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1// SPDX-License-Identifier: GPL-2.02/*3 * KVM dirty page logging performance test4 *5 * Based on dirty_log_test.c6 *7 * Copyright (C) 2018, Red Hat, Inc.8 * Copyright (C) 2020, Google, Inc.9 */10 11#include <stdio.h>12#include <stdlib.h>13#include <time.h>14#include <pthread.h>15#include <linux/bitmap.h>16 17#include "kvm_util.h"18#include "test_util.h"19#include "memstress.h"20#include "guest_modes.h"21#include "ucall_common.h"22 23#ifdef __aarch64__24#include "aarch64/vgic.h"25 26static int gic_fd;27 28static void arch_setup_vm(struct kvm_vm *vm, unsigned int nr_vcpus)29{30 /*31 * The test can still run even if hardware does not support GICv3, as it32 * is only an optimization to reduce guest exits.33 */34 gic_fd = vgic_v3_setup(vm, nr_vcpus, 64);35}36 37static void arch_cleanup_vm(struct kvm_vm *vm)38{39 if (gic_fd > 0)40 close(gic_fd);41}42 43#else /* __aarch64__ */44 45static void arch_setup_vm(struct kvm_vm *vm, unsigned int nr_vcpus)46{47}48 49static void arch_cleanup_vm(struct kvm_vm *vm)50{51}52 53#endif54 55/* How many host loops to run by default (one KVM_GET_DIRTY_LOG for each loop)*/56#define TEST_HOST_LOOP_N 2UL57 58static int nr_vcpus = 1;59static uint64_t guest_percpu_mem_size = DEFAULT_PER_VCPU_MEM_SIZE;60static bool run_vcpus_while_disabling_dirty_logging;61 62/* Host variables */63static u64 dirty_log_manual_caps;64static bool host_quit;65static int iteration;66static int vcpu_last_completed_iteration[KVM_MAX_VCPUS];67 68static void vcpu_worker(struct memstress_vcpu_args *vcpu_args)69{70 struct kvm_vcpu *vcpu = vcpu_args->vcpu;71 int vcpu_idx = vcpu_args->vcpu_idx;72 uint64_t pages_count = 0;73 struct kvm_run *run;74 struct timespec start;75 struct timespec ts_diff;76 struct timespec total = (struct timespec){0};77 struct timespec avg;78 int ret;79 80 run = vcpu->run;81 82 while (!READ_ONCE(host_quit)) {83 int current_iteration = READ_ONCE(iteration);84 85 clock_gettime(CLOCK_MONOTONIC, &start);86 ret = _vcpu_run(vcpu);87 ts_diff = timespec_elapsed(start);88 89 TEST_ASSERT(ret == 0, "vcpu_run failed: %d", ret);90 TEST_ASSERT(get_ucall(vcpu, NULL) == UCALL_SYNC,91 "Invalid guest sync status: exit_reason=%s",92 exit_reason_str(run->exit_reason));93 94 pr_debug("Got sync event from vCPU %d\n", vcpu_idx);95 vcpu_last_completed_iteration[vcpu_idx] = current_iteration;96 pr_debug("vCPU %d updated last completed iteration to %d\n",97 vcpu_idx, vcpu_last_completed_iteration[vcpu_idx]);98 99 if (current_iteration) {100 pages_count += vcpu_args->pages;101 total = timespec_add(total, ts_diff);102 pr_debug("vCPU %d iteration %d dirty memory time: %ld.%.9lds\n",103 vcpu_idx, current_iteration, ts_diff.tv_sec,104 ts_diff.tv_nsec);105 } else {106 pr_debug("vCPU %d iteration %d populate memory time: %ld.%.9lds\n",107 vcpu_idx, current_iteration, ts_diff.tv_sec,108 ts_diff.tv_nsec);109 }110 111 /*112 * Keep running the guest while dirty logging is being disabled113 * (iteration is negative) so that vCPUs are accessing memory114 * for the entire duration of zapping collapsible SPTEs.115 */116 while (current_iteration == READ_ONCE(iteration) &&117 READ_ONCE(iteration) >= 0 && !READ_ONCE(host_quit)) {}118 }119 120 avg = timespec_div(total, vcpu_last_completed_iteration[vcpu_idx]);121 pr_debug("\nvCPU %d dirtied 0x%lx pages over %d iterations in %ld.%.9lds. (Avg %ld.%.9lds/iteration)\n",122 vcpu_idx, pages_count, vcpu_last_completed_iteration[vcpu_idx],123 total.tv_sec, total.tv_nsec, avg.tv_sec, avg.tv_nsec);124}125 126struct test_params {127 unsigned long iterations;128 uint64_t phys_offset;129 bool partition_vcpu_memory_access;130 enum vm_mem_backing_src_type backing_src;131 int slots;132 uint32_t write_percent;133 bool random_access;134};135 136static void run_test(enum vm_guest_mode mode, void *arg)137{138 struct test_params *p = arg;139 struct kvm_vm *vm;140 unsigned long **bitmaps;141 uint64_t guest_num_pages;142 uint64_t host_num_pages;143 uint64_t pages_per_slot;144 struct timespec start;145 struct timespec ts_diff;146 struct timespec get_dirty_log_total = (struct timespec){0};147 struct timespec vcpu_dirty_total = (struct timespec){0};148 struct timespec avg;149 struct timespec clear_dirty_log_total = (struct timespec){0};150 int i;151 152 vm = memstress_create_vm(mode, nr_vcpus, guest_percpu_mem_size,153 p->slots, p->backing_src,154 p->partition_vcpu_memory_access);155 156 memstress_set_write_percent(vm, p->write_percent);157 158 guest_num_pages = (nr_vcpus * guest_percpu_mem_size) >> vm->page_shift;159 guest_num_pages = vm_adjust_num_guest_pages(mode, guest_num_pages);160 host_num_pages = vm_num_host_pages(mode, guest_num_pages);161 pages_per_slot = host_num_pages / p->slots;162 163 bitmaps = memstress_alloc_bitmaps(p->slots, pages_per_slot);164 165 if (dirty_log_manual_caps)166 vm_enable_cap(vm, KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2,167 dirty_log_manual_caps);168 169 arch_setup_vm(vm, nr_vcpus);170 171 /* Start the iterations */172 iteration = 0;173 host_quit = false;174 175 clock_gettime(CLOCK_MONOTONIC, &start);176 for (i = 0; i < nr_vcpus; i++)177 vcpu_last_completed_iteration[i] = -1;178 179 /*180 * Use 100% writes during the population phase to ensure all181 * memory is actually populated and not just mapped to the zero182 * page. The prevents expensive copy-on-write faults from183 * occurring during the dirty memory iterations below, which184 * would pollute the performance results.185 */186 memstress_set_write_percent(vm, 100);187 memstress_set_random_access(vm, false);188 memstress_start_vcpu_threads(nr_vcpus, vcpu_worker);189 190 /* Allow the vCPUs to populate memory */191 pr_debug("Starting iteration %d - Populating\n", iteration);192 for (i = 0; i < nr_vcpus; i++) {193 while (READ_ONCE(vcpu_last_completed_iteration[i]) !=194 iteration)195 ;196 }197 198 ts_diff = timespec_elapsed(start);199 pr_info("Populate memory time: %ld.%.9lds\n",200 ts_diff.tv_sec, ts_diff.tv_nsec);201 202 /* Enable dirty logging */203 clock_gettime(CLOCK_MONOTONIC, &start);204 memstress_enable_dirty_logging(vm, p->slots);205 ts_diff = timespec_elapsed(start);206 pr_info("Enabling dirty logging time: %ld.%.9lds\n\n",207 ts_diff.tv_sec, ts_diff.tv_nsec);208 209 memstress_set_write_percent(vm, p->write_percent);210 memstress_set_random_access(vm, p->random_access);211 212 while (iteration < p->iterations) {213 /*214 * Incrementing the iteration number will start the vCPUs215 * dirtying memory again.216 */217 clock_gettime(CLOCK_MONOTONIC, &start);218 iteration++;219 220 pr_debug("Starting iteration %d\n", iteration);221 for (i = 0; i < nr_vcpus; i++) {222 while (READ_ONCE(vcpu_last_completed_iteration[i])223 != iteration)224 ;225 }226 227 ts_diff = timespec_elapsed(start);228 vcpu_dirty_total = timespec_add(vcpu_dirty_total, ts_diff);229 pr_info("Iteration %d dirty memory time: %ld.%.9lds\n",230 iteration, ts_diff.tv_sec, ts_diff.tv_nsec);231 232 clock_gettime(CLOCK_MONOTONIC, &start);233 memstress_get_dirty_log(vm, bitmaps, p->slots);234 ts_diff = timespec_elapsed(start);235 get_dirty_log_total = timespec_add(get_dirty_log_total,236 ts_diff);237 pr_info("Iteration %d get dirty log time: %ld.%.9lds\n",238 iteration, ts_diff.tv_sec, ts_diff.tv_nsec);239 240 if (dirty_log_manual_caps) {241 clock_gettime(CLOCK_MONOTONIC, &start);242 memstress_clear_dirty_log(vm, bitmaps, p->slots,243 pages_per_slot);244 ts_diff = timespec_elapsed(start);245 clear_dirty_log_total = timespec_add(clear_dirty_log_total,246 ts_diff);247 pr_info("Iteration %d clear dirty log time: %ld.%.9lds\n",248 iteration, ts_diff.tv_sec, ts_diff.tv_nsec);249 }250 }251 252 /*253 * Run vCPUs while dirty logging is being disabled to stress disabling254 * in terms of both performance and correctness. Opt-in via command255 * line as this significantly increases time to disable dirty logging.256 */257 if (run_vcpus_while_disabling_dirty_logging)258 WRITE_ONCE(iteration, -1);259 260 /* Disable dirty logging */261 clock_gettime(CLOCK_MONOTONIC, &start);262 memstress_disable_dirty_logging(vm, p->slots);263 ts_diff = timespec_elapsed(start);264 pr_info("Disabling dirty logging time: %ld.%.9lds\n",265 ts_diff.tv_sec, ts_diff.tv_nsec);266 267 /*268 * Tell the vCPU threads to quit. No need to manually check that vCPUs269 * have stopped running after disabling dirty logging, the join will270 * wait for them to exit.271 */272 host_quit = true;273 memstress_join_vcpu_threads(nr_vcpus);274 275 avg = timespec_div(get_dirty_log_total, p->iterations);276 pr_info("Get dirty log over %lu iterations took %ld.%.9lds. (Avg %ld.%.9lds/iteration)\n",277 p->iterations, get_dirty_log_total.tv_sec,278 get_dirty_log_total.tv_nsec, avg.tv_sec, avg.tv_nsec);279 280 if (dirty_log_manual_caps) {281 avg = timespec_div(clear_dirty_log_total, p->iterations);282 pr_info("Clear dirty log over %lu iterations took %ld.%.9lds. (Avg %ld.%.9lds/iteration)\n",283 p->iterations, clear_dirty_log_total.tv_sec,284 clear_dirty_log_total.tv_nsec, avg.tv_sec, avg.tv_nsec);285 }286 287 memstress_free_bitmaps(bitmaps, p->slots);288 arch_cleanup_vm(vm);289 memstress_destroy_vm(vm);290}291 292static void help(char *name)293{294 puts("");295 printf("usage: %s [-h] [-a] [-i iterations] [-p offset] [-g] "296 "[-m mode] [-n] [-b vcpu bytes] [-v vcpus] [-o] [-r random seed ] [-s mem type]"297 "[-x memslots] [-w percentage] [-c physical cpus to run test on]\n", name);298 puts("");299 printf(" -a: access memory randomly rather than in order.\n");300 printf(" -i: specify iteration counts (default: %"PRIu64")\n",301 TEST_HOST_LOOP_N);302 printf(" -g: Do not enable KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2. This\n"303 " makes KVM_GET_DIRTY_LOG clear the dirty log (i.e.\n"304 " KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE is not enabled)\n"305 " and writes will be tracked as soon as dirty logging is\n"306 " enabled on the memslot (i.e. KVM_DIRTY_LOG_INITIALLY_SET\n"307 " is not enabled).\n");308 printf(" -p: specify guest physical test memory offset\n"309 " Warning: a low offset can conflict with the loaded test code.\n");310 guest_modes_help();311 printf(" -n: Run the vCPUs in nested mode (L2)\n");312 printf(" -e: Run vCPUs while dirty logging is being disabled. This\n"313 " can significantly increase runtime, especially if there\n"314 " isn't a dedicated pCPU for the main thread.\n");315 printf(" -b: specify the size of the memory region which should be\n"316 " dirtied by each vCPU. e.g. 10M or 3G.\n"317 " (default: 1G)\n");318 printf(" -v: specify the number of vCPUs to run.\n");319 printf(" -o: Overlap guest memory accesses instead of partitioning\n"320 " them into a separate region of memory for each vCPU.\n");321 printf(" -r: specify the starting random seed.\n");322 backing_src_help("-s");323 printf(" -x: Split the memory region into this number of memslots.\n"324 " (default: 1)\n");325 printf(" -w: specify the percentage of pages which should be written to\n"326 " as an integer from 0-100 inclusive. This is probabilistic,\n"327 " so -w X means each page has an X%% chance of writing\n"328 " and a (100-X)%% chance of reading.\n"329 " (default: 100 i.e. all pages are written to.)\n");330 kvm_print_vcpu_pinning_help();331 puts("");332 exit(0);333}334 335int main(int argc, char *argv[])336{337 int max_vcpus = kvm_check_cap(KVM_CAP_MAX_VCPUS);338 const char *pcpu_list = NULL;339 struct test_params p = {340 .iterations = TEST_HOST_LOOP_N,341 .partition_vcpu_memory_access = true,342 .backing_src = DEFAULT_VM_MEM_SRC,343 .slots = 1,344 .write_percent = 100,345 };346 int opt;347 348 /* Override the seed to be deterministic by default. */349 guest_random_seed = 1;350 351 dirty_log_manual_caps =352 kvm_check_cap(KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2);353 dirty_log_manual_caps &= (KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE |354 KVM_DIRTY_LOG_INITIALLY_SET);355 356 guest_modes_append_default();357 358 while ((opt = getopt(argc, argv, "ab:c:eghi:m:nop:r:s:v:x:w:")) != -1) {359 switch (opt) {360 case 'a':361 p.random_access = true;362 break;363 case 'b':364 guest_percpu_mem_size = parse_size(optarg);365 break;366 case 'c':367 pcpu_list = optarg;368 break;369 case 'e':370 /* 'e' is for evil. */371 run_vcpus_while_disabling_dirty_logging = true;372 break;373 case 'g':374 dirty_log_manual_caps = 0;375 break;376 case 'h':377 help(argv[0]);378 break;379 case 'i':380 p.iterations = atoi_positive("Number of iterations", optarg);381 break;382 case 'm':383 guest_modes_cmdline(optarg);384 break;385 case 'n':386 memstress_args.nested = true;387 break;388 case 'o':389 p.partition_vcpu_memory_access = false;390 break;391 case 'p':392 p.phys_offset = strtoull(optarg, NULL, 0);393 break;394 case 'r':395 guest_random_seed = atoi_positive("Random seed", optarg);396 break;397 case 's':398 p.backing_src = parse_backing_src_type(optarg);399 break;400 case 'v':401 nr_vcpus = atoi_positive("Number of vCPUs", optarg);402 TEST_ASSERT(nr_vcpus <= max_vcpus,403 "Invalid number of vcpus, must be between 1 and %d", max_vcpus);404 break;405 case 'w':406 p.write_percent = atoi_non_negative("Write percentage", optarg);407 TEST_ASSERT(p.write_percent <= 100,408 "Write percentage must be between 0 and 100");409 break;410 case 'x':411 p.slots = atoi_positive("Number of slots", optarg);412 break;413 default:414 help(argv[0]);415 break;416 }417 }418 419 if (pcpu_list) {420 kvm_parse_vcpu_pinning(pcpu_list, memstress_args.vcpu_to_pcpu,421 nr_vcpus);422 memstress_args.pin_vcpus = true;423 }424 425 TEST_ASSERT(p.iterations >= 2, "The test should have at least two iterations");426 427 pr_info("Test iterations: %"PRIu64"\n", p.iterations);428 429 for_each_guest_mode(run_test, &p);430 431 return 0;432}433