From 0f8b916bc5b5d74cacef2b616b04db10633b8105 Mon Sep 17 00:00:00 2001 From: Marcelo Tosatti Date: Fri, 16 Dec 2022 17:24:08 -0300 Subject: [PATCH] hwmon: (coretemp) avoid RDMSR interrupts to isolated CPUs 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 Link: https://lore.kernel.org/r/Y5zT6B1mY9/pnwJV@tpad Signed-off-by: Guenter Roeck --- drivers/hwmon/coretemp.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/hwmon/coretemp.c b/drivers/hwmon/coretemp.c index ca7a9b3..49091ea 100644 --- a/drivers/hwmon/coretemp.c +++ b/drivers/hwmon/coretemp.c @@ -27,6 +27,7 @@ #include #include #include +#include #define DRVNAME "coretemp" @@ -502,6 +503,9 @@ 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 -- 2.7.4