Messages in this thread | | | Date | Mon, 13 Jan 2020 15:34:30 +0100 | From | Greg KH <> | Subject | Re: [PATCH v3 1/2] perf x86: Infrastructure for exposing an Uncore unit to PMON mapping |
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On Mon, Jan 13, 2020 at 04:54:43PM +0300, roman.sudarikov@linux.intel.com wrote: > From: Roman Sudarikov <roman.sudarikov@linux.intel.com> > > Intel® Xeon® Scalable processor family (code name Skylake-SP) makes > significant changes in the integrated I/O (IIO) architecture. The new > solution introduces IIO stacks which are responsible for managing traffic > between the PCIe domain and the Mesh domain. Each IIO stack has its own > PMON block and can handle either DMI port, x16 PCIe root port, MCP-Link > or various built-in accelerators. IIO PMON blocks allow concurrent > monitoring of I/O flows up to 4 x4 bifurcation within each IIO stack. > > Software is supposed to program required perf counters within each IIO > stack and gather performance data. The tricky thing here is that IIO PMON > reports data per IIO stack but users have no idea what IIO stacks are - > they only know devices which are connected to the platform. > > Understanding IIO stack concept to find which IIO stack that particular > IO device is connected to, or to identify an IIO PMON block to program > for monitoring specific IIO stack assumes a lot of implicit knowledge > about given Intel server platform architecture. > > Usage example: > /sys/devices/uncore_<type>_<pmu_idx>/platform_mapping > > Each Uncore unit type, by its nature, can be mapped to its own context, > for example: > 1. CHA - each uncore_cha_<pmu_idx> is assigned to manage a distinct slice > of LLC capacity; > 2. UPI - each uncore_upi_<pmu_idx> is assigned to manage one link of Intel > UPI Subsystem; > 3. IIO - each uncore_iio_<pmu_idx> is assigned to manage one stack of the > IIO module; > 4. IMC - each uncore_imc_<pmu_idx> is assigned to manage one channel of > Memory Controller. > > Implementation details: > Two callbacks added to struct intel_uncore_type to discover and map Uncore > units to PMONs: > int (*get_topology)(void) > int (*set_mapping)(struct intel_uncore_pmu *pmu) > > Details of IIO Uncore unit mapping to IIO PMON: > Each IIO stack is either DMI port, x16 PCIe root port, MCP-Link or various > built-in accelerators. For Uncore IIO Unit type, the platform_mapping file > holds bus numbers of devices, which can be monitored by that IIO PMON block > on each die. > > Co-developed-by: Alexander Antonov <alexander.antonov@intel.com> > Reviewed-by: Kan Liang <kan.liang@linux.intel.com> > Signed-off-by: Alexander Antonov <alexander.antonov@intel.com> > Signed-off-by: Roman Sudarikov <roman.sudarikov@linux.intel.com> > --- > arch/x86/events/intel/uncore.c | 37 +++++++++++++++++++++++++++++++++- > arch/x86/events/intel/uncore.h | 9 ++++++++- > 2 files changed, 44 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/events/intel/uncore.c b/arch/x86/events/intel/uncore.c > index 86467f85c383..2c53ad44b51f 100644 > --- a/arch/x86/events/intel/uncore.c > +++ b/arch/x86/events/intel/uncore.c > @@ -905,6 +905,32 @@ static void uncore_types_exit(struct intel_uncore_type **types) > uncore_type_exit(*types); > } > > +static struct attribute *empty_attrs[] = { > + NULL, > +}; > + > +static const struct attribute_group empty_group = { > + .attrs = empty_attrs, > +};
What is this for? Why is it needed? It doesn't do anything?
> + > +static ssize_t platform_mapping_show(struct device *dev, > + struct device_attribute *attr, char *buf) > +{ > + struct intel_uncore_pmu *pmu = dev_get_drvdata(dev); > + > + return snprintf(buf, PAGE_SIZE - 1, "%s\n", pmu->mapping); > +} > +static DEVICE_ATTR_RO(platform_mapping);
You are creating new sysfs attributes without any Documentation/ABI updates, which is not ok. Please fix this up for your next round of patches.
> +static struct attribute *mapping_attrs[] = { > + &dev_attr_platform_mapping.attr, > + NULL, > +}; > + > +static const struct attribute_group uncore_mapping_group = { > + .attrs = mapping_attrs, > +};
ATTRIBUTE_GROUPS()?
Messing around with single attribute_group lists is usually a sign that something is really wrong as the driver core should handle arrays of attribute group lists instead.
> + > static int __init uncore_type_init(struct intel_uncore_type *type, bool setid) > { > struct intel_uncore_pmu *pmus; > @@ -950,10 +976,19 @@ static int __init uncore_type_init(struct intel_uncore_type *type, bool setid) > attr_group->attrs[j] = &type->event_descs[j].attr.attr; > > type->events_group = &attr_group->group; > - } > + } else > + type->events_group = &empty_group;
Why???
Didn't we fix up the x86 attributes to work properly and not mess around with trying to merge groups and the like? Please don't perpetuate that more...
thanks,
greg k-h
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