Merge pull request #605 from bgoglin/backend-info

Cleanup Backend info attribute:
All backends add a Backend=foo info attr in the root object if they added some objects to the topology.
Once and only once per backend for backends that have multiple phases.
No Backend info attr in OS devices anymore.

Author: bgoglin

NEWS

@@ -32,6 +32,8 @@ Version 3.0.0
     in PCI object attributes.
   + "Block" OS devices are now "Storage" (for actual Block devices)
     or "Memory" (for Linux DAX and CXL devices, etc).
+  + The "Backend" info attribute of OS devices is now in the topology
+    root object together with other backends.
 * Tools
   + lstopo has a new --osf option to tune the displaying of object
     attributes and units.

doc/hwloc.doxy

@@ -2046,11 +2046,11 @@ placed.
 Unless specified, these info attributes are attached to the root object (Machine).
 
 <dl>
-<dt>Backend (topology root, or specific object added by that backend)</dt>
-<dd>The name of the hwloc backend/component that filled the topology.
+<dt>Backend (topology root object)</dt>
+<dd>The name of a hwloc backend/component that added objects in the topology.
 If several components were combined, multiple Backend keys may exist,
-with different values, for instance <tt>x86</tt> and <tt>Linux</tt> in the root
-object and <tt>CUDA</tt> in CUDA OS device objects.
+with different values, for instance <tt>x86</tt>, <tt>Linux</tt> and
+<tt>CUDA</tt>.
 </dd>
 <dt>SyntheticDescription</dt>
 <dd>The description string that was given to hwloc to build this

hwloc/topology-cuda.c

@@ -73,6 +73,7 @@ hwloc_cuda_discover(struct hwloc_backend *backend, struct hwloc_disc_status *dst
   struct hwloc_topology *topology = backend->topology;
   enum hwloc_type_filter_e filter;
   cudaError_t cures;
+  unsigned added = 0;
   int nb, i;
 
   assert(dstatus->phase == HWLOC_DISC_PHASE_IO);
@@ -105,7 +106,6 @@ hwloc_cuda_discover(struct hwloc_backend *backend, struct hwloc_disc_status *dst
     cuda_device->attr->osdev.type = HWLOC_OBJ_OSDEV_COPROC;
 
     cuda_device->subtype = strdup("CUDA");
-    hwloc_obj_add_info(cuda_device, "Backend", "CUDA");
     hwloc_obj_add_info(cuda_device, "GPUVendor", "NVIDIA Corporation");
 
     cures = cudaGetDeviceProperties(&prop, i);
@@ -138,8 +138,11 @@ hwloc_cuda_discover(struct hwloc_backend *backend, struct hwloc_disc_status *dst
       parent = hwloc_get_root_obj(topology);
 
     hwloc_insert_object_by_parent(topology, parent, cuda_device);
+    added++;
   }
 
+  if (added > 0)
+    hwloc_obj_add_info(hwloc_get_root_obj(topology), "Backend", "CUDA");
   return 0;
 }
 

hwloc/topology-freebsd.c

@@ -36,6 +36,10 @@
 #include "private/private.h"
 #include "private/debug.h"
 
+struct hwloc_freebsd_backend_data_s {
+  int need_global_infos;
+};
+
 #if defined(HAVE_SYS_CPUSET_H) && defined(HAVE_CPUSET_SETAFFINITY)
 static void
 hwloc_freebsd_bsd2hwloc(hwloc_bitmap_t hwloc_cpuset, const cpuset_t *cset)
@@ -525,6 +529,7 @@ hwloc_look_freebsd(struct hwloc_backend *backend, struct hwloc_disc_status *dsta
    * we may still force use this backend when debugging with !thissystem.
    */
   struct hwloc_topology *topology = backend->topology;
+  struct hwloc_freebsd_backend_data_s *data = HWLOC_BACKEND_PRIVATE_DATA(backend);
 
   if (dstatus->phase == HWLOC_DISC_PHASE_CPU) {
     if (!topology->levels[0][0]->cpuset) {
@@ -545,8 +550,12 @@ hwloc_look_freebsd(struct hwloc_backend *backend, struct hwloc_disc_status *dsta
       memsize = hwloc_fallback_memsize();
       if (memsize > 0)
         topology->machine_memory.local_memory = memsize;
-      hwloc_obj_add_info(topology->levels[0][0], "Backend", "FreeBSD");
-      hwloc_add_uname_info(topology, NULL);
+  }
+
+  if (data->need_global_infos) {
+    hwloc_obj_add_info(topology->levels[0][0], "Backend", "FreeBSD");
+    hwloc_add_uname_info(topology, NULL);
+    data->need_global_infos = 0;
   }
   return 0;
 }
@@ -595,9 +604,15 @@ hwloc_freebsd_component_instantiate(struct hwloc_topology *topology,
 				    const void *_data3 __hwloc_attribute_unused)
 {
   struct hwloc_backend *backend;
-  backend = hwloc_backend_alloc(topology, component, 0);
+  struct hwloc_freebsd_backend_data_s *data;
+
+  backend = hwloc_backend_alloc(topology, component, sizeof(struct hwloc_freebsd_backend_data_s));
   if (!backend)
     return NULL;
+
+  data = HWLOC_BACKEND_PRIVATE_DATA(backend);
+  data->need_global_infos = 1;
+
   backend->discover = hwloc_look_freebsd;
   return backend;
 }

hwloc/topology-gl.c

@@ -32,7 +32,7 @@ hwloc_gl_discover(struct hwloc_backend *backend, struct hwloc_disc_status *dstat
 
   struct hwloc_topology *topology = backend->topology;
   enum hwloc_type_filter_e filter;
-  unsigned i;
+  unsigned i, added = 0;
   int err;
 
   assert(dstatus->phase == HWLOC_DISC_PHASE_IO);
@@ -123,7 +123,6 @@ hwloc_gl_discover(struct hwloc_backend *backend, struct hwloc_disc_status *dstat
       osdev->name = strdup(name);
       osdev->subtype = strdup("Display");
       osdev->attr->osdev.type = HWLOC_OBJ_OSDEV_GPU;
-      hwloc_obj_add_info(osdev, "Backend", "GL");
       hwloc_obj_add_info(osdev, "GPUVendor", "NVIDIA Corporation");
       if (productname)
 	hwloc_obj_add_info(osdev, "GPUModel", productname);
@@ -133,6 +132,7 @@ hwloc_gl_discover(struct hwloc_backend *backend, struct hwloc_disc_status *dstat
 	parent = hwloc_get_root_obj(topology);
 
       hwloc_insert_object_by_parent(topology, parent, osdev);
+      added++;
 
       hwloc_debug("GL device %s (product %s) on PCI %04x:%02x:%02x.%01x\n",
 		  name, productname,
@@ -141,6 +141,8 @@ hwloc_gl_discover(struct hwloc_backend *backend, struct hwloc_disc_status *dstat
     XCloseDisplay(display);
   }
 
+  if (added)
+    hwloc_obj_add_info(hwloc_get_root_obj(topology), "Backend", "GL");
   return 0;
 }
 

hwloc/topology-hardwired.c

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2015-2020 Inria.  All rights reserved.
+ * Copyright © 2015-2023 Inria.  All rights reserved.
  * See COPYING in top-level directory.
  */
 
@@ -73,6 +73,7 @@ int hwloc_look_hardwired_fujitsu_k(struct hwloc_topology *topology)
   topology->support.discovery->pu = 1;
   hwloc_setup_pu_level(topology, 8);
 
+  hwloc_obj_add_info(topology->levels[0][0], "Backend", "hardwired:K-computer");
   return 0;
 }
 
@@ -142,6 +143,7 @@ int hwloc_look_hardwired_fujitsu_fx10(struct hwloc_topology *topology)
   topology->support.discovery->pu = 1;
   hwloc_setup_pu_level(topology, 16);
 
+  hwloc_obj_add_info(topology->levels[0][0], "Backend", "hardwired:FX10");
   return 0;
 }
 
@@ -221,5 +223,6 @@ int hwloc_look_hardwired_fujitsu_fx100(struct hwloc_topology *topology)
   topology->support.discovery->pu = 1;
   hwloc_setup_pu_level(topology, 34);
 
+  hwloc_obj_add_info(topology->levels[0][0], "Backend", "hardwired:FX100");
   return 0;
 }

hwloc/topology-levelzero.c

@@ -601,7 +601,7 @@ hwloc_levelzero_discover(struct hwloc_backend *backend, struct hwloc_disc_status
   enum hwloc_type_filter_e filter;
   ze_result_t res;
   ze_driver_handle_t *drh;
-  uint32_t nbdrivers, i, k, zeidx;
+  uint32_t nbdrivers, i, k, zeidx, added = 0;
   struct hwloc_osdev_array oarray;
   struct hwloc_levelzero_ports hports;
   int sysman_maybe_missing = 0; /* 1 if ZES_ENABLE_SYSMAN=1 was NOT set early, 2 if ZES_ENABLE_SYSMAN=0 */
@@ -709,7 +709,6 @@ hwloc_levelzero_discover(struct hwloc_backend *backend, struct hwloc_disc_status
       osdev->depth = HWLOC_TYPE_DEPTH_UNKNOWN;
       osdev->attr->osdev.type = HWLOC_OBJ_OSDEV_COPROC;
       osdev->subtype = strdup("LevelZero");
-      hwloc_obj_add_info(osdev, "Backend", "LevelZero");
 
       snprintf(buffer, sizeof(buffer), "%u", i);
       hwloc_obj_add_info(osdev, "LevelZeroDriverIndex", buffer);
@@ -738,7 +737,6 @@ hwloc_levelzero_discover(struct hwloc_backend *backend, struct hwloc_disc_status
             subosdevs[k]->depth = HWLOC_TYPE_DEPTH_UNKNOWN;
             subosdevs[k]->attr->osdev.type = HWLOC_OBJ_OSDEV_COPROC;
             subosdevs[k]->subtype = strdup("LevelZero");
-            hwloc_obj_add_info(subosdevs[k], "Backend", "LevelZero");
             snprintf(tmp, sizeof(tmp), "%u", k);
             hwloc_obj_add_info(subosdevs[k], "LevelZeroSubdeviceID", tmp);
 
@@ -805,11 +803,13 @@ hwloc_levelzero_discover(struct hwloc_backend *backend, struct hwloc_disc_status
        */
       hwloc_insert_object_by_parent(topology, parent, osdev);
       hwloc__levelzero_osdev_array_add(&oarray, osdev);
+      added++;
       if (nr_subdevices) {
         for(k=0; k<nr_subdevices; k++)
           if (subosdevs[k]) {
             hwloc_insert_object_by_parent(topology, osdev, subosdevs[k]);
             hwloc__levelzero_osdev_array_add(&oarray, subosdevs[k]);
+            added++;
           }
         free(subosdevs);
         free(subh);
@@ -826,6 +826,9 @@ hwloc_levelzero_discover(struct hwloc_backend *backend, struct hwloc_disc_status
   hwloc__levelzero_osdev_array_free(&oarray);
 
   free(drh);
+
+  if (added)
+    hwloc_obj_add_info(hwloc_get_root_obj(topology), "Backend", "LevelZero");
   return 0;
 }
 

hwloc/topology-linux.c

@@ -63,6 +63,7 @@ struct hwloc_linux_backend_data_s {
   struct utsname utsname; /* fields contain \0 when unknown */
   int fallback_nbprocessors; /* only used in hwloc_linux_fallback_pu_level(), maybe be <= 0 (error) earlier */
   unsigned pagesize;
+  int need_global_infos;
 };
 
 
@@ -5768,16 +5769,6 @@ hwloc_linuxfs_look_cpu(struct hwloc_backend *backend, struct hwloc_disc_status *
 
   hwloc_alloc_root_sets(topology->levels[0][0]);
 
-  /*********************************
-   * Platform information for later
-   */
-  hwloc_gather_system_info(topology, data);
-
-  /**********************************
-   * Detect things in /proc/cmdline
-   */
-  hwloc_linuxfs_check_kernel_cmdline(data);
-
   /**********************
    * /proc/cpuinfo
    */
@@ -5862,22 +5853,11 @@ hwloc_linuxfs_look_cpu(struct hwloc_backend *backend, struct hwloc_disc_status *
   } else
     nbnodes = 0;
 
-  /**********************
-   * Misc
-   */
-
-  /* Gather DMI info */
-  hwloc__get_dmi_id_info(data, topology->levels[0][0]);
-
-  hwloc_obj_add_info(topology->levels[0][0], "Backend", "Linux");
   if (cpuset_name) {
     hwloc_obj_add_info(topology->levels[0][0], "LinuxCgroup", cpuset_name);
     free(cpuset_name);
   }
 
-  /* data->utsname was filled with real uname or \0, we can safely pass it */
-  hwloc_add_uname_info(topology, &data->utsname);
-
   hwloc_linux_free_cpuinfo(Lprocs, numprocs, global_infos, global_infos_count);
   return 0;
 }
@@ -7292,14 +7272,20 @@ hwloc_look_linuxfs(struct hwloc_backend *backend, struct hwloc_disc_status *dsta
    * or not (modified fsroot path).
    */
 
+  struct hwloc_linux_backend_data_s *data = HWLOC_BACKEND_PRIVATE_DATA(backend);
   struct hwloc_topology *topology = backend->topology;
 #ifdef HWLOC_HAVE_LINUXIO
   enum hwloc_type_filter_e pfilter, bfilter, ofilter, mfilter;
 #endif /* HWLOC_HAVE_LINUXIO */
 
+  if (data->need_global_infos) {
+    hwloc_gather_system_info(topology, data);
+    hwloc_linuxfs_check_kernel_cmdline(data);
+  }
+
   if (dstatus->phase == HWLOC_DISC_PHASE_CPU) {
     hwloc_linuxfs_look_cpu(backend, dstatus);
-    return 0;
+    goto out;
   }
 
 #ifdef HWLOC_HAVE_LINUXIO
@@ -7353,6 +7339,14 @@ hwloc_look_linuxfs(struct hwloc_backend *backend, struct hwloc_disc_status *dsta
   }
 #endif /* HWLOC_HAVE_LINUXIO */
 
+ out:
+  if (data->need_global_infos) {
+    hwloc__get_dmi_id_info(data, topology->levels[0][0]);
+    hwloc_obj_add_info(topology->levels[0][0], "Backend", "Linux");
+    /* data->utsname was filled with real uname or \0, we can safely pass it */
+    hwloc_add_uname_info(topology, &data->utsname);
+    data->need_global_infos = 0;
+  }
   return 0;
 }
 
@@ -7405,6 +7399,7 @@ hwloc_linux_component_instantiate(struct hwloc_topology *topology,
   data->is_knl = 0;
   data->is_amd_with_CU = 0;
   data->is_fake_numa_uniform = 0;
+  data->need_global_infos = 1;
   data->is_real_fsroot = 1;
   data->root_path = NULL;
   fsroot_path = getenv("HWLOC_FSROOT");

hwloc/topology-noos.c

@@ -35,6 +35,7 @@ hwloc_look_noos(struct hwloc_backend *backend, struct hwloc_disc_status *dstatus
       nbprocs = 1;
     hwloc_alloc_root_sets(topology->levels[0][0]);
     hwloc_setup_pu_level(topology, nbprocs);
+    hwloc_obj_add_info(topology->levels[0][0], "Backend", "noOS");
   }
 
   memsize = hwloc_fallback_memsize();

hwloc/topology-nvml.c

@@ -159,7 +159,7 @@ hwloc_nvml_discover(struct hwloc_backend *backend, struct hwloc_disc_status *dst
   struct hwloc_topology *topology = backend->topology;
   enum hwloc_type_filter_e filter;
   nvmlReturn_t ret;
-  unsigned nb, i;
+  unsigned nb, i, added = 0;
 #ifdef NVML_NVLINK_MAX_LINKS
   unsigned nbobjs, j;
   hwloc_obj_t *objs;
@@ -224,7 +224,6 @@ hwloc_nvml_discover(struct hwloc_backend *backend, struct hwloc_disc_status *dst
     osdev->depth = HWLOC_TYPE_DEPTH_UNKNOWN;
     osdev->attr->osdev.type = HWLOC_OBJ_OSDEV_GPU;
 
-    hwloc_obj_add_info(osdev, "Backend", "NVML");
     hwloc_obj_add_info(osdev, "GPUVendor", "NVIDIA Corporation");
 
     buffer[0] = '\0';
@@ -272,6 +271,7 @@ hwloc_nvml_discover(struct hwloc_backend *backend, struct hwloc_disc_status *dst
 #ifdef NVML_NVLINK_MAX_LINKS
     objs[i] = osdev;
 #endif
+    added++;
   }
 
 #ifdef NVML_NVLINK_MAX_LINKS
@@ -397,6 +397,9 @@ hwloc_nvml_discover(struct hwloc_backend *backend, struct hwloc_disc_status *dst
 #endif /* NVML_NVLINK_MAX_LINKS */
 
   nvmlShutdown();
+
+  if (added)
+    hwloc_obj_add_info(hwloc_get_root_obj(topology), "Backend", "NVML");
   return 0;
 }