[patch v4] rt-tests: add task isolation activation to cyclictest/oslat

From: Marcelo Tosatti
Date: Fri Oct 08 2021 - 10:50:03 EST




Check whether task isolation is configured, right before the latency
sensitive loop, and if so, activate it.

Use chisol util-linux tool to configure task isolation externally.

Signed-off-by: Marcelo Tosatti <mtosatti@xxxxxxxxxx>

diff --git a/src/cyclictest/cyclictest.c b/src/cyclictest/cyclictest.c
index 2187d98..2e13046 100644
--- a/src/cyclictest/cyclictest.c
+++ b/src/cyclictest/cyclictest.c
@@ -515,10 +515,13 @@ static void *timerthread(void *param)
struct itimerval itimer;
struct itimerspec tspec;
struct thread_stat *stat = par->stats;
- int stopped = 0;
+ int stopped = 0, ret = 0;
cpu_set_t mask;
pthread_t thread;
unsigned long smi_now, smi_old = 0;
+#ifdef PR_ISOL_CFG_GET
+ unsigned long long isol_mask = 0;
+#endif

memset(&stop, 0, sizeof(stop));

@@ -623,11 +626,20 @@ static void *timerthread(void *param)

stat->threadstarted++;

+#ifdef PR_ISOL_CFG_GET
+ ret = prctl(PR_ISOL_CFG_GET, I_CFG_FEAT, 0, &isol_mask, 0);
+ if (ret != -1 && isol_mask != 0) {
+ ret = prctl(PR_ISOL_ACTIVATE_SET, &isol_mask, 0, 0);
+ if (ret == -1)
+ fatal("prctl PR_ISOL_ACTIVATE_SET");
+ }
+#endif
+
while (!shutdown) {

uint64_t diff;
unsigned long diff_smi = 0;
- int sigs, ret;
+ int sigs;

/* Wait for next period */
switch (par->mode) {
@@ -775,6 +787,14 @@ static void *timerthread(void *param)
}

out:
+#ifdef PR_ISOL_ACTIVATE_SET
+ if (isol_mask != 0) {
+ ret = prctl(PR_ISOL_ACTIVATE_SET, &isol_mask, 0, 0);
+ if (ret == -1)
+ fatal("prctl PR_ISOL_ACTIVATE_SET");
+ }
+#endif
+
if (refresh_on_max) {
pthread_mutex_lock(&refresh_on_max_lock);
/* We could reach here with both shutdown and allstopped unset (0).
diff --git a/src/oslat/oslat.c b/src/oslat/oslat.c
index 50ddc81..2105af0 100644
--- a/src/oslat/oslat.c
+++ b/src/oslat/oslat.c
@@ -31,6 +31,7 @@
#include <limits.h>
#include <stdbool.h>

+#include <linux/prctl.h>
#include <sys/prctl.h>
#include <sys/stat.h>
#include <sys/sysinfo.h>
@@ -383,9 +384,20 @@ static void insert_bucket(struct thread *t, stamp_t value)

static void doit(struct thread *t)
{
+#ifdef PR_ISOL_CFG_GET
+ int ret;
+ unsigned long long isol_mask;
+#endif
+
stamp_t ts1, ts2;
workload_fn workload_fn = g.workload->w_fn;

+#ifdef PR_ISOL_CFG_GET
+ ret = prctl(PR_ISOL_CFG_GET, I_CFG_FEAT, 0, &isol_mask, 0);
+ if (ret != -1 && isol_mask != 0)
+ TEST0(prctl(PR_ISOL_ACTIVATE_SET, &isol_mask, 0, 0, 0));
+#endif
+
frc(&ts2);
do {
workload_fn(t->dst_buf, t->src_buf, g.workload_mem_size);
@@ -393,6 +405,13 @@ static void doit(struct thread *t)
insert_bucket(t, ts1 - ts2);
ts2 = ts1;
} while (g.cmd == GO);
+
+#ifdef PR_ISOL_CFG_GET
+ if (isol_mask != 0) {
+ isol_mask = 0;
+ TEST0(prctl(PR_ISOL_ACTIVATE_SET, &isol_mask, 0, 0, 0));
+ }
+#endif
}

static int set_fifo_prio(int prio)