Fix -t without a specified [NUM] to run the same number of threads as
available processors.
Currently it runs the same number of threads as cpus on a system.
However, if cyclictest is contrained to run on a smaller set of cpus
either because of a container or a user specified affinity or a
combination of the two, then the actual number of available cpus is
smaller. -t should reflect that.
Signed-off-by: John Kacur <jkacur@xxxxxxxxxx>
---
src/cyclictest/cyclictest.c | 36 ++++++++++++++++++++++++++++++++++--
1 file changed, 34 insertions(+), 2 deletions(-)
diff --git a/src/cyclictest/cyclictest.c b/src/cyclictest/cyclictest.c
index f8df4c6954ad..c5f1fd46567a 100644
--- a/src/cyclictest/cyclictest.c
+++ b/src/cyclictest/cyclictest.c
@@ -1040,6 +1040,35 @@ static unsigned int is_cpumask_zero(const struct bitmask *mask)
return (rt_numa_bitmask_count(mask) == 0);
}
+/* Get available cpus according to getaffinity or according to the
+ * intersection of getaffinity and the user specified affinity
+ * in the case of AFFINITY_SPECIFIED, the function has to be called
+ * after the call to parse_cpumask made in process_options()
+ */
+static int get_available_cpus(void)
+{
+ int num_cpus = 0;
+ int res;
+ pthread_t thread;
+ cpu_set_t cpuset;
+
+
+ if (affinity_mask != NULL) {
+ num_cpus = rt_numa_bitmask_count(affinity_mask);
+ } else {
+ CPU_ZERO(&cpuset);
+ thread = pthread_self();
+ res = pthread_getaffinity_np(thread, sizeof(cpu_set_t), &cpuset);
+ if (res != 0) {
+ fatal("pthread_getaffinity_np failed: %s\n", strerror(res));
+ }
+ num_cpus = CPU_COUNT(&cpuset);
+ }
+
+ return num_cpus;
+
+}
+
/* cpu_for_thread AFFINITY_SPECIFIED */
static int cpu_for_thread_sp(int thread_num, int max_cpus)
{
@@ -1358,7 +1387,7 @@ static void process_options (int argc, char *argv[], int max_cpus)
if (numa)
fatal("numa and smp options are mutually exclusive\n");
smp = 1;
- num_threads = max_cpus;
+ num_threads = -1; /* update after parsing */
setaffinity = AFFINITY_USEALL;
break;
case 't':
@@ -1372,7 +1401,7 @@ static void process_options (int argc, char *argv[], int max_cpus)
else if (optind<argc && atoi(argv[optind]))
num_threads = atoi(argv[optind]);
else
- num_threads = max_cpus;
+ num_threads = -1; /* update after parsing */
break;
case OPT_TRIGGER:
trigger = atoi(optarg);
@@ -1485,6 +1514,9 @@ static void process_options (int argc, char *argv[], int max_cpus)
if (priority < 0 || priority > 99)
error = 1;
+ if (num_threads == -1)
+ num_threads = get_available_cpus();
+
if (priospread && priority == 0) {
fprintf(stderr, "defaulting realtime priority to %d\n",
num_threads+1);
--
2.20.1
