Commit 6190741c authored by Robin Murphy's avatar Robin Murphy Committed by Will Deacon
Browse files

perf/arm-cmn: Account for NUMA affinity 



On a system with multiple CMN meshes, ideally we'd want to access each
PMU from within its own mesh, rather than with a long CML round-trip,
wherever feasible. Since such a system is likely to be presented as
multiple NUMA nodes, let's also hope a proximity domain is specified
for each CMN programming interface, and use that to guide our choice
of IRQ affinity to favour a node-local CPU where possible.

Signed-off-by: default avatarRobin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/32438b0d016e0649d882d47d30ac2000484287b9.1638530442.git.robin.murphy@arm.com


Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent 56c7c6ea

drivers/perf/arm-cmn.c

+38 −13
Original line number Diff line number Diff line
@@ -1147,23 +1147,47 @@ static int arm_cmn_commit_txn(struct pmu *pmu) 
	return 0;

}



static int arm_cmn_pmu_offline_cpu(unsigned int cpu, struct hlist_node *node)

static void arm_cmn_migrate(struct arm_cmn *cmn, unsigned int cpu)

{

	unsigned int i;



	perf_pmu_migrate_context(&cmn->pmu, cmn->cpu, cpu);

	for (i = 0; i < cmn->num_dtcs; i++)

		irq_set_affinity(cmn->dtc[i].irq, cpumask_of(cpu));

	cmn->cpu = cpu;

}



static int arm_cmn_pmu_online_cpu(unsigned int cpu, struct hlist_node *cpuhp_node)

{

	struct arm_cmn *cmn;

	unsigned int i, target;

	int node;



	cmn = hlist_entry_safe(node, struct arm_cmn, cpuhp_node);

	if (cpu != cmn->cpu)

	cmn = hlist_entry_safe(cpuhp_node, struct arm_cmn, cpuhp_node);

	node = dev_to_node(cmn->dev);

	if (node != NUMA_NO_NODE && cpu_to_node(cmn->cpu) != node && cpu_to_node(cpu) == node)

		arm_cmn_migrate(cmn, cpu);

	return 0;

}



	target = cpumask_any_but(cpu_online_mask, cpu);

	if (target >= nr_cpu_ids)

static int arm_cmn_pmu_offline_cpu(unsigned int cpu, struct hlist_node *cpuhp_node)

{

	struct arm_cmn *cmn;

	unsigned int target;

	int node;

	cpumask_t mask;



	cmn = hlist_entry_safe(cpuhp_node, struct arm_cmn, cpuhp_node);

	if (cpu != cmn->cpu)

		return 0;



	perf_pmu_migrate_context(&cmn->pmu, cpu, target);

	for (i = 0; i < cmn->num_dtcs; i++)

		irq_set_affinity(cmn->dtc[i].irq, cpumask_of(target));

	cmn->cpu = target;

	node = dev_to_node(cmn->dev);

	if (cpumask_and(&mask, cpumask_of_node(node), cpu_online_mask) &&

	    cpumask_andnot(&mask, &mask, cpumask_of(cpu)))

		target = cpumask_any(&mask);

	else

		target = cpumask_any_but(cpu_online_mask, cpu);

	if (target < nr_cpu_ids)

		arm_cmn_migrate(cmn, target);

	return 0;

}
@@ -1532,7 +1556,7 @@ static int arm_cmn_probe(struct platform_device *pdev) 
	if (err)

		return err;



	cmn->cpu = raw_smp_processor_id();

	cmn->cpu = cpumask_local_spread(0, dev_to_node(cmn->dev));

	cmn->pmu = (struct pmu) {

		.module = THIS_MODULE,

		.attr_groups = arm_cmn_attr_groups,
@@ -1608,7 +1632,8 @@ static int __init arm_cmn_init(void) 
	int ret;



	ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN,

				      "perf/arm/cmn:online", NULL,

				      "perf/arm/cmn:online",

				      arm_cmn_pmu_online_cpu,

				      arm_cmn_pmu_offline_cpu);

	if (ret < 0)

		return ret;