[PATCH 3/3] drm/amdkfd: Extend KFD device topology to surface peer-to-peer links
Felix Kuehling
felix.kuehling at amd.com
Mon Jun 6 21:07:52 UTC 2022
Am 2022-06-06 um 14:08 schrieb Ramesh Errabolu:
> Extend KFD device topology to surface peer-to-peer links among
> GPU devices connected over PCIe or xGMI. Enabling HSA_AMD_P2P is
> REQUIRED to surface peer-to-peer links.
>
> Prior to this KFD did not expose to user mode any P2P links or
> indirect links that go over two or more direct hops. Old versions
> of the Thunk used to make up their own P2P and indirect links without
> the information about peer-accessibility and chipset support available
> to the kernel mode driver. In this patch we expose P2P links in a new
> sysfs directory to provide more reliable P2P link information to user
> mode.
>
> Old versions of the Thunk will continue to work as before and ignore
> the new directory. This avoids conflicts between P2P links exposed by
> KFD and P2P links created by the Thunk itself. New versions of the Thunk
> will use only the P2P links provided in the new p2p_links directory, if
> it exists, or fall back to the old code path on older KFDs that don't
> expose p2p_links.
>
> Signed-off-by: Ramesh Errabolu <Ramesh.Errabolu at amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling at amd.com>
> ---
> drivers/gpu/drm/amd/amdkfd/kfd_topology.c | 319 +++++++++++++++++++++-
> drivers/gpu/drm/amd/amdkfd/kfd_topology.h | 3 +
> 2 files changed, 320 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_topology.c b/drivers/gpu/drm/amd/amdkfd/kfd_topology.c
> index 8d50d207cf66..3e240b22ec91 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_topology.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_topology.c
> @@ -40,6 +40,7 @@
> #include "kfd_svm.h"
> #include "amdgpu_amdkfd.h"
> #include "amdgpu_ras.h"
> +#include "amdgpu.h"
>
> /* topology_device_list - Master list of all topology devices */
> static struct list_head topology_device_list;
> @@ -148,6 +149,7 @@ 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_iolink_properties *p2plink;
> struct kfd_perf_properties *perf;
>
> list_del(&dev->list);
> @@ -173,6 +175,13 @@ static void kfd_release_topology_device(struct kfd_topology_device *dev)
> kfree(iolink);
> }
>
> + while (dev->p2p_link_props.next != &dev->p2p_link_props) {
> + p2plink = container_of(dev->p2p_link_props.next,
> + struct kfd_iolink_properties, list);
> + list_del(&p2plink->list);
> + kfree(p2plink);
> + }
> +
> while (dev->perf_props.next != &dev->perf_props) {
> perf = container_of(dev->perf_props.next,
> struct kfd_perf_properties, list);
> @@ -214,6 +223,7 @@ 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->p2p_link_props);
> INIT_LIST_HEAD(&dev->perf_props);
>
> list_add_tail(&dev->list, device_list);
> @@ -465,6 +475,8 @@ static ssize_t node_show(struct kobject *kobj, struct attribute *attr,
> dev->node_props.caches_count);
> sysfs_show_32bit_prop(buffer, offs, "io_links_count",
> dev->node_props.io_links_count);
> + sysfs_show_32bit_prop(buffer, offs, "p2p_links_count",
> + dev->node_props.p2p_links_count);
> sysfs_show_32bit_prop(buffer, offs, "cpu_core_id_base",
> dev->node_props.cpu_core_id_base);
> sysfs_show_32bit_prop(buffer, offs, "simd_id_base",
> @@ -568,6 +580,7 @@ static void kfd_remove_sysfs_file(struct kobject *kobj, struct attribute *attr)
>
> static void kfd_remove_sysfs_node_entry(struct kfd_topology_device *dev)
> {
> + struct kfd_iolink_properties *p2plink;
> struct kfd_iolink_properties *iolink;
> struct kfd_cache_properties *cache;
> struct kfd_mem_properties *mem;
> @@ -585,6 +598,18 @@ static void kfd_remove_sysfs_node_entry(struct kfd_topology_device *dev)
> dev->kobj_iolink = NULL;
> }
>
> + if (dev->kobj_p2plink) {
> + list_for_each_entry(p2plink, &dev->p2p_link_props, list)
> + if (p2plink->kobj) {
> + kfd_remove_sysfs_file(p2plink->kobj,
> + &p2plink->attr);
> + p2plink->kobj = NULL;
> + }
> + kobject_del(dev->kobj_p2plink);
> + kobject_put(dev->kobj_p2plink);
> + dev->kobj_p2plink = NULL;
> + }
> +
> if (dev->kobj_cache) {
> list_for_each_entry(cache, &dev->cache_props, list)
> if (cache->kobj) {
> @@ -631,6 +656,7 @@ static void kfd_remove_sysfs_node_entry(struct kfd_topology_device *dev)
> static int kfd_build_sysfs_node_entry(struct kfd_topology_device *dev,
> uint32_t id)
> {
> + struct kfd_iolink_properties *p2plink;
> struct kfd_iolink_properties *iolink;
> struct kfd_cache_properties *cache;
> struct kfd_mem_properties *mem;
> @@ -668,6 +694,10 @@ static int kfd_build_sysfs_node_entry(struct kfd_topology_device *dev,
> if (!dev->kobj_iolink)
> return -ENOMEM;
>
> + dev->kobj_p2plink = kobject_create_and_add("p2p_links", dev->kobj_node);
> + if (!dev->kobj_p2plink)
> + return -ENOMEM;
> +
> dev->kobj_perf = kobject_create_and_add("perf", dev->kobj_node);
> if (!dev->kobj_perf)
> return -ENOMEM;
> @@ -757,6 +787,27 @@ static int kfd_build_sysfs_node_entry(struct kfd_topology_device *dev,
> i++;
> }
>
> + i = 0;
> + list_for_each_entry(p2plink, &dev->p2p_link_props, list) {
> + p2plink->kobj = kzalloc(sizeof(struct kobject), GFP_KERNEL);
> + if (!p2plink->kobj)
> + return -ENOMEM;
> + ret = kobject_init_and_add(p2plink->kobj, &iolink_type,
> + dev->kobj_p2plink, "%d", i);
> + if (ret < 0) {
> + kobject_put(p2plink->kobj);
> + return ret;
> + }
> +
> + p2plink->attr.name = "properties";
> + p2plink->attr.mode = KFD_SYSFS_FILE_MODE;
> + sysfs_attr_init(&iolink->attr);
> + ret = sysfs_create_file(p2plink->kobj, &p2plink->attr);
> + if (ret < 0)
> + return ret;
> + i++;
> + }
> +
> /* All hardware blocks have the same number of attributes. */
> num_attrs = ARRAY_SIZE(perf_attr_iommu);
> list_for_each_entry(perf, &dev->perf_props, list) {
> @@ -1145,6 +1196,7 @@ static struct kfd_topology_device *kfd_assign_gpu(struct kfd_dev *gpu)
> struct kfd_mem_properties *mem;
> struct kfd_cache_properties *cache;
> struct kfd_iolink_properties *iolink;
> + struct kfd_iolink_properties *p2plink;
>
> down_write(&topology_lock);
> list_for_each_entry(dev, &topology_device_list, list) {
> @@ -1165,6 +1217,8 @@ static struct kfd_topology_device *kfd_assign_gpu(struct kfd_dev *gpu)
> cache->gpu = dev->gpu;
> list_for_each_entry(iolink, &dev->io_link_props, list)
> iolink->gpu = dev->gpu;
> + list_for_each_entry(p2plink, &dev->p2p_link_props, list)
> + p2plink->gpu = dev->gpu;
> break;
> }
> }
> @@ -1287,6 +1341,250 @@ static void kfd_fill_iolink_non_crat_info(struct kfd_topology_device *dev)
> kfd_set_iolink_non_coherent(peer_dev, link, inbound_link);
> }
> }
> +
> + /* Create indirect links so apply flags setting to all */
> + list_for_each_entry(link, &dev->p2p_link_props, list) {
> + link->flags = CRAT_IOLINK_FLAGS_ENABLED;
> + kfd_set_iolink_no_atomics(dev, NULL, link);
> + peer_dev = kfd_topology_device_by_proximity_domain(
> + link->node_to);
> +
> + if (!peer_dev)
> + continue;
> +
> + list_for_each_entry(inbound_link, &peer_dev->p2p_link_props,
> + list) {
> + if (inbound_link->node_to != link->node_from)
> + continue;
> +
> + inbound_link->flags = CRAT_IOLINK_FLAGS_ENABLED;
> + kfd_set_iolink_no_atomics(peer_dev, dev, inbound_link);
> + kfd_set_iolink_non_coherent(peer_dev, link, inbound_link);
> + }
> + }
> +}
> +
> +static int kfd_build_p2p_node_entry(struct kfd_topology_device *dev,
> + struct kfd_iolink_properties *p2plink)
> +{
> + int ret;
> +
> + p2plink->kobj = kzalloc(sizeof(struct kobject), GFP_KERNEL);
> + if (!p2plink->kobj)
> + return -ENOMEM;
> +
> + ret = kobject_init_and_add(p2plink->kobj, &iolink_type,
> + dev->kobj_p2plink, "%d", dev->node_props.p2p_links_count - 1);
> + if (ret < 0) {
> + kobject_put(p2plink->kobj);
> + return ret;
> + }
> +
> + p2plink->attr.name = "properties";
> + p2plink->attr.mode = KFD_SYSFS_FILE_MODE;
> + sysfs_attr_init(&p2plink->attr);
> + ret = sysfs_create_file(p2plink->kobj, &p2plink->attr);
> + if (ret < 0)
> + return ret;
> +
> + return 0;
> +}
> +
> +static int kfd_create_indirect_link_prop(struct kfd_topology_device *kdev, int gpu_node)
> +{
> + struct kfd_iolink_properties *props = NULL, *props2 = NULL;
> + struct kfd_iolink_properties *gpu_link, *cpu_link;
> + struct kfd_topology_device *cpu_dev;
> + int ret = 0;
> + int i, num_cpu;
> +
> + num_cpu = 0;
> + list_for_each_entry(cpu_dev, &topology_device_list, list) {
> + if (cpu_dev->gpu)
> + break;
> + num_cpu++;
> + }
> +
> + gpu_link = list_first_entry(&kdev->io_link_props,
> + struct kfd_iolink_properties, list);
> + if (!gpu_link)
> + return -ENOMEM;
> +
> + for (i = 0; i < num_cpu; i++) {
> + /* CPU <--> GPU */
> + if (gpu_link->node_to == i)
> + continue;
> +
> + /* find CPU <--> CPU links */
> + cpu_dev = kfd_topology_device_by_proximity_domain(i);
> + if (cpu_dev) {
> + list_for_each_entry(cpu_link,
> + &cpu_dev->io_link_props, list) {
> + if (cpu_link->node_to == gpu_link->node_to)
> + break;
> + }
> + }
> +
> + if (cpu_link->node_to != gpu_link->node_to)
> + return -ENOMEM;
> +
> + /* CPU <--> CPU <--> GPU, GPU node*/
> + props = kfd_alloc_struct(props);
> + if (!props)
> + return -ENOMEM;
> +
> + memcpy(props, gpu_link, sizeof(struct kfd_iolink_properties));
> + props->weight = gpu_link->weight + cpu_link->weight;
> + props->min_latency = gpu_link->min_latency + cpu_link->min_latency;
> + props->max_latency = gpu_link->max_latency + cpu_link->max_latency;
> + props->min_bandwidth = min(gpu_link->min_bandwidth, cpu_link->min_bandwidth);
> + props->max_bandwidth = min(gpu_link->max_bandwidth, cpu_link->max_bandwidth);
> +
> + props->node_from = gpu_node;
> + props->node_to = i;
> + kdev->node_props.p2p_links_count++;
> + list_add_tail(&props->list, &kdev->p2p_link_props);
> + ret = kfd_build_p2p_node_entry(kdev, props);
> + if (ret < 0)
> + return ret;
> +
> + /* for small Bar, no CPU --> GPU in-direct links */
> + if (kfd_dev_is_large_bar(kdev->gpu)) {
> + /* CPU <--> CPU <--> GPU, CPU node*/
> + props2 = kfd_alloc_struct(props2);
> + if (!props2)
> + return -ENOMEM;
> +
> + memcpy(props2, props, sizeof(struct kfd_iolink_properties));
> + props2->node_from = i;
> + props2->node_to = gpu_node;
> + props2->kobj = NULL;
> + cpu_dev->node_props.p2p_links_count++;
> + list_add_tail(&props2->list, &cpu_dev->p2p_link_props);
> + ret = kfd_build_p2p_node_entry(cpu_dev, props2);
> + if (ret < 0)
> + return ret;
> + }
> + }
> + return ret;
> +}
> +
> +#if defined(CONFIG_HSA_AMD_P2P)
> +static int kfd_add_peer_prop(struct kfd_topology_device *kdev,
> + struct kfd_topology_device *peer, int from, int to)
> +{
> + struct kfd_iolink_properties *props = NULL;
> + struct kfd_iolink_properties *iolink1, *iolink2, *iolink3;
> + struct kfd_topology_device *cpu_dev;
> + int ret = 0;
> +
> + if (!amdgpu_device_is_peer_accessible(
> + kdev->gpu->adev,
> + peer->gpu->adev))
> + return ret;
> +
> + iolink1 = list_first_entry(&kdev->io_link_props,
> + struct kfd_iolink_properties, list);
> + if (!iolink1)
> + return -ENOMEM;
> +
> + iolink2 = list_first_entry(&peer->io_link_props,
> + struct kfd_iolink_properties, list);
> + if (!iolink2)
> + return -ENOMEM;
> +
> + props = kfd_alloc_struct(props);
> + if (!props)
> + return -ENOMEM;
> +
> + memcpy(props, iolink1, sizeof(struct kfd_iolink_properties));
> +
> + props->weight = iolink1->weight + iolink2->weight;
> + props->min_latency = iolink1->min_latency + iolink2->min_latency;
> + props->max_latency = iolink1->max_latency + iolink2->max_latency;
> + props->min_bandwidth = min(iolink1->min_bandwidth, iolink2->min_bandwidth);
> + props->max_bandwidth = min(iolink2->max_bandwidth, iolink2->max_bandwidth);
> +
> + if (iolink1->node_to != iolink2->node_to) {
> + /* CPU->CPU link*/
> + cpu_dev = kfd_topology_device_by_proximity_domain(iolink1->node_to);
> + if (cpu_dev) {
> + list_for_each_entry(iolink3, &cpu_dev->io_link_props, list)
> + if (iolink3->node_to == iolink2->node_to)
> + break;
> +
> + props->weight += iolink3->weight;
> + props->min_latency += iolink3->min_latency;
> + props->max_latency += iolink3->max_latency;
> + props->min_bandwidth = min(props->min_bandwidth,
> + iolink3->min_bandwidth);
> + props->max_bandwidth = min(props->max_bandwidth,
> + iolink3->max_bandwidth);
> + } else {
> + WARN(1, "CPU node not found");
> + }
> + }
> +
> + props->node_from = from;
> + props->node_to = to;
> + peer->node_props.p2p_links_count++;
> + list_add_tail(&props->list, &peer->p2p_link_props);
> + ret = kfd_build_p2p_node_entry(peer, props);
> +
> + return ret;
> +}
> +#endif
> +
> +static int kfd_dev_create_p2p_links(void)
> +{
> + struct kfd_topology_device *dev;
> + struct kfd_topology_device *new_dev;
> + uint32_t i, k;
> + int ret = 0;
> +
> + k = 0;
> + list_for_each_entry(dev, &topology_device_list, list)
> + k++;
> + if (k < 2)
> + return 0;
> +
> + new_dev = list_last_entry(&topology_device_list, struct kfd_topology_device, list);
> + if (WARN_ON(!new_dev->gpu))
> + return 0;
> +
> + k--;
> + i = 0;
> +
> + /* create in-direct links */
> + ret = kfd_create_indirect_link_prop(new_dev, k);
> + if (ret < 0)
> + goto out;
> +
> + /* create p2p links */
> +#if defined(CONFIG_HSA_AMD_P2P)
> + list_for_each_entry(dev, &topology_device_list, list) {
> + if (dev == new_dev)
> + break;
> + if (!dev->gpu || !dev->gpu->adev ||
> + (dev->gpu->hive_id &&
> + dev->gpu->hive_id == new_dev->gpu->hive_id))
> + goto next;
> +
> + /* check if node(s) is/are peer accessible in one direction or bi-direction */
> + ret = kfd_add_peer_prop(new_dev, dev, i, k);
> + if (ret < 0)
> + goto out;
> +
> + ret = kfd_add_peer_prop(dev, new_dev, k, i);
> + if (ret < 0)
> + goto out;
> +next:
> + i++;
> + }
> +#endif
> +
> +out:
> + return ret;
> }
>
> int kfd_topology_add_device(struct kfd_dev *gpu)
> @@ -1305,7 +1603,6 @@ int kfd_topology_add_device(struct kfd_dev *gpu)
> INIT_LIST_HEAD(&temp_topology_device_list);
>
> gpu_id = kfd_generate_gpu_id(gpu);
> -
> pr_debug("Adding new GPU (ID: 0x%x) to topology\n", gpu_id);
>
> /* Check to see if this gpu device exists in the topology_device_list.
> @@ -1362,6 +1659,8 @@ int kfd_topology_add_device(struct kfd_dev *gpu)
> dev->gpu_id = gpu_id;
> gpu->id = gpu_id;
>
> + kfd_dev_create_p2p_links();
> +
> /* TODO: Move the following lines to function
> * kfd_add_non_crat_information
> */
> @@ -1507,7 +1806,7 @@ int kfd_topology_add_device(struct kfd_dev *gpu)
> static void kfd_topology_update_io_links(int proximity_domain)
> {
> struct kfd_topology_device *dev;
> - struct kfd_iolink_properties *iolink, *tmp;
> + struct kfd_iolink_properties *iolink, *p2plink, *tmp;
>
> list_for_each_entry(dev, &topology_device_list, list) {
> if (dev->proximity_domain > proximity_domain)
> @@ -1529,6 +1828,22 @@ static void kfd_topology_update_io_links(int proximity_domain)
> iolink->node_to--;
> }
> }
> +
> + list_for_each_entry_safe(p2plink, tmp, &dev->p2p_link_props, list) {
> + /*
> + * If there is a p2p link to the dev being deleted
> + * then remove that p2p link also.
> + */
> + if (p2plink->node_to == proximity_domain) {
> + list_del(&p2plink->list);
> + dev->node_props.p2p_links_count--;
> + } else {
> + if (p2plink->node_from > proximity_domain)
> + p2plink->node_from--;
> + if (p2plink->node_to > proximity_domain)
> + p2plink->node_to--;
> + }
> + }
> }
> }
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_topology.h b/drivers/gpu/drm/amd/amdkfd/kfd_topology.h
> index 4f80d2ea1000..2fb5664e1041 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_topology.h
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_topology.h
> @@ -38,6 +38,7 @@ struct kfd_node_properties {
> uint32_t mem_banks_count;
> uint32_t caches_count;
> uint32_t io_links_count;
> + uint32_t p2p_links_count;
> uint32_t cpu_core_id_base;
> uint32_t simd_id_base;
> uint32_t capability;
> @@ -131,12 +132,14 @@ struct kfd_topology_device {
> struct list_head cache_props;
> uint32_t io_link_count;
> struct list_head io_link_props;
> + struct list_head p2p_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_p2plink;
> struct kobject *kobj_perf;
> struct attribute attr_gpuid;
> struct attribute attr_name;
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