Right now cyclictest acts as if it owns the machine. If you don't
specify the affinity with -a [CPUSET] it will run threads on all cpus.
Change this to only run on cpus according to the affinity.
For example.
taskset -c 0-3 ./cyclictest -t
will only affect the main thread and limit it that to cpus 0-3 but the
threads that are spun off can run anywhere, with this change all threads
will be limited to cpus 0-3
Signed-off-by: John Kacur <jkacur@xxxxxxxxxx>
---
src/cyclictest/cyclictest.c | 39 ++++++++++++++++++++++++++++++++++---
1 file changed, 36 insertions(+), 3 deletions(-)
diff --git a/src/cyclictest/cyclictest.c b/src/cyclictest/cyclictest.c
index 18c383689dc2..ce93ad0643cd 100644
--- a/src/cyclictest/cyclictest.c
+++ b/src/cyclictest/cyclictest.c
@@ -1040,7 +1040,8 @@ static unsigned int is_cpumask_zero(const struct bitmask *mask)
return (rt_numa_bitmask_count(mask) == 0);
}
-static int cpu_for_thread(int thread_num, int max_cpus)
+/* cpu_for_thread AFFINITY_SPECIFIED */
+static int cpu_for_thread_sp(int thread_num, int max_cpus)
{
unsigned int m, cpu, i, num_cpus;
num_cpus = rt_numa_bitmask_count(affinity_mask);
@@ -1059,6 +1060,36 @@ static int cpu_for_thread(int thread_num, int max_cpus)
return 0;
}
+/* cpu_for_thread AFFINITY_USEALL */
+static int cpu_for_thread_ua(int thread_num, int max_cpus)
+{
+ int res, num_cpus, i, m, cpu;
+ pthread_t thread;
+ cpu_set_t cpuset;
+
+ thread = pthread_self();
+ CPU_ZERO(&cpuset);
+
+ 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);
+ m = thread_num % num_cpus;
+
+ for (i = 0, cpu = 0; i < max_cpus; i++) {
+ if (CPU_ISSET(i, &cpuset)) {
+ if (cpu == m)
+ return i;
+ cpu++;
+ }
+ }
+
+ fprintf(stderr, "Bug in cpu mask handling code.\n");
+ return 0;
+}
+
static void parse_cpumask(const char *option, const int max_cpus)
{
@@ -2086,11 +2117,13 @@ int main(int argc, char **argv)
switch (setaffinity) {
case AFFINITY_UNSPECIFIED: cpu = -1; break;
case AFFINITY_SPECIFIED:
- cpu = cpu_for_thread(i, max_cpus);
+ cpu = cpu_for_thread_sp(i, max_cpus);
if (verbose)
printf("Thread %d using cpu %d.\n", i, cpu);
break;
- case AFFINITY_USEALL: cpu = i % max_cpus; break;
+ case AFFINITY_USEALL:
+ cpu = cpu_for_thread_ua(i, max_cpus);
+ break;
default: cpu = -1;
}
--
2.20.1
