > MSR_IA32_PACKAGE_THERM_STATUS/MSR_IA32_THERM_STATUS registers, > which contain information about current core temperature. > > For certain low latency applications, the RDMSR interruption exceeds > the applications requirements. > > So do not create core files in sysfs, for CPUs which have > isolation and nohz_full enabled. > > Temperature information from the housekeeping cores should be > sufficient to infer die temperature. > > Signed-off-by: Marcelo Tosatti <mtosatti@xxxxxxxxxx> Applied to hwmon-next. Thanks, Guenter > --- > v3: do not create sysfs files for isolated CPUs (Guenter Roeck) > v2: improve changelog to mention that an error is returned, > and sysfs file is not disabled (Guenter Roeck) > > diff --git a/drivers/hwmon/coretemp.c b/drivers/hwmon/coretemp.c > index 9bee4d33fbdf..619dfde7a712 100644 > --- a/drivers/hwmon/coretemp.c > +++ b/drivers/hwmon/coretemp.c > @@ -27,6 +27,7 @@ > #include <asm/msr.h> > #include <asm/processor.h> > #include <asm/cpu_device_id.h> > +#include <linux/sched/isolation.h> > > #define DRVNAME "coretemp" > > @@ -458,6 +459,9 @@ static int create_core_data(struct platform_device *pdev, unsigned int cpu, > u32 eax, edx; > int err, index, attr_no; > > + if (!housekeeping_cpu(cpu, HK_TYPE_MISC)) > + return 0; > + > /* > * Find attr number for sysfs: > * We map the attr number to core id of the CPU
