dirty_log_test supports both dirty-bitmap and dirty-ring as dirty-page tracking mechanisms, while dirty_log_perf_test only supports dirty-bitmap.
Add support to dirty-ring on dirty_log_perf_test so it can be used to compare performance between changes in the mechanism. Signed-off-by: Leonardo Bras <[email protected]> --- .../selftests/kvm/dirty_log_perf_test.c | 100 ++++++++++++++++-- 1 file changed, 90 insertions(+), 10 deletions(-) diff --git a/tools/testing/selftests/kvm/dirty_log_perf_test.c b/tools/testing/selftests/kvm/dirty_log_perf_test.c index 69b38791440e..659efa679bc7 100644 --- a/tools/testing/selftests/kvm/dirty_log_perf_test.c +++ b/tools/testing/selftests/kvm/dirty_log_perf_test.c @@ -6,63 +6,115 @@ * * Copyright (C) 2018, Red Hat, Inc. * Copyright (C) 2020, Google, Inc. */ #include <stdio.h> #include <stdlib.h> #include <time.h> #include <pthread.h> #include <linux/bitmap.h> +#include <asm/barrier.h> #include "kvm_util.h" #include "test_util.h" #include "memstress.h" #include "guest_modes.h" #include "ucall_common.h" /* How many host loops to run by default (one KVM_GET_DIRTY_LOG for each loop)*/ #define TEST_HOST_LOOP_N 2UL static int nr_vcpus = 1; static u64 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; +static u32 dirty_ring_size; static bool host_quit; static int iteration; static int vcpu_last_completed_iteration[KVM_MAX_VCPUS]; +static struct timespec vcpu_dirty_ring_collect[KVM_MAX_VCPUS]; + +static void dirty_ring_collect(struct kvm_vcpu *vcpu, u32 *ring_idx, + struct timespec *ts) +{ + struct timespec start; + struct kvm_dirty_gfn *dirty_gfns = vcpu_map_dirty_ring(vcpu); + u32 ret, idx = *ring_idx; + u32 ring_size = vcpu->vm->dirty_ring_size; + + clock_gettime(CLOCK_MONOTONIC, &start); + + while (true) { + struct kvm_dirty_gfn *cur; + + cur = &dirty_gfns[idx % ring_size]; + if (smp_load_acquire(&cur->flags) != KVM_DIRTY_GFN_F_DIRTY) + break; + + smp_store_release(&cur->flags, KVM_DIRTY_GFN_F_RESET); + idx++; + } + + idx -= *ring_idx; + *ring_idx += idx; + + ret = kvm_vm_reset_dirty_ring(vcpu->vm); + + TEST_ASSERT(ret == idx, "Reset dirty pages (%u) mismatch " + "with collected (%u)", ret, idx); + + *ts = timespec_add(*ts, timespec_elapsed(start)); +} static void vcpu_worker(struct memstress_vcpu_args *vcpu_args) { struct kvm_vcpu *vcpu = vcpu_args->vcpu; int vcpu_idx = vcpu_args->vcpu_idx; u64 pages_count = 0; struct kvm_run *run; struct timespec start; struct timespec ts_diff; struct timespec total = (struct timespec){0}; struct timespec avg; + bool use_dirty_ring = !!vcpu->vm->dirty_ring_size; + u32 ring_idx = 0; int ret; run = vcpu->run; while (!READ_ONCE(host_quit)) { int current_iteration = READ_ONCE(iteration); + struct timespec collect = (struct timespec){0}; clock_gettime(CLOCK_MONOTONIC, &start); - ret = _vcpu_run(vcpu); + + do { + ret = _vcpu_run(vcpu); + if (!use_dirty_ring) + break; + + dirty_ring_collect(vcpu, &ring_idx, &collect); + } while (ret == KVM_EXIT_DIRTY_RING_FULL); + ts_diff = timespec_elapsed(start); + if (use_dirty_ring) { + ts_diff = timespec_sub(ts_diff, collect); + vcpu_dirty_ring_collect[vcpu_idx] = collect; + } + TEST_ASSERT(ret == 0, "vcpu_run failed: %d", ret); - TEST_ASSERT(get_ucall(vcpu, NULL) == UCALL_SYNC, + TEST_ASSERT(get_ucall(vcpu, NULL) == UCALL_SYNC || + (use_dirty_ring && run->exit_reason == KVM_EXIT_DIRTY_RING_FULL), "Invalid guest sync status: exit_reason=%s", exit_reason_str(run->exit_reason)); pr_debug("Got sync event from vCPU %d\n", vcpu_idx); vcpu_last_completed_iteration[vcpu_idx] = current_iteration; pr_debug("vCPU %d updated last completed iteration to %d\n", vcpu_idx, vcpu_last_completed_iteration[vcpu_idx]); if (current_iteration) { pages_count += vcpu_args->pages; @@ -112,42 +164,45 @@ static void run_test(enum vm_guest_mode mode, void *arg) struct timespec start; struct timespec ts_diff; struct timespec get_dirty_log_total = (struct timespec){0}; struct timespec vcpu_dirty_total = (struct timespec){0}; struct timespec avg; struct timespec clear_dirty_log_total = (struct timespec){0}; int i; vm = memstress_create_vm(mode, nr_vcpus, guest_percpu_mem_size, p->slots, p->backing_src, - p->partition_vcpu_memory_access, 0); + p->partition_vcpu_memory_access, + dirty_ring_size); memstress_set_write_percent(vm, p->write_percent); guest_num_pages = (nr_vcpus * guest_percpu_mem_size) >> vm->page_shift; guest_num_pages = vm_adjust_num_guest_pages(mode, guest_num_pages); host_num_pages = vm_num_host_pages(mode, guest_num_pages); pages_per_slot = host_num_pages / p->slots; bitmaps = memstress_alloc_bitmaps(p->slots, pages_per_slot); if (dirty_log_manual_caps) vm_enable_cap(vm, KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2, dirty_log_manual_caps); /* Start the iterations */ iteration = 0; host_quit = false; clock_gettime(CLOCK_MONOTONIC, &start); - for (i = 0; i < nr_vcpus; i++) + for (i = 0; i < nr_vcpus; i++) { vcpu_last_completed_iteration[i] = -1; + vcpu_dirty_ring_collect[i] = (struct timespec){0}; + } /* * Use 100% writes during the population phase to ensure all * memory is actually populated and not just mapped to the zero * page. The prevents expensive copy-on-write faults from * occurring during the dirty memory iterations below, which * would pollute the performance results. */ memstress_set_write_percent(vm, 100); memstress_set_random_access(vm, false); @@ -188,20 +243,35 @@ static void run_test(enum vm_guest_mode mode, void *arg) while (READ_ONCE(vcpu_last_completed_iteration[i]) != iteration) ; } ts_diff = timespec_elapsed(start); vcpu_dirty_total = timespec_add(vcpu_dirty_total, ts_diff); pr_info("Iteration %d dirty memory time: %ld.%.9lds\n", iteration, ts_diff.tv_sec, ts_diff.tv_nsec); + if (dirty_ring_size) { + struct timespec iteration_sum = (struct timespec){0}; + + for (i = 0; i < nr_vcpus; i++) + iteration_sum = timespec_add(iteration_sum, + vcpu_dirty_ring_collect[i]); + + pr_info("Iteration %d clear dirty ring time: %ld.%.9lds\n", + iteration, iteration_sum.tv_sec, iteration_sum.tv_nsec); + + clear_dirty_log_total = timespec_add(clear_dirty_log_total, + iteration_sum); + continue; + } + clock_gettime(CLOCK_MONOTONIC, &start); memstress_get_dirty_log(vm, bitmaps, p->slots); ts_diff = timespec_elapsed(start); get_dirty_log_total = timespec_add(get_dirty_log_total, ts_diff); pr_info("Iteration %d get dirty log time: %ld.%.9lds\n", iteration, ts_diff.tv_sec, ts_diff.tv_nsec); if (dirty_log_manual_caps) { clock_gettime(CLOCK_MONOTONIC, &start); @@ -231,46 +301,51 @@ static void run_test(enum vm_guest_mode mode, void *arg) ts_diff.tv_sec, ts_diff.tv_nsec); /* * 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; memstress_join_vcpu_threads(nr_vcpus); - avg = timespec_div(get_dirty_log_total, p->iterations); - pr_info("Get dirty log over %lu iterations took %ld.%.9lds. (Avg %ld.%.9lds/iteration)\n", - p->iterations, get_dirty_log_total.tv_sec, - get_dirty_log_total.tv_nsec, avg.tv_sec, avg.tv_nsec); + if (!dirty_ring_size) { + avg = timespec_div(get_dirty_log_total, p->iterations); + pr_info("Get dirty log over %lu iterations took %ld.%.9lds. (Avg %ld.%.9lds/iteration)\n", + p->iterations, get_dirty_log_total.tv_sec, + get_dirty_log_total.tv_nsec, avg.tv_sec, avg.tv_nsec); + } - if (dirty_log_manual_caps) { + if (dirty_log_manual_caps || dirty_ring_size) { avg = timespec_div(clear_dirty_log_total, p->iterations); pr_info("Clear dirty log over %lu iterations took %ld.%.9lds. (Avg %ld.%.9lds/iteration)\n", p->iterations, clear_dirty_log_total.tv_sec, clear_dirty_log_total.tv_nsec, avg.tv_sec, avg.tv_nsec); } memstress_free_bitmaps(bitmaps, p->slots); memstress_destroy_vm(vm); } static void help(char *name) { puts(""); printf("usage: %s [-h] [-a] [-i iterations] [-p offset] [-g] " "[-m mode] [-n] [-b vcpu bytes] [-v vcpus] [-o] [-r random seed ] [-s mem type]" "[-x memslots] [-w percentage] [-c physical cpus to run test on]\n", name); puts(""); printf(" -a: access memory randomly rather than in order.\n"); printf(" -i: specify iteration counts (default: %"PRIu64")\n", TEST_HOST_LOOP_N); + printf(" -d: specify the size of dirty-ring for tracking dirty pages.\n" + " If non-zero, will cause dirty-ring to be used instead of\n" + " dirty-bitmap. Must be a power of two."); printf(" -g: Do not enable KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2. This\n" " makes KVM_GET_DIRTY_LOG clear the dirty log (i.e.\n" " KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE is not enabled)\n" " and writes will be tracked as soon as dirty logging is\n" " enabled on the memslot (i.e. KVM_DIRTY_LOG_INITIALLY_SET\n" " is not enabled).\n"); printf(" -p: specify guest physical test memory offset\n" " 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"); @@ -313,31 +388,36 @@ int main(int argc, char *argv[]) /* Override the seed to be deterministic by default. */ guest_random_seed = 1; dirty_log_manual_caps = kvm_check_cap(KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2); dirty_log_manual_caps &= (KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE | KVM_DIRTY_LOG_INITIALLY_SET); guest_modes_append_default(); - while ((opt = getopt(argc, argv, "ab:c:eghi:m:nop:r:s:v:x:w:")) != -1) { + while ((opt = getopt(argc, argv, "ab:c:d:eghi:m:nop:r:s:v:x:w:")) != -1) { switch (opt) { case 'a': p.random_access = true; break; case 'b': guest_percpu_mem_size = parse_size(optarg); break; case 'c': pcpu_list = optarg; break; + case 'd': + dirty_ring_size = parse_size(optarg); + dirty_ring_size *= sizeof(struct kvm_dirty_gfn); + dirty_log_manual_caps = 0; + break; case 'e': /* 'e' is for evil. */ run_vcpus_while_disabling_dirty_logging = true; break; case 'g': dirty_log_manual_caps = 0; break; case 'h': help(argv[0]); break; -- 2.54.0
