Author: cem
Date: Tue Aug 22 00:10:15 2017
New Revision: 322776
URL: https://svnweb.freebsd.org/changeset/base/322776

Log:
  subr_smp: Clean up topology analysis, add additional layers
  
  Rather than repeatedly nesting loops, separate concerns with a single loop
  per call stack level.  Use a table to drive the recursive routine.  Handle
  missing topology layers more gracefully (infer a single unit).
  
  Analyze some additional optional layers which may be present on e.g. AMD Zen
  systems (groups, aka dies, per package; and cachegroups, aka CCXes, per
  group).
  
  Display that additional information in the boot-time topology information,
  when it is relevent (non-one).
  
  Reviewed by:  markj@, mjoras@ (earlier version)
  Sponsored by: Dell EMC Isilon
  Differential Revision:        https://reviews.freebsd.org/D12019

Modified:
  head/sys/kern/subr_smp.c
  head/sys/sys/smp.h
  head/sys/x86/x86/mp_x86.c

Modified: head/sys/kern/subr_smp.c
==============================================================================
--- head/sys/kern/subr_smp.c    Mon Aug 21 22:26:49 2017        (r322775)
+++ head/sys/kern/subr_smp.c    Tue Aug 22 00:10:15 2017        (r322776)
@@ -993,7 +993,7 @@ topo_next_node(struct topo_node *top, struct topo_node
        if ((next = TAILQ_NEXT(node, siblings)) != NULL)
                return (next);
 
-       while ((node = node->parent) != top)
+       while (node != top && (node = node->parent) != top)
                if ((next = TAILQ_NEXT(node, siblings)) != NULL)
                        return (next);
 
@@ -1012,7 +1012,7 @@ topo_next_nonchild_node(struct topo_node *top, struct 
        if ((next = TAILQ_NEXT(node, siblings)) != NULL)
                return (next);
 
-       while ((node = node->parent) != top)
+       while (node != top && (node = node->parent) != top)
                if ((next = TAILQ_NEXT(node, siblings)) != NULL)
                        return (next);
 
@@ -1044,105 +1044,99 @@ topo_set_pu_id(struct topo_node *node, cpuid_t id)
        }
 }
 
-/*
- * Check if the topology is uniform, that is, each package has the same number
- * of cores in it and each core has the same number of threads (logical
- * processors) in it.  If so, calculate the number of package, the number of
- * cores per package and the number of logical processors per core.
- * 'all' parameter tells whether to include administratively disabled logical
- * processors into the analysis.
- */
-int
-topo_analyze(struct topo_node *topo_root, int all,
-    int *pkg_count, int *cores_per_pkg, int *thrs_per_core)
+static struct topology_spec {
+       topo_node_type  type;
+       bool            match_subtype;
+       uintptr_t       subtype;
+} topology_level_table[TOPO_LEVEL_COUNT] = {
+       [TOPO_LEVEL_PKG] = { .type = TOPO_TYPE_PKG, },
+       [TOPO_LEVEL_GROUP] = { .type = TOPO_TYPE_GROUP, },
+       [TOPO_LEVEL_CACHEGROUP] = {
+               .type = TOPO_TYPE_CACHE,
+               .match_subtype = true,
+               .subtype = CG_SHARE_L3,
+       },
+       [TOPO_LEVEL_CORE] = { .type = TOPO_TYPE_CORE, },
+       [TOPO_LEVEL_THREAD] = { .type = TOPO_TYPE_PU, },
+};
+
+static bool
+topo_analyze_table(struct topo_node *root, int all, enum topo_level level,
+    struct topo_analysis *results)
 {
-       struct topo_node *pkg_node;
-       struct topo_node *core_node;
-       struct topo_node *pu_node;
-       int thrs_per_pkg;
-       int cpp_counter;
-       int tpc_counter;
-       int tpp_counter;
+       struct topology_spec *spec;
+       struct topo_node *node;
+       int count;
 
-       *pkg_count = 0;
-       *cores_per_pkg = -1;
-       *thrs_per_core = -1;
-       thrs_per_pkg = -1;
-       pkg_node = topo_root;
-       while (pkg_node != NULL) {
-               if (pkg_node->type != TOPO_TYPE_PKG) {
-                       pkg_node = topo_next_node(topo_root, pkg_node);
+       if (level >= TOPO_LEVEL_COUNT)
+               return (true);
+
+       spec = &topology_level_table[level];
+       count = 0;
+       node = topo_next_node(root, root);
+
+       while (node != NULL) {
+               if (node->type != spec->type ||
+                   (spec->match_subtype && node->subtype != spec->subtype)) {
+                       node = topo_next_node(root, node);
                        continue;
                }
-               if (!all && CPU_EMPTY(&pkg_node->cpuset)) {
-                       pkg_node = topo_next_nonchild_node(topo_root, pkg_node);
+               if (!all && CPU_EMPTY(&node->cpuset)) {
+                       node = topo_next_nonchild_node(root, node);
                        continue;
                }
 
-               (*pkg_count)++;
+               count++;
 
-               cpp_counter = 0;
-               tpp_counter = 0;
-               core_node = pkg_node;
-               while (core_node != NULL) {
-                       if (core_node->type == TOPO_TYPE_CORE) {
-                               if (!all && CPU_EMPTY(&core_node->cpuset)) {
-                                       core_node =
-                                           topo_next_nonchild_node(pkg_node,
-                                               core_node);
-                                       continue;
-                               }
+               if (!topo_analyze_table(node, all, level + 1, results))
+                       return (false);
 
-                               cpp_counter++;
+               node = topo_next_nonchild_node(root, node);
+       }
 
-                               tpc_counter = 0;
-                               pu_node = core_node;
-                               while (pu_node != NULL) {
-                                       if (pu_node->type == TOPO_TYPE_PU &&
-                                           (all || 
!CPU_EMPTY(&pu_node->cpuset)))
-                                               tpc_counter++;
-                                       pu_node = topo_next_node(core_node,
-                                           pu_node);
-                               }
+       /* No explicit subgroups is essentially one subgroup. */
+       if (count == 0) {
+               count = 1;
 
-                               if (*thrs_per_core == -1)
-                                       *thrs_per_core = tpc_counter;
-                               else if (*thrs_per_core != tpc_counter)
-                                       return (0);
+               if (!topo_analyze_table(root, all, level + 1, results))
+                       return (false);
+       }
 
-                               core_node = topo_next_nonchild_node(pkg_node,
-                                   core_node);
-                       } else {
-                               /* PU node directly under PKG. */
-                               if (core_node->type == TOPO_TYPE_PU &&
-                                  (all || !CPU_EMPTY(&core_node->cpuset)))
-                                       tpp_counter++;
-                               core_node = topo_next_node(pkg_node,
-                                   core_node);
-                       }
-               }
+       if (results->entities[level] == -1)
+               results->entities[level] = count;
+       else if (results->entities[level] != count)
+               return (false);
 
-               if (*cores_per_pkg == -1)
-                       *cores_per_pkg = cpp_counter;
-               else if (*cores_per_pkg != cpp_counter)
-                       return (0);
-               if (thrs_per_pkg == -1)
-                       thrs_per_pkg = tpp_counter;
-               else if (thrs_per_pkg != tpp_counter)
-                       return (0);
+       return (true);
+}
 
-               pkg_node = topo_next_nonchild_node(topo_root, pkg_node);
-       }
+/*
+ * Check if the topology is uniform, that is, each package has the same number
+ * of cores in it and each core has the same number of threads (logical
+ * processors) in it.  If so, calculate the number of packages, the number of
+ * groups per package, the number of cachegroups per group, and the number of
+ * logical processors per cachegroup.  'all' parameter tells whether to include
+ * administratively disabled logical processors into the analysis.
+ */
+int
+topo_analyze(struct topo_node *topo_root, int all,
+    struct topo_analysis *results)
+{
 
-       KASSERT(*pkg_count > 0,
+       results->entities[TOPO_LEVEL_PKG] = -1;
+       results->entities[TOPO_LEVEL_CORE] = -1;
+       results->entities[TOPO_LEVEL_THREAD] = -1;
+       results->entities[TOPO_LEVEL_GROUP] = -1;
+       results->entities[TOPO_LEVEL_CACHEGROUP] = -1;
+
+       if (!topo_analyze_table(topo_root, all, TOPO_LEVEL_PKG, results))
+               return (0);
+
+       KASSERT(results->entities[TOPO_LEVEL_PKG] > 0,
                ("bug in topology or analysis"));
-       if (*cores_per_pkg == 0) {
-               KASSERT(*thrs_per_core == -1 && thrs_per_pkg > 0,
-                       ("bug in topology or analysis"));
-               *thrs_per_core = thrs_per_pkg;
-       }
 
        return (1);
 }
+
 #endif /* SMP */
 

Modified: head/sys/sys/smp.h
==============================================================================
--- head/sys/sys/smp.h  Mon Aug 21 22:26:49 2017        (r322775)
+++ head/sys/sys/smp.h  Tue Aug 22 00:10:15 2017        (r322776)
@@ -120,8 +120,25 @@ struct topo_node * topo_next_node(struct topo_node *to
 struct topo_node * topo_next_nonchild_node(struct topo_node *top,
     struct topo_node *node);
 void topo_set_pu_id(struct topo_node *node, cpuid_t id);
-int topo_analyze(struct topo_node *topo_root, int all, int *pkg_count,
-    int *cores_per_pkg, int *thrs_per_core);
+
+enum topo_level {
+       TOPO_LEVEL_PKG = 0,
+       /*
+        * Some systems have useful sub-package core organizations.  On these,
+        * a package has one or more subgroups.  Each subgroup contains one or
+        * more cache groups (cores that share a last level cache).
+        */
+       TOPO_LEVEL_GROUP,
+       TOPO_LEVEL_CACHEGROUP,
+       TOPO_LEVEL_CORE,
+       TOPO_LEVEL_THREAD,
+       TOPO_LEVEL_COUNT        /* Must be last */
+};
+struct topo_analysis {
+       int entities[TOPO_LEVEL_COUNT];
+};
+int topo_analyze(struct topo_node *topo_root, int all,
+    struct topo_analysis *results);
 
 #define        TOPO_FOREACH(i, root)   \
        for (i = root; i != NULL; i = topo_next_node(root, i))

Modified: head/sys/x86/x86/mp_x86.c
==============================================================================
--- head/sys/x86/x86/mp_x86.c   Mon Aug 21 22:26:49 2017        (r322775)
+++ head/sys/x86/x86/mp_x86.c   Tue Aug 22 00:10:15 2017        (r322776)
@@ -662,18 +662,23 @@ cpu_mp_announce(void)
 {
        struct topo_node *node;
        const char *hyperthread;
-       int pkg_count;
-       int cores_per_pkg;
-       int thrs_per_core;
+       struct topo_analysis topology;
 
        printf("FreeBSD/SMP: ");
-       if (topo_analyze(&topo_root, 1, &pkg_count,
-           &cores_per_pkg, &thrs_per_core)) {
-               printf("%d package(s)", pkg_count);
-               if (cores_per_pkg > 0)
-                       printf(" x %d core(s)", cores_per_pkg);
-               if (thrs_per_core > 1)
-                   printf(" x %d hardware threads", thrs_per_core);
+       if (topo_analyze(&topo_root, 1, &topology)) {
+               printf("%d package(s)", topology.entities[TOPO_LEVEL_PKG]);
+               if (topology.entities[TOPO_LEVEL_GROUP] > 1)
+                       printf(" x %d groups",
+                           topology.entities[TOPO_LEVEL_GROUP]);
+               if (topology.entities[TOPO_LEVEL_CACHEGROUP] > 1)
+                       printf(" x %d cache groups",
+                           topology.entities[TOPO_LEVEL_CACHEGROUP]);
+               if (topology.entities[TOPO_LEVEL_CORE] > 0)
+                       printf(" x %d core(s)",
+                           topology.entities[TOPO_LEVEL_CORE]);
+               if (topology.entities[TOPO_LEVEL_THREAD] > 1)
+                       printf(" x %d hardware threads",
+                           topology.entities[TOPO_LEVEL_THREAD]);
        } else {
                printf("Non-uniform topology");
        }
@@ -681,13 +686,21 @@ cpu_mp_announce(void)
 
        if (disabled_cpus) {
                printf("FreeBSD/SMP Online: ");
-               if (topo_analyze(&topo_root, 0, &pkg_count,
-                   &cores_per_pkg, &thrs_per_core)) {
-                       printf("%d package(s)", pkg_count);
-                       if (cores_per_pkg > 0)
-                               printf(" x %d core(s)", cores_per_pkg);
-                       if (thrs_per_core > 1)
-                           printf(" x %d hardware threads", thrs_per_core);
+               if (topo_analyze(&topo_root, 0, &topology)) {
+                       printf("%d package(s)",
+                           topology.entities[TOPO_LEVEL_PKG]);
+                       if (topology.entities[TOPO_LEVEL_GROUP] > 1)
+                               printf(" x %d groups",
+                                   topology.entities[TOPO_LEVEL_GROUP]);
+                       if (topology.entities[TOPO_LEVEL_CACHEGROUP] > 1)
+                               printf(" x %d cache groups",
+                                   topology.entities[TOPO_LEVEL_CACHEGROUP]);
+                       if (topology.entities[TOPO_LEVEL_CORE] > 0)
+                               printf(" x %d core(s)",
+                                   topology.entities[TOPO_LEVEL_CORE]);
+                       if (topology.entities[TOPO_LEVEL_THREAD] > 1)
+                               printf(" x %d hardware threads",
+                                   topology.entities[TOPO_LEVEL_THREAD]);
                } else {
                        printf("Non-uniform topology");
                }
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