diff options
| -rw-r--r-- | tools/testing/selftests/kvm/dirty_log_perf_test.c | 30 |
1 files changed, 27 insertions, 3 deletions
diff --git a/tools/testing/selftests/kvm/dirty_log_perf_test.c b/tools/testing/selftests/kvm/dirty_log_perf_test.c index 808a36dbf0c0..f99e39a672d3 100644 --- a/tools/testing/selftests/kvm/dirty_log_perf_test.c +++ b/tools/testing/selftests/kvm/dirty_log_perf_test.c @@ -59,6 +59,7 @@ static void arch_cleanup_vm(struct kvm_vm *vm) static int nr_vcpus = 1; static uint64_t guest_percpu_mem_size = DEFAULT_PER_VCPU_MEM_SIZE; +static bool run_vcpus_while_disabling_dirty_logging; /* Host variables */ static u64 dirty_log_manual_caps; @@ -109,8 +110,13 @@ static void vcpu_worker(struct perf_test_vcpu_args *vcpu_args) ts_diff.tv_nsec); } + /* + * Keep running the guest while dirty logging is being disabled + * (iteration is negative) so that vCPUs are accessing memory + * for the entire duration of zapping collapsible SPTEs. + */ while (current_iteration == READ_ONCE(iteration) && - !READ_ONCE(host_quit)) {} + READ_ONCE(iteration) >= 0 && !READ_ONCE(host_quit)) {} } avg = timespec_div(total, vcpu_last_completed_iteration[vcpu_idx]); @@ -302,6 +308,14 @@ static void run_test(enum vm_guest_mode mode, void *arg) } } + /* + * Run vCPUs while dirty logging is being disabled to stress disabling + * in terms of both performance and correctness. Opt-in via command + * line as this significantly increases time to disable dirty logging. + */ + if (run_vcpus_while_disabling_dirty_logging) + WRITE_ONCE(iteration, -1); + /* Disable dirty logging */ clock_gettime(CLOCK_MONOTONIC, &start); disable_dirty_logging(vm, p->slots); @@ -309,7 +323,11 @@ static void run_test(enum vm_guest_mode mode, void *arg) pr_info("Disabling dirty logging time: %ld.%.9lds\n", ts_diff.tv_sec, ts_diff.tv_nsec); - /* Tell the vcpu thread to quit */ + /* + * Tell the vCPU threads to quit. No need to manually check that vCPUs + * have stopped running after disabling dirty logging, the join will + * wait for them to exit. + */ host_quit = true; perf_test_join_vcpu_threads(nr_vcpus); @@ -349,6 +367,9 @@ static void help(char *name) " Warning: a low offset can conflict with the loaded test code.\n"); guest_modes_help(); printf(" -n: Run the vCPUs in nested mode (L2)\n"); + printf(" -e: Run vCPUs while dirty logging is being disabled. This\n" + " can significantly increase runtime, especially if there\n" + " isn't a dedicated pCPU for the main thread.\n"); printf(" -b: specify the size of the memory region which should be\n" " dirtied by each vCPU. e.g. 10M or 3G.\n" " (default: 1G)\n"); @@ -385,8 +406,11 @@ int main(int argc, char *argv[]) guest_modes_append_default(); - while ((opt = getopt(argc, argv, "ghi:p:m:nb:f:v:os:x:")) != -1) { + while ((opt = getopt(argc, argv, "eghi:p:m:nb:f:v:os:x:")) != -1) { switch (opt) { + case 'e': + /* 'e' is for evil. */ + run_vcpus_while_disabling_dirty_logging = true; case 'g': dirty_log_manual_caps = 0; break; |