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    Subject[PATCH v2 05/10] hwmon: (fam15h_power) Add compute unit accumulated power
    Date
    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@alien8.de>
    Signed-off-by: Huang Rui <ray.huang@amd.com>
    Cc: Guenter Roeck <linux@roeck-us.net>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Ingo Molnar <mingo@kernel.org>
    ---
    drivers/hwmon/fam15h_power.c | 68 +++++++++++++++++++++++++++++++++++++++++++-
    1 file changed, 67 insertions(+), 1 deletion(-)

    diff --git a/drivers/hwmon/fam15h_power.c b/drivers/hwmon/fam15h_power.c
    index e2bfab5..88e4f3e 100644
    --- a/drivers/hwmon/fam15h_power.c
    +++ b/drivers/hwmon/fam15h_power.c
    @@ -25,6 +25,7 @@
    #include <linux/module.h>
    #include <linux/pci.h>
    #include <linux/bitops.h>
    +#include <linux/cpumask.h>
    #include <asm/processor.h>
    #include <asm/msr.h>

    @@ -44,7 +45,9 @@ 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

    struct fam15h_power_data {
    @@ -57,6 +60,8 @@ struct fam15h_power_data {
    struct attribute_group fam15h_power_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,
    @@ -115,6 +120,65 @@ 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, cores_per_cu;
    +
    + cpu = smp_processor_id();
    +
    + cores_per_cu = amd_get_cores_per_cu();
    + cu = cpu / cores_per_cu;
    +
    + WARN_ON(rdmsrl_safe(MSR_F15H_CU_PWR_ACCUMULATOR,
    + &data->cu_acc_power[cu]));
    +}
    +
    +static int read_registers(struct fam15h_power_data *data)
    +{
    + int this_cpu, ret;
    + int cu_num, cores_per_cu, cpu, cu;
    + cpumask_var_t mask;
    +
    + cores_per_cu = amd_get_cores_per_cu();
    + cu_num = boot_cpu_data.x86_max_cores / cores_per_cu;
    +
    + WARN_ON_ONCE(cu_num > MAX_CUS);
    +
    + ret = zalloc_cpumask_var(&mask, GFP_KERNEL);
    + if (!ret)
    + return -ENOMEM;
    +
    + this_cpu = get_cpu();
    +
    + /*
    + * Choose the first online core of each compute unit, and then
    + * read their MSR value of power and ptsc in one time of IPI,
    + * because the MSR value of cpu core represent the compute
    + * unit's. This behavior can decrease IPI numbers between the
    + * cores.
    + */
    + cpu = cpumask_first(cpu_online_mask);
    + cu = cpu / cores_per_cu;
    + while (cpu < boot_cpu_data.x86_max_cores) {
    + if (cu <= cpu / cores_per_cu) {
    + cu = cpu / cores_per_cu + 1;
    + cpumask_set_cpu(cpu, mask);
    + }
    + cpu = cpumask_next(cu * cores_per_cu - 1, cpu_online_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();
    +
    + free_cpumask_var(mask);
    +
    + return 0;
    +}
    +
    static int fam15h_power_init_attrs(struct pci_dev *pdev,
    struct fam15h_power_data *data)
    {
    @@ -253,7 +317,9 @@ static int fam15h_power_init_data(struct pci_dev *f4,

    data->max_cu_acc_power = tmp;

    - return 0;
    + ret = read_registers(data);
    +
    + return ret;
    }

    static int fam15h_power_probe(struct pci_dev *pdev,
    --
    1.9.1


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