Messages in this thread | | | Date | Fri, 23 Oct 2015 15:27:02 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH v2 05/10] hwmon: (fam15h_power) Add compute unit accumulated power |
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On Tue, Oct 20, 2015 at 10:28:24AM +0800, 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@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]));
I guess the WARN_ON's here should be WARN_ON_ONCE() - otherwise dmesg is filling up very quickly.
> +} > + > +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();
This should be get_online_cpus() and its counterpart below should be put_online_cpus().
> + > + /* > + * Choose the first online core of each compute unit, and then > + * read their MSR value of power and ptsc in one time of IPI,
in a single IPI.
> + * because the MSR value of cpu core represent the compute
s/cpu/CPU/
do that in *all* your text.
> + * unit's. This behavior can decrease IPI numbers between the
unit's ?
What does that sentence even mean?
> + * 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); > + }
This is hard to parse - I *think* you're setting a bit in mask for a core in each CU...
If so, I think you can simplify it by generating a tmp mask which contains the cores of CU0, i.e. something like that:
11_00_00_...
and then do cpumask_and(res, ...) to find the online cores on that CU and then do cpumask_set_cpu(cpumask_any(res), mask) to select one CPU on that CU.
And then shift to the next CU:
cpumask_shift_right(dst, src_mask, cores_per_cu);
I think this should be cleaner and less error prone, without the conditionals...
> + > + 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;
Simply:
return read_registers(data);
> } > > static int fam15h_power_probe(struct pci_dev *pdev, > -- > 1.9.1 >
-- Regards/Gruss, Boris.
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg) --
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