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Subject[PATCH v2 1/3] perf bench numa: use numa_node_to_cpus() to bind tasks to nodes
Date
It is currently assumed that each node contains at most
nr_cpus/nr_nodes CPUs and node CPU ranges do not overlap.
That assumption is generally incorrect as there are archs
where a CPU number does not depend on to its node number.

This update removes the described assumption by simply calling
numa_node_to_cpus() interface and using the returned mask for
binding CPUs to nodes. It also tightens a cpumask allocation
failure check a bit.

Cc: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Balamuruhan S <bala24@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
---
tools/perf/bench/numa.c | 27 +++++++++++++--------------
1 file changed, 13 insertions(+), 14 deletions(-)

diff --git a/tools/perf/bench/numa.c b/tools/perf/bench/numa.c
index 5797253..23e224e 100644
--- a/tools/perf/bench/numa.c
+++ b/tools/perf/bench/numa.c
@@ -247,12 +247,13 @@ static int is_node_present(int node)
*/
static bool node_has_cpus(int node)
{
- struct bitmask *cpu = numa_allocate_cpumask();
+ struct bitmask *cpumask = numa_allocate_cpumask();
unsigned int i;

- if (cpu && !numa_node_to_cpus(node, cpu)) {
- for (i = 0; i < cpu->size; i++) {
- if (numa_bitmask_isbitset(cpu, i))
+ BUG_ON(!cpumask);
+ if (!numa_node_to_cpus(node, cpumask)) {
+ for (i = 0; i < cpumask->size; i++) {
+ if (numa_bitmask_isbitset(cpumask, i))
return true;
}
}
@@ -288,14 +289,10 @@ static cpu_set_t bind_to_cpu(int target_cpu)

static cpu_set_t bind_to_node(int target_node)
{
- int cpus_per_node = g->p.nr_cpus / nr_numa_nodes();
cpu_set_t orig_mask, mask;
int cpu;
int ret;

- BUG_ON(cpus_per_node * nr_numa_nodes() != g->p.nr_cpus);
- BUG_ON(!cpus_per_node);
-
ret = sched_getaffinity(0, sizeof(orig_mask), &orig_mask);
BUG_ON(ret);

@@ -305,13 +302,15 @@ static cpu_set_t bind_to_node(int target_node)
for (cpu = 0; cpu < g->p.nr_cpus; cpu++)
CPU_SET(cpu, &mask);
} else {
- int cpu_start = (target_node + 0) * cpus_per_node;
- int cpu_stop = (target_node + 1) * cpus_per_node;
-
- BUG_ON(cpu_stop > g->p.nr_cpus);
+ struct bitmask *cpumask = numa_allocate_cpumask();

- for (cpu = cpu_start; cpu < cpu_stop; cpu++)
- CPU_SET(cpu, &mask);
+ BUG_ON(!cpumask);
+ if (!numa_node_to_cpus(target_node, cpumask)) {
+ for (cpu = 0; cpu < (int)cpumask->size; cpu++) {
+ if (numa_bitmask_isbitset(cpumask, cpu))
+ CPU_SET(cpu, &mask);
+ }
+ }
}

ret = sched_setaffinity(0, sizeof(mask), &mask);
--
1.8.3.1
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