[PATCH 22/37] drm/amdkfd: Add perf counters to topology

Felix Kühling felix.kuehling at gmail.com
Sat Dec 16 20:48:01 UTC 2017


Am 12.12.2017 um 09:15 schrieb Oded Gabbay:
> On Mon, Dec 11, 2017 at 9:54 PM, Felix Kuehling <felix.kuehling at amd.com> wrote:
>> On 2017-12-11 10:23 AM, Oded Gabbay wrote:
>>> On Sat, Dec 9, 2017 at 6:09 AM, Felix Kuehling <Felix.Kuehling at amd.com> wrote:
>>>> From: Amber Lin <Amber.Lin at amd.com>
>>>>
>>>> For hardware blocks whose performance counters are accessed via MMIO
>>>> registers, KFD provides the support for those privileged blocks. IOMMU is
>>>> one of those privileged blocks. Most performance counter properties
>>>> required by Thunk are available at /sys/bus/event_source/devices/amd_iommu.
>>>>  This patch adds properties to topology in KFD sysfs for information not
>>>> available in /sys/bus/event_source/devices/amd_iommu. They are shown at
>>>> /sys/devices/virtual/kfd/kfd/topology/nodes/0/perf/iommu/ formatted as
>>>> /sys/devices/virtual/kfd/kfd/topology/nodes/0/perf/<block>/<property>, i.e.
>>>> /sys/devices/virtual/kfd/kfd/topology/nodes/0/perf/iommu/max_concurrent.
>>>> For dGPUs, who don't have IOMMU, nothing appears under
>>>> /sys/devices/virtual/kfd/kfd/topology/nodes/0/perf.
>>> I don't feel comfortable with this patch. It seems to me you didn't
>>> have anywhere to put these counters so you just stuck them in a place
>>> the thunk already reads because it was "convenient" for you to do it.
>>> But, as you point out in a comment later, these counters have nothing
>>> to do with topology.
>>> So this just feels wrong and I would like to:
>>>
>>> a. get additional opinions on it. Christian ? Alex ? What do you think
>>> ? How the GPU's GFX counters are exposed ?
>>> b. Ask why not use IOCTL to get the counters ?
>> I see the performance counter information similar to other information
>> provided in the topology, such as memory, caches, CUs, etc. That's why
>> it makes sense for me to report it in the topology.
>>
>> If this is controversial, I can drop the patch for now. It's not
>> critically needed for enabling dGPU support.
>>
>> Regards,
>>   Felix
> Felix,
> Is the perf counter information part of the snapshot that the thunk
> takes before opening the device, or is it constantly being sampled ?
> If its a oneshot thing, than I think that's somehow acceptable.

It's currently read in hsaKmtOpen. But I think that could be changed to
be done as part of the snapshot. Either way, it's a one-shot thing.

Regards,
  Felix

>
> Oded
>
>>> btw, I tried to search for other drivers that do this (expose perf
>>> counters in sysfs) and didn't find any (it wasn't an exhaustive search
>>> so I may have missed).
>>>
>>> Thanks,
>>> Oded
>>>
>>>
>>>
>>>
>>>> Signed-off-by: Amber Lin <Amber.Lin at amd.com>
>>>> Signed-off-by: Kent Russell <kent.russell at amd.com>
>>>> Signed-off-by: Felix Kuehling <Felix.Kuehling at amd.com>
>>>> ---
>>>>  drivers/gpu/drm/amd/amdkfd/kfd_topology.c | 116 +++++++++++++++++++++++++++++-
>>>>  drivers/gpu/drm/amd/amdkfd/kfd_topology.h |  13 ++++
>>>>  2 files changed, 127 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_topology.c b/drivers/gpu/drm/amd/amdkfd/kfd_topology.c
>>>> index 7fe7ee0..52d20f5 100644
>>>> --- a/drivers/gpu/drm/amd/amdkfd/kfd_topology.c
>>>> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_topology.c
>>>> @@ -104,6 +104,7 @@ static void kfd_release_topology_device(struct kfd_topology_device *dev)
>>>>         struct kfd_mem_properties *mem;
>>>>         struct kfd_cache_properties *cache;
>>>>         struct kfd_iolink_properties *iolink;
>>>> +       struct kfd_perf_properties *perf;
>>>>
>>>>         list_del(&dev->list);
>>>>
>>>> @@ -128,6 +129,13 @@ static void kfd_release_topology_device(struct kfd_topology_device *dev)
>>>>                 kfree(iolink);
>>>>         }
>>>>
>>>> +       while (dev->perf_props.next != &dev->perf_props) {
>>>> +               perf = container_of(dev->perf_props.next,
>>>> +                               struct kfd_perf_properties, list);
>>>> +               list_del(&perf->list);
>>>> +               kfree(perf);
>>>> +       }
>>>> +
>>>>         kfree(dev);
>>>>  }
>>>>
>>>> @@ -162,6 +170,7 @@ struct kfd_topology_device *kfd_create_topology_device(
>>>>         INIT_LIST_HEAD(&dev->mem_props);
>>>>         INIT_LIST_HEAD(&dev->cache_props);
>>>>         INIT_LIST_HEAD(&dev->io_link_props);
>>>> +       INIT_LIST_HEAD(&dev->perf_props);
>>>>
>>>>         list_add_tail(&dev->list, device_list);
>>>>
>>>> @@ -328,6 +337,39 @@ static struct kobj_type cache_type = {
>>>>         .sysfs_ops = &cache_ops,
>>>>  };
>>>>
>>>> +/****** Sysfs of Performance Counters ******/
>>>> +
>>>> +struct kfd_perf_attr {
>>>> +       struct kobj_attribute attr;
>>>> +       uint32_t data;
>>>> +};
>>>> +
>>>> +static ssize_t perf_show(struct kobject *kobj, struct kobj_attribute *attrs,
>>>> +                       char *buf)
>>>> +{
>>>> +       struct kfd_perf_attr *attr;
>>>> +
>>>> +       buf[0] = 0;
>>>> +       attr = container_of(attrs, struct kfd_perf_attr, attr);
>>>> +       if (!attr->data) /* invalid data for PMC */
>>>> +               return 0;
>>>> +       else
>>>> +               return sysfs_show_32bit_val(buf, attr->data);
>>>> +}
>>>> +
>>>> +#define KFD_PERF_DESC(_name, _data)                    \
>>>> +{                                                      \
>>>> +       .attr  = __ATTR(_name, 0444, perf_show, NULL),  \
>>>> +       .data = _data,                                  \
>>>> +}
>>>> +
>>>> +static struct kfd_perf_attr perf_attr_iommu[] = {
>>>> +       KFD_PERF_DESC(max_concurrent, 0),
>>>> +       KFD_PERF_DESC(num_counters, 0),
>>>> +       KFD_PERF_DESC(counter_ids, 0),
>>>> +};
>>>> +/****************************************/
>>>> +
>>>>  static ssize_t node_show(struct kobject *kobj, struct attribute *attr,
>>>>                 char *buffer)
>>>>  {
>>>> @@ -452,6 +494,7 @@ static void kfd_remove_sysfs_node_entry(struct kfd_topology_device *dev)
>>>>         struct kfd_iolink_properties *iolink;
>>>>         struct kfd_cache_properties *cache;
>>>>         struct kfd_mem_properties *mem;
>>>> +       struct kfd_perf_properties *perf;
>>>>
>>>>         if (dev->kobj_iolink) {
>>>>                 list_for_each_entry(iolink, &dev->io_link_props, list)
>>>> @@ -488,6 +531,16 @@ static void kfd_remove_sysfs_node_entry(struct kfd_topology_device *dev)
>>>>                 dev->kobj_mem = NULL;
>>>>         }
>>>>
>>>> +       if (dev->kobj_perf) {
>>>> +               list_for_each_entry(perf, &dev->perf_props, list) {
>>>> +                       kfree(perf->attr_group);
>>>> +                       perf->attr_group = NULL;
>>>> +               }
>>>> +               kobject_del(dev->kobj_perf);
>>>> +               kobject_put(dev->kobj_perf);
>>>> +               dev->kobj_perf = NULL;
>>>> +       }
>>>> +
>>>>         if (dev->kobj_node) {
>>>>                 sysfs_remove_file(dev->kobj_node, &dev->attr_gpuid);
>>>>                 sysfs_remove_file(dev->kobj_node, &dev->attr_name);
>>>> @@ -504,8 +557,10 @@ static int kfd_build_sysfs_node_entry(struct kfd_topology_device *dev,
>>>>         struct kfd_iolink_properties *iolink;
>>>>         struct kfd_cache_properties *cache;
>>>>         struct kfd_mem_properties *mem;
>>>> +       struct kfd_perf_properties *perf;
>>>>         int ret;
>>>> -       uint32_t i;
>>>> +       uint32_t i, num_attrs;
>>>> +       struct attribute **attrs;
>>>>
>>>>         if (WARN_ON(dev->kobj_node))
>>>>                 return -EEXIST;
>>>> @@ -534,6 +589,10 @@ static int kfd_build_sysfs_node_entry(struct kfd_topology_device *dev,
>>>>         if (!dev->kobj_iolink)
>>>>                 return -ENOMEM;
>>>>
>>>> +       dev->kobj_perf = kobject_create_and_add("perf", dev->kobj_node);
>>>> +       if (!dev->kobj_perf)
>>>> +               return -ENOMEM;
>>>> +
>>>>         /*
>>>>          * Creating sysfs files for node properties
>>>>          */
>>>> @@ -611,7 +670,33 @@ static int kfd_build_sysfs_node_entry(struct kfd_topology_device *dev,
>>>>                 if (ret < 0)
>>>>                         return ret;
>>>>                 i++;
>>>> -}
>>>> +       }
>>>> +
>>>> +       /* All hardware blocks have the same number of attributes. */
>>>> +       num_attrs = sizeof(perf_attr_iommu)/sizeof(struct kfd_perf_attr);
>>>> +       list_for_each_entry(perf, &dev->perf_props, list) {
>>>> +               perf->attr_group = kzalloc(sizeof(struct kfd_perf_attr)
>>>> +                       * num_attrs + sizeof(struct attribute_group),
>>>> +                       GFP_KERNEL);
>>>> +               if (!perf->attr_group)
>>>> +                       return -ENOMEM;
>>>> +
>>>> +               attrs = (struct attribute **)(perf->attr_group + 1);
>>>> +               if (!strcmp(perf->block_name, "iommu")) {
>>>> +               /* Information of IOMMU's num_counters and counter_ids is shown
>>>> +                * under /sys/bus/event_source/devices/amd_iommu. We don't
>>>> +                * duplicate here.
>>>> +                */
>>>> +                       perf_attr_iommu[0].data = perf->max_concurrent;
>>>> +                       for (i = 0; i < num_attrs; i++)
>>>> +                               attrs[i] = &perf_attr_iommu[i].attr.attr;
>>>> +               }
>>>> +               perf->attr_group->name = perf->block_name;
>>>> +               perf->attr_group->attrs = attrs;
>>>> +               ret = sysfs_create_group(dev->kobj_perf, perf->attr_group);
>>>> +               if (ret < 0)
>>>> +                       return ret;
>>>> +       }
>>>>
>>>>         return 0;
>>>>  }
>>>> @@ -778,6 +863,29 @@ static void find_system_memory(const struct dmi_header *dm,
>>>>                 }
>>>>         }
>>>>  }
>>>> +
>>>> +/*
>>>> + * Performance counters information is not part of CRAT but we would like to
>>>> + * put them in the sysfs under topology directory for Thunk to get the data.
>>>> + * This function is called before updating the sysfs.
>>>> + */
>>>> +static int kfd_add_perf_to_topology(struct kfd_topology_device *kdev)
>>>> +{
>>>> +       struct kfd_perf_properties *props;
>>>> +
>>>> +       if (amd_iommu_pc_supported()) {
>>>> +               props = kfd_alloc_struct(props);
>>>> +               if (!props)
>>>> +                       return -ENOMEM;
>>>> +               strcpy(props->block_name, "iommu");
>>>> +               props->max_concurrent = amd_iommu_pc_get_max_banks(0) *
>>>> +                       amd_iommu_pc_get_max_counters(0); /* assume one iommu */
>>>> +               list_add_tail(&props->list, &kdev->perf_props);
>>>> +       }
>>>> +
>>>> +       return 0;
>>>> +}
>>>> +
>>>>  /* kfd_add_non_crat_information - Add information that is not currently
>>>>   *     defined in CRAT but is necessary for KFD topology
>>>>   * @dev - topology device to which addition info is added
>>>> @@ -860,6 +968,10 @@ int kfd_topology_init(void)
>>>>                 }
>>>>         }
>>>>
>>>> +       kdev = list_first_entry(&temp_topology_device_list,
>>>> +                               struct kfd_topology_device, list);
>>>> +       kfd_add_perf_to_topology(kdev);
>>>> +
>>>>         down_write(&topology_lock);
>>>>         kfd_topology_update_device_list(&temp_topology_device_list,
>>>>                                         &topology_device_list);
>>>> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_topology.h b/drivers/gpu/drm/amd/amdkfd/kfd_topology.h
>>>> index 55de56f..b9f3142 100644
>>>> --- a/drivers/gpu/drm/amd/amdkfd/kfd_topology.h
>>>> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_topology.h
>>>> @@ -134,6 +134,13 @@ struct kfd_iolink_properties {
>>>>         struct attribute        attr;
>>>>  };
>>>>
>>>> +struct kfd_perf_properties {
>>>> +       struct list_head        list;
>>>> +       char                    block_name[16];
>>>> +       uint32_t                max_concurrent;
>>>> +       struct attribute_group  *attr_group;
>>>> +};
>>>> +
>>>>  struct kfd_topology_device {
>>>>         struct list_head                list;
>>>>         uint32_t                        gpu_id;
>>>> @@ -144,11 +151,13 @@ struct kfd_topology_device {
>>>>         struct list_head                cache_props;
>>>>         uint32_t                        io_link_count;
>>>>         struct list_head                io_link_props;
>>>> +       struct list_head                perf_props;
>>>>         struct kfd_dev                  *gpu;
>>>>         struct kobject                  *kobj_node;
>>>>         struct kobject                  *kobj_mem;
>>>>         struct kobject                  *kobj_cache;
>>>>         struct kobject                  *kobj_iolink;
>>>> +       struct kobject                  *kobj_perf;
>>>>         struct attribute                attr_gpuid;
>>>>         struct attribute                attr_name;
>>>>         struct attribute                attr_props;
>>>> @@ -173,4 +182,8 @@ struct kfd_topology_device *kfd_create_topology_device(
>>>>                 struct list_head *device_list);
>>>>  void kfd_release_topology_device_list(struct list_head *device_list);
>>>>
>>>> +extern bool amd_iommu_pc_supported(void);
>>>> +extern u8 amd_iommu_pc_get_max_banks(u16 devid);
>>>> +extern u8 amd_iommu_pc_get_max_counters(u16 devid);
>>>> +
>>>>  #endif /* __KFD_TOPOLOGY_H__ */
>>>> --
>>>> 2.7.4
>>>>
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