1berry/haproxy
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

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

Browse Source 
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.
This commit is contained in:
Willy Tarreau 2025-03-14 16:08:04 +01:00
parent 204ac3c0b6
commit aa4776210b
2 changed files with 49 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
include/haproxy/cpu_topo-t.h
View File

@ -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 */

42
src/cpu_topo.c
View File

@ -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);
}