use_current_cpuset() function does:
/*
* After this function is called, affinity_mask is the intersection of
* the user supplied affinity mask and the affinity mask from the run
* time environment
*/
static void use_current_cpuset(int max_cpus, struct bitmask *cpumask)
However, when using isolcpus kernel command line option, the CPUs
specificied at isolcpus= are not part of the run time environment
cpumask.
This causes "cyclictest -a isolatedcpus" to fail with:
WARN: Couldn't setaffinity in main thread: Invalid argument
FATAL: No allowable cpus to run on
# /dev/cpu_dma_latency set to 0us
To fix this, add an environment variable IGNORE_RUNTIME_CPU_AFFINITY_MASK
that when set to a value other than 0, will override the runtime cpu
affinity mask (retrieved with numa_sched_getaffinity) with a bit set
for each CPU in numa_num_configured_cpus:
numa_num_configured_cpus() returns the number of cpus in the system.
This count includes any cpus that are currently disabled. This count is
derived from the cpu numbers in /sys/devices/system/cpu. If the kernel
is configured without /sys (CONFIG_SYSFS=n) then it falls back to using
the number of online cpus.
Signed-off-by: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
diff --git a/src/lib/rt-numa.c b/src/lib/rt-numa.c
index ee5ab99..3106f1e 100644
--- a/src/lib/rt-numa.c
+++ b/src/lib/rt-numa.c
@@ -9,6 +9,7 @@
#include <errno.h>
#include <sched.h>
#include <pthread.h>
+#include <stdlib.h>
#include "rt-error.h"
#include "rt-numa.h"
@@ -99,11 +100,20 @@ int cpu_for_thread_ua(int thread_num, int max_cpus)
static void use_current_cpuset(int max_cpus, struct bitmask *cpumask)
{
struct bitmask *curmask;
+ char *ignore_affinity_mask;
int i;
curmask = numa_allocate_cpumask();
numa_sched_getaffinity(getpid(), curmask);
+ ignore_affinity_mask = getenv("IGNORE_RUNTIME_CPU_AFFINITY_MASK");
+ if (ignore_affinity_mask && *ignore_affinity_mask != '0') {
+ int conf_cpus = numa_num_configured_cpus();
+
+ for (i = 0; i < conf_cpus; i++)
+ numa_bitmask_setbit(curmask, i);
+ }
+
/*
* Clear bits that are not set in both the cpuset from the
* environment, and in the user specified affinity.
