tools/testing/selftests/kvm/dirty_log_perf_test.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * KVM dirty page logging performance test
   4  *
   5  * Based on dirty_log_test.c
   6  *
   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 "perf_test_util.h"
  20 #include "guest_modes.h"
  21
  22 /* How many host loops to run by default (one KVM_GET_DIRTY_LOG for each loop)*/
  23 #define TEST_HOST_LOOP_N                2UL
  24
  25 static int nr_vcpus = 1;
  26 static uint64_t guest_percpu_mem_size = DEFAULT_PER_VCPU_MEM_SIZE;
  27
  28 /* Host variables */
  29 static u64 dirty_log_manual_caps;
  30 static bool host_quit;
  31 static int iteration;
  32 static int vcpu_last_completed_iteration[KVM_MAX_VCPUS];
  33
  34 static void *vcpu_worker(void *data)
  35 {
  36         int ret;
  37         struct kvm_vm *vm = perf_test_args.vm;
  38         uint64_t pages_count = 0;
  39         struct kvm_run *run;
  40         struct timespec start;
  41         struct timespec ts_diff;
  42         struct timespec total = (struct timespec){0};
  43         struct timespec avg;
  44         struct perf_test_vcpu_args *vcpu_args = (struct perf_test_vcpu_args *)data;
  45         int vcpu_id = vcpu_args->vcpu_id;
  46
  47         run = vcpu_state(vm, vcpu_id);
  48
  49         while (!READ_ONCE(host_quit)) {
  50                 int current_iteration = READ_ONCE(iteration);
  51
  52                 clock_gettime(CLOCK_MONOTONIC, &start);
  53                 ret = _vcpu_run(vm, vcpu_id);
  54                 ts_diff = timespec_elapsed(start);
  55
  56                 TEST_ASSERT(ret == 0, "vcpu_run failed: %d\n", ret);
  57                 TEST_ASSERT(get_ucall(vm, vcpu_id, NULL) == UCALL_SYNC,
  58                             "Invalid guest sync status: exit_reason=%s\n",
  59                             exit_reason_str(run->exit_reason));
  60
  61                 pr_debug("Got sync event from vCPU %d\n", vcpu_id);
  62                 vcpu_last_completed_iteration[vcpu_id] = current_iteration;
  63                 pr_debug("vCPU %d updated last completed iteration to %d\n",
  64                          vcpu_id, vcpu_last_completed_iteration[vcpu_id]);
  65
  66                 if (current_iteration) {
  67                         pages_count += vcpu_args->pages;
  68                         total = timespec_add(total, ts_diff);
  69                         pr_debug("vCPU %d iteration %d dirty memory time: %ld.%.9lds\n",
  70                                 vcpu_id, current_iteration, ts_diff.tv_sec,
  71                                 ts_diff.tv_nsec);
  72                 } else {
  73                         pr_debug("vCPU %d iteration %d populate memory time: %ld.%.9lds\n",
  74                                 vcpu_id, current_iteration, ts_diff.tv_sec,
  75                                 ts_diff.tv_nsec);
  76                 }
  77
  78                 while (current_iteration == READ_ONCE(iteration) &&
  79                        !READ_ONCE(host_quit)) {}
  80         }
  81
  82         avg = timespec_div(total, vcpu_last_completed_iteration[vcpu_id]);
  83         pr_debug("\nvCPU %d dirtied 0x%lx pages over %d iterations in %ld.%.9lds. (Avg %ld.%.9lds/iteration)\n",
  84                 vcpu_id, pages_count, vcpu_last_completed_iteration[vcpu_id],
  85                 total.tv_sec, total.tv_nsec, avg.tv_sec, avg.tv_nsec);
  86
  87         return NULL;
  88 }
  89
  90 struct test_params {
  91         unsigned long iterations;
  92         uint64_t phys_offset;
  93         int wr_fract;
  94         bool partition_vcpu_memory_access;
  95         enum vm_mem_backing_src_type backing_src;
  96         int slots;
  97 };
  98
  99 static void toggle_dirty_logging(struct kvm_vm *vm, int slots, bool enable)
 100 {
 101         int i;
 102
 103         for (i = 0; i < slots; i++) {
 104                 int slot = PERF_TEST_MEM_SLOT_INDEX + i;
 105                 int flags = enable ? KVM_MEM_LOG_DIRTY_PAGES : 0;
 106
 107                 vm_mem_region_set_flags(vm, slot, flags);
 108         }
 109 }
 110
 111 static inline void enable_dirty_logging(struct kvm_vm *vm, int slots)
 112 {
 113         toggle_dirty_logging(vm, slots, true);
 114 }
 115
 116 static inline void disable_dirty_logging(struct kvm_vm *vm, int slots)
 117 {
 118         toggle_dirty_logging(vm, slots, false);
 119 }
 120
 121 static void get_dirty_log(struct kvm_vm *vm, int slots, unsigned long *bitmap,
 122                           uint64_t nr_pages)
 123 {
 124         uint64_t slot_pages = nr_pages / slots;
 125         int i;
 126
 127         for (i = 0; i < slots; i++) {
 128                 int slot = PERF_TEST_MEM_SLOT_INDEX + i;
 129                 unsigned long *slot_bitmap = bitmap + i * slot_pages;
 130
 131                 kvm_vm_get_dirty_log(vm, slot, slot_bitmap);
 132         }
 133 }
 134
 135 static void clear_dirty_log(struct kvm_vm *vm, int slots, unsigned long *bitmap,
 136                             uint64_t nr_pages)
 137 {
 138         uint64_t slot_pages = nr_pages / slots;
 139         int i;
 140
 141         for (i = 0; i < slots; i++) {
 142                 int slot = PERF_TEST_MEM_SLOT_INDEX + i;
 143                 unsigned long *slot_bitmap = bitmap + i * slot_pages;
 144
 145                 kvm_vm_clear_dirty_log(vm, slot, slot_bitmap, 0, slot_pages);
 146         }
 147 }
 148
 149 static void run_test(enum vm_guest_mode mode, void *arg)
 150 {
 151         struct test_params *p = arg;
 152         pthread_t *vcpu_threads;
 153         struct kvm_vm *vm;
 154         unsigned long *bmap;
 155         uint64_t guest_num_pages;
 156         uint64_t host_num_pages;
 157         int vcpu_id;
 158         struct timespec start;
 159         struct timespec ts_diff;
 160         struct timespec get_dirty_log_total = (struct timespec){0};
 161         struct timespec vcpu_dirty_total = (struct timespec){0};
 162         struct timespec avg;
 163         struct kvm_enable_cap cap = {};
 164         struct timespec clear_dirty_log_total = (struct timespec){0};
 165
 166         vm = perf_test_create_vm(mode, nr_vcpus, guest_percpu_mem_size,
 167                                  p->slots, p->backing_src);
 168
 169         perf_test_args.wr_fract = p->wr_fract;
 170
 171         guest_num_pages = (nr_vcpus * guest_percpu_mem_size) >> vm_get_page_shift(vm);
 172         guest_num_pages = vm_adjust_num_guest_pages(mode, guest_num_pages);
 173         host_num_pages = vm_num_host_pages(mode, guest_num_pages);
 174         bmap = bitmap_zalloc(host_num_pages);
 175
 176         if (dirty_log_manual_caps) {
 177                 cap.cap = KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2;
 178                 cap.args[0] = dirty_log_manual_caps;
 179                 vm_enable_cap(vm, &cap);
 180         }
 181
 182         vcpu_threads = malloc(nr_vcpus * sizeof(*vcpu_threads));
 183         TEST_ASSERT(vcpu_threads, "Memory allocation failed");
 184
 185         perf_test_setup_vcpus(vm, nr_vcpus, guest_percpu_mem_size,
 186                               p->partition_vcpu_memory_access);
 187
 188         sync_global_to_guest(vm, perf_test_args);
 189
 190         /* Start the iterations */
 191         iteration = 0;
 192         host_quit = false;
 193
 194         clock_gettime(CLOCK_MONOTONIC, &start);
 195         for (vcpu_id = 0; vcpu_id < nr_vcpus; vcpu_id++) {
 196                 vcpu_last_completed_iteration[vcpu_id] = -1;
 197
 198                 pthread_create(&vcpu_threads[vcpu_id], NULL, vcpu_worker,
 199                                &perf_test_args.vcpu_args[vcpu_id]);
 200         }
 201
 202         /* Allow the vCPUs to populate memory */
 203         pr_debug("Starting iteration %d - Populating\n", iteration);
 204         for (vcpu_id = 0; vcpu_id < nr_vcpus; vcpu_id++) {
 205                 while (READ_ONCE(vcpu_last_completed_iteration[vcpu_id]) !=
 206                        iteration)
 207                         ;
 208         }
 209
 210         ts_diff = timespec_elapsed(start);
 211         pr_info("Populate memory time: %ld.%.9lds\n",
 212                 ts_diff.tv_sec, ts_diff.tv_nsec);
 213
 214         /* Enable dirty logging */
 215         clock_gettime(CLOCK_MONOTONIC, &start);
 216         enable_dirty_logging(vm, p->slots);
 217         ts_diff = timespec_elapsed(start);
 218         pr_info("Enabling dirty logging time: %ld.%.9lds\n\n",
 219                 ts_diff.tv_sec, ts_diff.tv_nsec);
 220
 221         while (iteration < p->iterations) {
 222                 /*
 223                  * Incrementing the iteration number will start the vCPUs
 224                  * dirtying memory again.
 225                  */
 226                 clock_gettime(CLOCK_MONOTONIC, &start);
 227                 iteration++;
 228
 229                 pr_debug("Starting iteration %d\n", iteration);
 230                 for (vcpu_id = 0; vcpu_id < nr_vcpus; vcpu_id++) {
 231                         while (READ_ONCE(vcpu_last_completed_iteration[vcpu_id])
 232                                != iteration)
 233                                 ;
 234                 }
 235
 236                 ts_diff = timespec_elapsed(start);
 237                 vcpu_dirty_total = timespec_add(vcpu_dirty_total, ts_diff);
 238                 pr_info("Iteration %d dirty memory time: %ld.%.9lds\n",
 239                         iteration, ts_diff.tv_sec, ts_diff.tv_nsec);
 240
 241                 clock_gettime(CLOCK_MONOTONIC, &start);
 242                 get_dirty_log(vm, p->slots, bmap, host_num_pages);
 243                 ts_diff = timespec_elapsed(start);
 244                 get_dirty_log_total = timespec_add(get_dirty_log_total,
 245                                                    ts_diff);
 246                 pr_info("Iteration %d get dirty log time: %ld.%.9lds\n",
 247                         iteration, ts_diff.tv_sec, ts_diff.tv_nsec);
 248
 249                 if (dirty_log_manual_caps) {
 250                         clock_gettime(CLOCK_MONOTONIC, &start);
 251                         clear_dirty_log(vm, p->slots, bmap, host_num_pages);
 252                         ts_diff = timespec_elapsed(start);
 253                         clear_dirty_log_total = timespec_add(clear_dirty_log_total,
 254                                                              ts_diff);
 255                         pr_info("Iteration %d clear dirty log time: %ld.%.9lds\n",
 256                                 iteration, ts_diff.tv_sec, ts_diff.tv_nsec);
 257                 }
 258         }
 259
 260         /* Disable dirty logging */
 261         clock_gettime(CLOCK_MONOTONIC, &start);
 262         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         /* Tell the vcpu thread to quit */
 268         host_quit = true;
 269         for (vcpu_id = 0; vcpu_id < nr_vcpus; vcpu_id++)
 270                 pthread_join(vcpu_threads[vcpu_id], NULL);
 271
 272         avg = timespec_div(get_dirty_log_total, p->iterations);
 273         pr_info("Get dirty log over %lu iterations took %ld.%.9lds. (Avg %ld.%.9lds/iteration)\n",
 274                 p->iterations, get_dirty_log_total.tv_sec,
 275                 get_dirty_log_total.tv_nsec, avg.tv_sec, avg.tv_nsec);
 276
 277         if (dirty_log_manual_caps) {
 278                 avg = timespec_div(clear_dirty_log_total, p->iterations);
 279                 pr_info("Clear dirty log over %lu iterations took %ld.%.9lds. (Avg %ld.%.9lds/iteration)\n",
 280                         p->iterations, clear_dirty_log_total.tv_sec,
 281                         clear_dirty_log_total.tv_nsec, avg.tv_sec, avg.tv_nsec);
 282         }
 283
 284         free(bmap);
 285         free(vcpu_threads);
 286         perf_test_destroy_vm(vm);
 287 }
 288
 289 static void help(char *name)
 290 {
 291         puts("");
 292         printf("usage: %s [-h] [-i iterations] [-p offset] "
 293                "[-m mode] [-b vcpu bytes] [-v vcpus] [-o] [-s mem type]"
 294                "[-x memslots]\n", name);
 295         puts("");
 296         printf(" -i: specify iteration counts (default: %"PRIu64")\n",
 297                TEST_HOST_LOOP_N);
 298         printf(" -p: specify guest physical test memory offset\n"
 299                "     Warning: a low offset can conflict with the loaded test code.\n");
 300         guest_modes_help();
 301         printf(" -b: specify the size of the memory region which should be\n"
 302                "     dirtied by each vCPU. e.g. 10M or 3G.\n"
 303                "     (default: 1G)\n");
 304         printf(" -f: specify the fraction of pages which should be written to\n"
 305                "     as opposed to simply read, in the form\n"
 306                "     1/<fraction of pages to write>.\n"
 307                "     (default: 1 i.e. all pages are written to.)\n");
 308         printf(" -v: specify the number of vCPUs to run.\n");
 309         printf(" -o: Overlap guest memory accesses instead of partitioning\n"
 310                "     them into a separate region of memory for each vCPU.\n");
 311         printf(" -s: specify the type of memory that should be used to\n"
 312                "     back the guest data region.\n\n");
 313         printf(" -x: Split the memory region into this number of memslots.\n"
 314                "     (default: 1)");
 315         backing_src_help();
 316         puts("");
 317         exit(0);
 318 }
 319
 320 int main(int argc, char *argv[])
 321 {
 322         int max_vcpus = kvm_check_cap(KVM_CAP_MAX_VCPUS);
 323         struct test_params p = {
 324                 .iterations = TEST_HOST_LOOP_N,
 325                 .wr_fract = 1,
 326                 .partition_vcpu_memory_access = true,
 327                 .backing_src = VM_MEM_SRC_ANONYMOUS,
 328                 .slots = 1,
 329         };
 330         int opt;
 331
 332         dirty_log_manual_caps =
 333                 kvm_check_cap(KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2);
 334         dirty_log_manual_caps &= (KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE |
 335                                   KVM_DIRTY_LOG_INITIALLY_SET);
 336
 337         guest_modes_append_default();
 338
 339         while ((opt = getopt(argc, argv, "hi:p:m:b:f:v:os:x:")) != -1) {
 340                 switch (opt) {
 341                 case 'i':
 342                         p.iterations = atoi(optarg);
 343                         break;
 344                 case 'p':
 345                         p.phys_offset = strtoull(optarg, NULL, 0);
 346                         break;
 347                 case 'm':
 348                         guest_modes_cmdline(optarg);
 349                         break;
 350                 case 'b':
 351                         guest_percpu_mem_size = parse_size(optarg);
 352                         break;
 353                 case 'f':
 354                         p.wr_fract = atoi(optarg);
 355                         TEST_ASSERT(p.wr_fract >= 1,
 356                                     "Write fraction cannot be less than one");
 357                         break;
 358                 case 'v':
 359                         nr_vcpus = atoi(optarg);
 360                         TEST_ASSERT(nr_vcpus > 0 && nr_vcpus <= max_vcpus,
 361                                     "Invalid number of vcpus, must be between 1 and %d", max_vcpus);
 362                         break;
 363                 case 'o':
 364                         p.partition_vcpu_memory_access = false;
 365                         break;
 366                 case 's':
 367                         p.backing_src = parse_backing_src_type(optarg);
 368                         break;
 369                 case 'x':
 370                         p.slots = atoi(optarg);
 371                         break;
 372                 case 'h':
 373                 default:
 374                         help(argv[0]);
 375                         break;
 376                 }
 377         }
 378
 379         TEST_ASSERT(p.iterations >= 2, "The test should have at least two iterations");
 380
 381         pr_info("Test iterations: %"PRIu64"\n", p.iterations);
 382
 383         for_each_guest_mode(run_test, &p);
 384
 385         return 0;
 386 }