On 03/10/2016 06:17 PM, Huang Rui wrote:
This patch adds a member in fam15h_power_data which specifies the compute unit accumulated power. It adds do_read_registers_on_cu to do all the read to all MSRs and run it on one of the online cores on each compute unit with smp_call_function_many(). This behavior can decrease IPI numbers. Suggested-by: Borislav Petkov <bp@xxxxxxxxx> Signed-off-by: Huang Rui <ray.huang@xxxxxxx> --- drivers/hwmon/fam15h_power.c | 61 +++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 60 insertions(+), 1 deletion(-) diff --git a/drivers/hwmon/fam15h_power.c b/drivers/hwmon/fam15h_power.c index 4f695d8..c5e2297 100644 --- a/drivers/hwmon/fam15h_power.c +++ b/drivers/hwmon/fam15h_power.c @@ -25,6 +25,8 @@ #include <linux/module.h> #include <linux/pci.h> #include <linux/bitops.h> +#include <linux/cpu.h> +#include <linux/cpumask.h> #include <asm/processor.h> #include <asm/msr.h> @@ -44,7 +46,9 @@ MODULE_LICENSE("GPL"); #define FAM15H_MIN_NUM_ATTRS 2 #define FAM15H_NUM_GROUPS 2 +#define MAX_CUS 8 +#define MSR_F15H_CU_PWR_ACCUMULATOR 0xc001007a #define MSR_F15H_CU_MAX_PWR_ACCUMULATOR 0xc001007b #define PCI_DEVICE_ID_AMD_15H_M70H_NB_F4 0x15b4 @@ -59,6 +63,8 @@ struct fam15h_power_data { struct attribute_group group; /* maximum accumulated power of a compute unit */ u64 max_cu_acc_power; + /* accumulated power of the compute units */ + u64 cu_acc_power[MAX_CUS]; }; static ssize_t show_power(struct device *dev, @@ -125,6 +131,59 @@ static ssize_t show_power_crit(struct device *dev, } static DEVICE_ATTR(power1_crit, S_IRUGO, show_power_crit, NULL); +static void do_read_registers_on_cu(void *_data) +{ + struct fam15h_power_data *data = _data; + int cpu, cu; + + cpu = smp_processor_id(); + + cu = cpu / smp_num_siblings; +
If smp is not configured: drivers/hwmon/fam15h_power.c: In function ‘do_read_registers_on_cu’: drivers/hwmon/fam15h_power.c:144:13: error: ‘smp_num_siblings’ undeclared (first use in this function) Guenter
+ rdmsrl_safe(MSR_F15H_CU_PWR_ACCUMULATOR, &data->cu_acc_power[cu]); +} + +/* + * This function is only able to be called when CPUID + * Fn8000_0007:EDX[12] is set. + */ +static int read_registers(struct fam15h_power_data *data) +{ + int this_cpu, ret, cpu; + int target; + cpumask_var_t mask; + + ret = zalloc_cpumask_var(&mask, GFP_KERNEL); + if (!ret) + return -ENOMEM; + + get_online_cpus(); + this_cpu = get_cpu(); + + /* + * Choose the first online core of each compute unit, and then + * read their MSR value of power and ptsc in a single IPI, + * because the MSR value of CPU core represent the compute + * unit's. + */ + for_each_online_cpu(cpu) { + target = cpumask_first(topology_sibling_cpumask(cpu)); + if (!cpumask_test_cpu(target, mask)) + cpumask_set_cpu(target, mask); + } + + if (cpumask_test_cpu(this_cpu, mask)) + do_read_registers_on_cu(data); + + smp_call_function_many(mask, do_read_registers_on_cu, data, true); + put_cpu(); + put_online_cpus(); + + free_cpumask_var(mask); + + return 0; +} + static int fam15h_power_init_attrs(struct pci_dev *pdev, struct fam15h_power_data *data) { @@ -263,7 +322,7 @@ static int fam15h_power_init_data(struct pci_dev *f4, data->max_cu_acc_power = tmp; - return 0; + return read_registers(data); } static int fam15h_power_probe(struct pci_dev *pdev,
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