KVM: selftests: Fix population stage in dirty_log_perf_test

Currently the population stage in the dirty_log_perf_test does nothing
as the per-vCPU iteration counters are not initialized and the loop does
not wait for each vCPU. Remedy those errors.

Reviewed-by: Jacob Xu <jacobhxu@google.com>
Reviewed-by: Makarand Sonare <makarandsonare@google.com>
Signed-off-by: Ben Gardon <bgardon@google.com>
Message-Id: <20210112214253.463999-5-bgardon@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/tools/testing/selftests/kvm/dirty_log_perf_test.c b/tools/testing/selftests/kvm/dirty_log_perf_test.c
index 3875f22..fb6eb7f 100644 (file)
--- a/tools/testing/selftests/kvm/dirty_log_perf_test.c
+++ b/tools/testing/selftests/kvm/dirty_log_perf_test.c
@@ -139,14 +139,19 @@ static void run_test(enum vm_guest_mode mode, void *arg)
 
        clock_gettime(CLOCK_MONOTONIC, &start);
        for (vcpu_id = 0; vcpu_id < nr_vcpus; vcpu_id++) {
+               vcpu_last_completed_iteration[vcpu_id] = -1;
+
                pthread_create(&vcpu_threads[vcpu_id], NULL, vcpu_worker,
                               &perf_test_args.vcpu_args[vcpu_id]);
        }
 
-       /* Allow the vCPU to populate memory */
+       /* Allow the vCPUs to populate memory */
        pr_debug("Starting iteration %d - Populating\n", iteration);
-       while (READ_ONCE(vcpu_last_completed_iteration[vcpu_id]) != iteration)
-               ;
+       for (vcpu_id = 0; vcpu_id < nr_vcpus; vcpu_id++) {
+               while (READ_ONCE(vcpu_last_completed_iteration[vcpu_id]) !=
+                      iteration)
+                       ;
+       }
 
        ts_diff = timespec_elapsed(start);
        pr_info("Populate memory time: %ld.%.9lds\n",