[PATCH] cyclictest: Fix --affinity when intermediate CPUs are offline
From: Jonathan Schwender <hidden>
Date: 2021-01-14 11:51:41
Subsystem:
the rest · Maintainer:
Linus Torvalds
Use max_cpus = sysconf(_SC_NPROCESSORS_CONF) to determine the number of the maximum CPU (+1). The cpu_for_thread_*() functions check the first max_cpus bits in the cpuset / cpumask. This fixes failing to set the affinity to CPUs >= num_online_cpus, if some intermediate CPU is offline, e.g. on an AMD system with nosmt. Signed-off-by: Jonathan Schwender <redacted> --- src/cyclictest/cyclictest.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/src/cyclictest/cyclictest.c b/src/cyclictest/cyclictest.c
index f38c453..b104e4c 100644
--- a/src/cyclictest/cyclictest.c
+++ b/src/cyclictest/cyclictest.c@@ -1741,7 +1741,8 @@ int main(int argc, char **argv) int signum = SIGALRM; int mode; int cpu; - int max_cpus = sysconf(_SC_NPROCESSORS_ONLN); + int max_cpus = sysconf(_SC_NPROCESSORS_CONF); + int online_cpus = sysconf(_SC_NPROCESSORS_ONLN); int i, ret = -1; int status;
@@ -1750,8 +1751,10 @@ int main(int argc, char **argv) if (check_privs()) exit(EXIT_FAILURE); - if (verbose) + if (verbose) { printf("Max CPUs = %d\n", max_cpus); + printf("Online CPUs = %d\n", online_cpus); + } /* Restrict the main pid to the affinity specified by the user */ if (affinity_mask != NULL) {
--
2.29.2