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MINOR: cpu-topo: implement a CPU sorting mechanism by cluster ID

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This will be used to detect and fix incorrect setups which report
the same cluster ID for multiple L3 instances.

The arrangement of functions in this file is becoming a real problem.
Maybe we should move all this to cpu_topo for example, and better
distinguish OS-specific and generic code.
This commit is contained in:
Willy Tarreau 2025-01-10 19:32:02 +01:00
parent a8acdbd9fd
commit a4471ea56d
2 changed files with 66 additions and 0 deletions
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4
include/haproxy/cpu_topo.h
View File

@ -51,10 +51,14 @@ void cpu_reorder_by_locality(struct ha_cpu_topo *topo, int entries);
*/
void cpu_reorder_by_index(struct ha_cpu_topo *topo, int entries);
/* re-order a CPU topology array by cluster id. */
void cpu_reorder_by_cluster(struct ha_cpu_topo *topo, int entries);
/* Functions used by qsort to compare hardware CPUs (not meant to be used from
* outside cpu_topo).
*/
int _cmp_cpu_index(const void *a, const void *b);
int _cmp_cpu_locality(const void *a, const void *b);
int _cmp_cpu_cluster(const void *a, const void *b);
#endif /* _HAPROXY_CPU_TOPO_H */

62
src/cpu_topo.c
View File

@ -322,6 +322,62 @@ int _cmp_cpu_locality(const void *a, const void *b)
return 0;
}
/* function used by qsort to compare two hwcpus and arrange them by cluster to
* make sure no cluster crosses L3 boundaries. -1 says a<b, 1 says a>b. It's
* only used during topology detection.
*/
int _cmp_cpu_cluster(const void *a, const void *b)
{
const struct ha_cpu_topo *l = (const struct ha_cpu_topo *)a;
const struct ha_cpu_topo *r = (const struct ha_cpu_topo *)b;
/* first, online vs offline */
if (!(l->st & HA_CPU_F_EXCL_MASK) && (r->st & HA_CPU_F_EXCL_MASK))
return -1;
if (!(r->st & HA_CPU_F_EXCL_MASK) && (l->st & HA_CPU_F_EXCL_MASK))
return 1;
/* next, cluster */
if (l->cl_gid >= 0 && l->cl_gid < r->cl_gid)
return -1;
if (l->cl_gid > r->cl_gid && r->cl_gid >= 0)
return 1;
/* next, package ID */
if (l->pk_id >= 0 && l->pk_id < r->pk_id)
return -1;
if (l->pk_id > r->pk_id && r->pk_id >= 0)
return 1;
/* next, node ID */
if (l->no_id >= 0 && l->no_id < r->no_id)
return -1;
if (l->no_id > r->no_id && r->no_id >= 0)
return 1;
/* next, L3 */
if (l->ca_id[3] >= 0 && l->ca_id[3] < r->ca_id[3])
return -1;
if (l->ca_id[3] > r->ca_id[3] && r->ca_id[3] >= 0)
return 1;
/* if no L3, then L2 */
if (l->ca_id[2] >= 0 && l->ca_id[2] < r->ca_id[2])
return -1;
if (l->ca_id[2] > r->ca_id[2] && r->ca_id[2] >= 0)
return 1;
/* next, IDX, so that SMT ordering is preserved */
if (l->idx >= 0 && l->idx < r->idx)
return -1;
if (l->idx > r->idx && r->idx >= 0)
return 1;
/* exactly the same (e.g. absent) */
return 0;
}
/* re-order a CPU topology array by CPU index only. This is mostly used before
* listing CPUs regardless of their characteristics.
*/
@ -336,6 +392,12 @@ void cpu_reorder_by_locality(struct ha_cpu_topo *topo, int entries)
qsort(topo, entries, sizeof(*topo), _cmp_cpu_locality);
}
/* re-order a CPU topology array by cluster id. */
void cpu_reorder_by_cluster(struct ha_cpu_topo *topo, int entries)
{
qsort(topo, entries, sizeof(*topo), _cmp_cpu_cluster);
}
/* returns an optimal maxcpus for the current system. It will take into
* account what is reported by the OS, if any, otherwise will fall back
* to the cpuset size, which serves as an upper limit in any case.