diff options
| -rw-r--r-- | tools/testing/selftests/kvm/rseq_test.c | 35 |
1 files changed, 33 insertions, 2 deletions
diff --git a/tools/testing/selftests/kvm/rseq_test.c b/tools/testing/selftests/kvm/rseq_test.c index 28f97fb520441..ff365b9f47fd5 100644 --- a/tools/testing/selftests/kvm/rseq_test.c +++ b/tools/testing/selftests/kvm/rseq_test.c @@ -186,12 +186,35 @@ static void calc_min_max_cpu(void) "Only one usable CPU, task migration not possible"); } +static void help(const char *name) +{ + puts(""); + printf("usage: %s [-h] [-u]\n", name); + printf(" -u: Don't sanity check the number of successful KVM_RUNs\n"); + puts(""); + exit(0); +} + int main(int argc, char *argv[]) { + bool skip_sanity_check = false; int r, i, snapshot; struct kvm_vm *vm; struct kvm_vcpu *vcpu; u32 cpu, rseq_cpu; + int opt; + + while ((opt = getopt(argc, argv, "hu")) != -1) { + switch (opt) { + case 'u': + skip_sanity_check = true; + break; + case 'h': + default: + help(argv[0]); + break; + } + } r = sched_getaffinity(0, sizeof(possible_mask), &possible_mask); TEST_ASSERT(!r, "sched_getaffinity failed, errno = %d (%s)", errno, @@ -254,9 +277,17 @@ int main(int argc, char *argv[]) * getcpu() to stabilize. A 2:1 migration:KVM_RUN ratio is a fairly * conservative ratio on x86-64, which can do _more_ KVM_RUNs than * migrations given the 1us+ delay in the migration task. + * + * Another reason why it may have small migration:KVM_RUN ratio is that, + * on systems with large low power mode wakeup latency, it may happen + * quite often that the scheduler is not able to wake up the target CPU + * before the vCPU thread is scheduled to another CPU. */ - TEST_ASSERT(i > (NR_TASK_MIGRATIONS / 2), - "Only performed %d KVM_RUNs, task stalled too much?", i); + TEST_ASSERT(skip_sanity_check || i > (NR_TASK_MIGRATIONS / 2), + "Only performed %d KVM_RUNs, task stalled too much?\n\n" + " Try disabling deep sleep states to reduce CPU wakeup latency,\n" + " e.g. via cpuidle.off=1 or setting /dev/cpu_dma_latency to '0',\n" + " or run with -u to disable this sanity check.", i); pthread_join(migration_thread, NULL); |