MINOR: cpu-topo: create an array of the clusters

The goal here is to keep an array of the known CPU clusters, because
we'll use that often to decide of the performance of a cluster and
its relevance compared to other ones. We'll store the number of CPUs
in it, the total capacity etc. For the capacity, we count one unit
per core, and 1/3 of it per extra SMT thread, since this is roughly
what has been measured on modern CPUs.

In order to ease debugging, they're also dumped with -dc.

diff --git a/include/haproxy/cpu_topo-t.h b/include/haproxy/cpu_topo-t.h
index b733d11d16f7bcc63c439376d3040fb861b60e48..cb6e4f0058a023985581857ccab08d5974b9a296 100644 (file)
--- a/include/haproxy/cpu_topo-t.h
+++ b/include/haproxy/cpu_topo-t.h
@@ -41,4 +41,12 @@ struct ha_cpu_topo {
        short capa;   // estimated CPU relative capacity; more is better
 };
 
+/* Description of a CPU cluster. */
+struct ha_cpu_cluster {
+       uint idx;         /* used when sorting, normally the entry index */
+       uint capa;        /* total capacity */
+       uint nb_cores;    /* total distinct cores */
+       uint nb_cpu;      /* total CPUs */
+};
+
 #endif /* _HAPROXY_CPU_TOPO_T_H */

diff --git a/src/cpu_topo.c b/src/cpu_topo.c
index 8349822227bc0bb2aaf2ca18c32581b4ead49a84..dc1d446e1ed6697f2ec16010f174d9017f8bdfc3 100644 (file)
--- a/src/cpu_topo.c
+++ b/src/cpu_topo.c
@@ -20,6 +20,7 @@
 int cpu_topo_maxcpus  = -1;  // max number of CPUs supported by OS/haproxy
 int cpu_topo_lastcpu  = -1;  // last supposed online CPU (no need to look beyond)
 struct ha_cpu_topo *ha_cpu_topo = NULL;
+struct ha_cpu_cluster *ha_cpu_clusters = NULL;
 struct cpu_map *cpu_map;
 
 /* non-zero if we're certain that taskset or similar was used to force CPUs */
@@ -219,6 +220,16 @@ void cpu_dump_topology(const struct ha_cpu_topo *topo)
                }
                putchar('\n');
        }
+
+       printf("CPU clusters:\n");
+       for (cpu = 0; cpu < cpu_topo_maxcpus; cpu++) {
+               if (!ha_cpu_clusters[cpu].nb_cpu)
+                       continue;
+               printf("  %3u  cpus=%3u cores=%3u capa=%u\n",
+                      cpu, ha_cpu_clusters[cpu].nb_cpu,
+                      ha_cpu_clusters[cpu].nb_cores,
+                      ha_cpu_clusters[cpu].capa);
+       }
 }
 
 /* function used by qsort to re-arrange CPUs by index only, to restore original
@@ -680,7 +691,7 @@ void cpu_fixup_topology(void)
  */
 void cpu_compose_clusters(void)
 {
-       int cpu;
+       int cpu, core;
        int curr_gid, prev_gid;
        int curr_lid, prev_lid;
 
@@ -693,6 +704,8 @@ void cpu_compose_clusters(void)
 
        prev_gid = prev_lid = -2; // make sure it cannot match even unassigned ones
        curr_gid = curr_lid = -1;
+       core = -1;
+
        for (cpu = 0; cpu <= cpu_topo_lastcpu; cpu++) {
                /* renumber clusters and assign unassigned ones at the same
                 * time. For this, we'll compare pkg/die/llc with the last
@@ -706,6 +719,7 @@ void cpu_compose_clusters(void)
                    (ha_cpu_topo[cpu].no_id != ha_cpu_topo[cpu-1].no_id)) {
                        curr_gid++;
                        curr_lid = 0;
+                       core = -1;
                }
                else if (ha_cpu_topo[cpu].cl_gid != prev_gid ||
                         ha_cpu_topo[cpu].ca_id[4] != ha_cpu_topo[cpu-1].ca_id[4] ||
@@ -723,6 +737,22 @@ void cpu_compose_clusters(void)
                prev_lid = ha_cpu_topo[cpu].cl_lid;
                ha_cpu_topo[cpu].cl_gid = curr_gid;
                ha_cpu_topo[cpu].cl_lid = curr_lid;
+
+               /* update per-cluster info */
+               if (!(ha_cpu_topo[cpu].st & HA_CPU_F_EXCL_MASK)) {
+                       ha_cpu_clusters[curr_gid].nb_cpu++;
+                       if (ha_cpu_topo[cpu].ts_id != core) {
+                               /* new core for this cluster */
+                               ha_cpu_clusters[curr_gid].nb_cores++;
+                               ha_cpu_clusters[curr_gid].capa += ha_cpu_topo[cpu].capa;
+                               core = ha_cpu_topo[cpu].ts_id;
+                       } else {
+                               /* tests show that it's reasonable to expect
+                                * ~+33% for an extra thread on the same core.
+                                */
+                               ha_cpu_clusters[curr_gid].capa += ha_cpu_topo[cpu].capa / 3;
+                       }
+               }
        }
 
        cpu_reorder_by_index(ha_cpu_topo, cpu_topo_maxcpus);
@@ -1141,13 +1171,22 @@ static int cpu_topo_alloc(void)
        if (!ha_cpu_topo)
                return 0;
 
+       /* allocate the structures used to store CPU topology info */
+       ha_cpu_clusters = (struct ha_cpu_cluster*)malloc(cpu_topo_maxcpus * sizeof(*ha_cpu_clusters));
+       if (!ha_cpu_topo)
+               return 0;
+
        /* preset all fields to -1 except the index and the state flags which
         * are assumed to all be bound and online unless detected otherwise.
+        * Also set all cluster idx to their respective index.
         */
        for (cpu = 0; cpu < cpu_topo_maxcpus; cpu++) {
                memset(&ha_cpu_topo[cpu], 0xff, sizeof(*ha_cpu_topo));
                ha_cpu_topo[cpu].st  = 0;
                ha_cpu_topo[cpu].idx = cpu;
+
+               memset(&ha_cpu_clusters[cpu], 0x0, sizeof(*ha_cpu_clusters));
+               ha_cpu_clusters[cpu].idx = cpu;
        }
 
        /* pre-inizialize the configured CPU sets */
@@ -1164,6 +1203,7 @@ static int cpu_topo_alloc(void)
 
 static void cpu_topo_deinit(void)
 {
+       ha_free(&ha_cpu_clusters);
        ha_free(&ha_cpu_topo);
        ha_free(&cpu_map);
 }