perf bench: Fix numa testcase to check if CPU used to bind task is online

Perf numa bench test fails with error:

Testcase:

  ./perf bench numa mem -p 2 -t 1 -P 1024 -C 0,8 -M 1,0 -s 20 -zZq --thp  1 --no-data_rand_walk

Failure snippet:

<<>>
  Running 'numa/mem' benchmark:

  # Running main, "perf bench numa numa-mem -p 2 -t 1 -P 1024 -C 0,8 -M 1,0 -s 20 -zZq --thp 1 --no-data_rand_walk"

  perf: bench/numa.c:333: bind_to_cpumask: Assertion `!(ret)' failed.
<<>>

The Testcases uses CPU's 0 and 8. In function "parse_setup_cpu_list",
There is check to see if cpu number is greater than max cpu's possible
in the system ie via "if (bind_cpu_0 >= g->p.nr_cpus || bind_cpu_1 >=
g->p.nr_cpus) {".

But it could happen that system has say 48 CPU's, but only number of
online CPU's is 0-7. Other CPU's are offlined. Since "g->p.nr_cpus" is
48, so function will go ahead and set bit for CPU 8 also in cpumask (
td->bind_cpumask).

bind_to_cpumask function is called to set affinity using
sched_setaffinity and the cpumask. Since the CPU8 is not present, set
affinity will fail here with EINVAL.

Fix this issue by adding a check to make sure that, CPU's provided in
the input argument values are online before proceeding further and skip
the test. For this, include new helper function "is_cpu_online" in
"tools/perf/util/header.c".

Since "BIT(x)" definition will get included from header.h, remove
that from bench/numa.c

Reported-by: Disha Goel <disgoel@linux.vnet.ibm.com>
Signed-off-by: Athira Jajeev <atrajeev@linux.vnet.ibm.com>
Tested-by: Disha Goel <disgoel@linux.vnet.ibm.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nageswara R Sastry <rnsastry@linux.ibm.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: https://lore.kernel.org/r/20220412164059.42654-2-atrajeev@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 6 insertions, 2 deletions

diff --git a/tools/perf/bench/numa.c b/tools/perf/bench/numa.c
index f2640179ada9..c838c248aa2c 100644
--- a/tools/perf/bench/numa.c
+++ b/tools/perf/bench/numa.c
@@ -34,6 +34,7 @@
 #include <linux/numa.h>
 #include <linux/zalloc.h>
 
+#include "../util/header.h"
 #include <numa.h>
 #include <numaif.h>
 
@@ -585,6 +586,11 @@ static int parse_setup_cpu_list(void)
 			return -1;
 		}
 
+		if (is_cpu_online(bind_cpu_0) != 1 || is_cpu_online(bind_cpu_1) != 1) {
+			printf("\nTest not applicable, bind_cpu_0 or bind_cpu_1 is offline\n");
+			return -1;
+		}
+
 		BUG_ON(bind_cpu_0 < 0 || bind_cpu_1 < 0);
 		BUG_ON(bind_cpu_0 > bind_cpu_1);
 
@@ -752,8 +758,6 @@ static int parse_nodes_opt(const struct option *opt __maybe_unused,
 	return parse_node_list(arg);
 }
 
-#define BIT(x) (1ul << x)
-
 static inline uint32_t lfsr_32(uint32_t lfsr)
 {
 	const uint32_t taps = BIT(1) | BIT(5) | BIT(6) | BIT(31);