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 #ifdef __aarch64__
  23 #include "aarch64/vgic.h"
  24
  25 #define GICD_BASE_GPA                   0x8000000ULL
  26 #define GICR_BASE_GPA                   0x80A0000ULL
  27
  28 static int gic_fd;
  29
  30 static void arch_setup_vm(struct kvm_vm *vm, unsigned int nr_vcpus)
  31 {
  32         /*
  33          * The test can still run even if hardware does not support GICv3, as it
  34          * is only an optimization to reduce guest exits.
  35          */
  36         gic_fd = vgic_v3_setup(vm, nr_vcpus, 64, GICD_BASE_GPA, GICR_BASE_GPA);
  37 }
  38
  39 static void arch_cleanup_vm(struct kvm_vm *vm)
  40 {
  41         if (gic_fd > 0)
  42                 close(gic_fd);
  43 }
  44
  45 #else /* __aarch64__ */
  46
  47 static void arch_setup_vm(struct kvm_vm *vm, unsigned int nr_vcpus)
  48 {
  49 }
  50
  51 static void arch_cleanup_vm(struct kvm_vm *vm)
  52 {
  53 }
  54
  55 #endif
  56
  57 /* How many host loops to run by default (one KVM_GET_DIRTY_LOG for each loop)*/
  58 #define TEST_HOST_LOOP_N                2UL
  59
  60 static int nr_vcpus = 1;
  61 static uint64_t guest_percpu_mem_size = DEFAULT_PER_VCPU_MEM_SIZE;
  62
  63 /* Host variables */
  64 static u64 dirty_log_manual_caps;
  65 static bool host_quit;
  66 static int iteration;
  67 static int vcpu_last_completed_iteration[KVM_MAX_VCPUS];
  68
  69 static void vcpu_worker(struct perf_test_vcpu_args *vcpu_args)
  70 {
  71         int ret;
  72         struct kvm_vm *vm = perf_test_args.vm;
  73         uint64_t pages_count = 0;
  74         struct kvm_run *run;
  75         struct timespec start;
  76         struct timespec ts_diff;
  77         struct timespec total = (struct timespec){0};
  78         struct timespec avg;
  79         int vcpu_id = vcpu_args->vcpu_id;
  80
  81         run = vcpu_state(vm, vcpu_id);
  82
  83         while (!READ_ONCE(host_quit)) {
  84                 int current_iteration = READ_ONCE(iteration);
  85
  86                 clock_gettime(CLOCK_MONOTONIC, &start);
  87                 ret = _vcpu_run(vm, vcpu_id);
  88                 ts_diff = timespec_elapsed(start);
  89
  90                 TEST_ASSERT(ret == 0, "vcpu_run failed: %d\n", ret);
  91                 TEST_ASSERT(get_ucall(vm, vcpu_id, NULL) == UCALL_SYNC,
  92                             "Invalid guest sync status: exit_reason=%s\n",
  93                             exit_reason_str(run->exit_reason));
  94
  95                 pr_debug("Got sync event from vCPU %d\n", vcpu_id);
  96                 vcpu_last_completed_iteration[vcpu_id] = current_iteration;
  97                 pr_debug("vCPU %d updated last completed iteration to %d\n",
  98                          vcpu_id, vcpu_last_completed_iteration[vcpu_id]);
  99
 100                 if (current_iteration) {
 101                         pages_count += vcpu_args->pages;
 102                         total = timespec_add(total, ts_diff);
 103                         pr_debug("vCPU %d iteration %d dirty memory time: %ld.%.9lds\n",
 104                                 vcpu_id, current_iteration, ts_diff.tv_sec,
 105                                 ts_diff.tv_nsec);
 106                 } else {
 107                         pr_debug("vCPU %d iteration %d populate memory time: %ld.%.9lds\n",
 108                                 vcpu_id, current_iteration, ts_diff.tv_sec,
 109                                 ts_diff.tv_nsec);
 110                 }
 111
 112                 while (current_iteration == READ_ONCE(iteration) &&
 113                        !READ_ONCE(host_quit)) {}
 114         }
 115
 116         avg = timespec_div(total, vcpu_last_completed_iteration[vcpu_id]);
 117         pr_debug("\nvCPU %d dirtied 0x%lx pages over %d iterations in %ld.%.9lds. (Avg %ld.%.9lds/iteration)\n",
 118                 vcpu_id, pages_count, vcpu_last_completed_iteration[vcpu_id],
 119                 total.tv_sec, total.tv_nsec, avg.tv_sec, avg.tv_nsec);
 120 }
 121
 122 struct test_params {
 123         unsigned long iterations;
 124         uint64_t phys_offset;
 125         int wr_fract;
 126         bool partition_vcpu_memory_access;
 127         enum vm_mem_backing_src_type backing_src;
 128         int slots;
 129 };
 130
 131 static void toggle_dirty_logging(struct kvm_vm *vm, int slots, bool enable)
 132 {
 133         int i;
 134
 135         for (i = 0; i < slots; i++) {
 136                 int slot = PERF_TEST_MEM_SLOT_INDEX + i;
 137                 int flags = enable ? KVM_MEM_LOG_DIRTY_PAGES : 0;
 138
 139                 vm_mem_region_set_flags(vm, slot, flags);
 140         }
 141 }
 142
 143 static inline void enable_dirty_logging(struct kvm_vm *vm, int slots)
 144 {
 145         toggle_dirty_logging(vm, slots, true);
 146 }
 147
 148 static inline void disable_dirty_logging(struct kvm_vm *vm, int slots)
 149 {
 150         toggle_dirty_logging(vm, slots, false);
 151 }
 152
 153 static void get_dirty_log(struct kvm_vm *vm, unsigned long *bitmaps[], int slots)
 154 {
 155         int i;
 156
 157         for (i = 0; i < slots; i++) {
 158                 int slot = PERF_TEST_MEM_SLOT_INDEX + i;
 159
 160                 kvm_vm_get_dirty_log(vm, slot, bitmaps[i]);
 161         }
 162 }
 163
 164 static void clear_dirty_log(struct kvm_vm *vm, unsigned long *bitmaps[],
 165                             int slots, uint64_t pages_per_slot)
 166 {
 167         int i;
 168
 169         for (i = 0; i < slots; i++) {
 170                 int slot = PERF_TEST_MEM_SLOT_INDEX + i;
 171
 172                 kvm_vm_clear_dirty_log(vm, slot, bitmaps[i], 0, pages_per_slot);
 173         }
 174 }
 175
 176 static unsigned long **alloc_bitmaps(int slots, uint64_t pages_per_slot)
 177 {
 178         unsigned long **bitmaps;
 179         int i;
 180
 181         bitmaps = malloc(slots * sizeof(bitmaps[0]));
 182         TEST_ASSERT(bitmaps, "Failed to allocate bitmaps array.");
 183
 184         for (i = 0; i < slots; i++) {
 185                 bitmaps[i] = bitmap_zalloc(pages_per_slot);
 186                 TEST_ASSERT(bitmaps[i], "Failed to allocate slot bitmap.");
 187         }
 188
 189         return bitmaps;
 190 }
 191
 192 static void free_bitmaps(unsigned long *bitmaps[], int slots)
 193 {
 194         int i;
 195
 196         for (i = 0; i < slots; i++)
 197                 free(bitmaps[i]);
 198
 199         free(bitmaps);
 200 }
 201
 202 static void run_test(enum vm_guest_mode mode, void *arg)
 203 {
 204         struct test_params *p = arg;
 205         struct kvm_vm *vm;
 206         unsigned long **bitmaps;
 207         uint64_t guest_num_pages;
 208         uint64_t host_num_pages;
 209         uint64_t pages_per_slot;
 210         int vcpu_id;
 211         struct timespec start;
 212         struct timespec ts_diff;
 213         struct timespec get_dirty_log_total = (struct timespec){0};
 214         struct timespec vcpu_dirty_total = (struct timespec){0};
 215         struct timespec avg;
 216         struct kvm_enable_cap cap = {};
 217         struct timespec clear_dirty_log_total = (struct timespec){0};
 218
 219         vm = perf_test_create_vm(mode, nr_vcpus, guest_percpu_mem_size,
 220                                  p->slots, p->backing_src,
 221                                  p->partition_vcpu_memory_access);
 222
 223         perf_test_set_wr_fract(vm, p->wr_fract);
 224
 225         guest_num_pages = (nr_vcpus * guest_percpu_mem_size) >> vm_get_page_shift(vm);
 226         guest_num_pages = vm_adjust_num_guest_pages(mode, guest_num_pages);
 227         host_num_pages = vm_num_host_pages(mode, guest_num_pages);
 228         pages_per_slot = host_num_pages / p->slots;
 229
 230         bitmaps = alloc_bitmaps(p->slots, pages_per_slot);
 231
 232         if (dirty_log_manual_caps) {
 233                 cap.cap = KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2;
 234                 cap.args[0] = dirty_log_manual_caps;
 235                 vm_enable_cap(vm, &cap);
 236         }
 237
 238         arch_setup_vm(vm, nr_vcpus);
 239
 240         /* Start the iterations */
 241         iteration = 0;
 242         host_quit = false;
 243
 244         clock_gettime(CLOCK_MONOTONIC, &start);
 245         for (vcpu_id = 0; vcpu_id < nr_vcpus; vcpu_id++)
 246                 vcpu_last_completed_iteration[vcpu_id] = -1;
 247
 248         perf_test_start_vcpu_threads(nr_vcpus, vcpu_worker);
 249
 250         /* Allow the vCPUs to populate memory */
 251         pr_debug("Starting iteration %d - Populating\n", iteration);
 252         for (vcpu_id = 0; vcpu_id < nr_vcpus; vcpu_id++) {
 253                 while (READ_ONCE(vcpu_last_completed_iteration[vcpu_id]) !=
 254                        iteration)
 255                         ;
 256         }
 257
 258         ts_diff = timespec_elapsed(start);
 259         pr_info("Populate memory time: %ld.%.9lds\n",
 260                 ts_diff.tv_sec, ts_diff.tv_nsec);
 261
 262         /* Enable dirty logging */
 263         clock_gettime(CLOCK_MONOTONIC, &start);
 264         enable_dirty_logging(vm, p->slots);
 265         ts_diff = timespec_elapsed(start);
 266         pr_info("Enabling dirty logging time: %ld.%.9lds\n\n",
 267                 ts_diff.tv_sec, ts_diff.tv_nsec);
 268
 269         while (iteration < p->iterations) {
 270                 /*
 271                  * Incrementing the iteration number will start the vCPUs
 272                  * dirtying memory again.
 273                  */
 274                 clock_gettime(CLOCK_MONOTONIC, &start);
 275                 iteration++;
 276
 277                 pr_debug("Starting iteration %d\n", iteration);
 278                 for (vcpu_id = 0; vcpu_id < nr_vcpus; vcpu_id++) {
 279                         while (READ_ONCE(vcpu_last_completed_iteration[vcpu_id])
 280                                != iteration)
 281                                 ;
 282                 }
 283
 284                 ts_diff = timespec_elapsed(start);
 285                 vcpu_dirty_total = timespec_add(vcpu_dirty_total, ts_diff);
 286                 pr_info("Iteration %d dirty memory time: %ld.%.9lds\n",
 287                         iteration, ts_diff.tv_sec, ts_diff.tv_nsec);
 288
 289                 clock_gettime(CLOCK_MONOTONIC, &start);
 290                 get_dirty_log(vm, bitmaps, p->slots);
 291                 ts_diff = timespec_elapsed(start);
 292                 get_dirty_log_total = timespec_add(get_dirty_log_total,
 293                                                    ts_diff);
 294                 pr_info("Iteration %d get dirty log time: %ld.%.9lds\n",
 295                         iteration, ts_diff.tv_sec, ts_diff.tv_nsec);
 296
 297                 if (dirty_log_manual_caps) {
 298                         clock_gettime(CLOCK_MONOTONIC, &start);
 299                         clear_dirty_log(vm, bitmaps, p->slots, pages_per_slot);
 300                         ts_diff = timespec_elapsed(start);
 301                         clear_dirty_log_total = timespec_add(clear_dirty_log_total,
 302                                                              ts_diff);
 303                         pr_info("Iteration %d clear dirty log time: %ld.%.9lds\n",
 304                                 iteration, ts_diff.tv_sec, ts_diff.tv_nsec);
 305                 }
 306         }
 307
 308         /* Disable dirty logging */
 309         clock_gettime(CLOCK_MONOTONIC, &start);
 310         disable_dirty_logging(vm, p->slots);
 311         ts_diff = timespec_elapsed(start);
 312         pr_info("Disabling dirty logging time: %ld.%.9lds\n",
 313                 ts_diff.tv_sec, ts_diff.tv_nsec);
 314
 315         /* Tell the vcpu thread to quit */
 316         host_quit = true;
 317         perf_test_join_vcpu_threads(nr_vcpus);
 318
 319         avg = timespec_div(get_dirty_log_total, p->iterations);
 320         pr_info("Get dirty log over %lu iterations took %ld.%.9lds. (Avg %ld.%.9lds/iteration)\n",
 321                 p->iterations, get_dirty_log_total.tv_sec,
 322                 get_dirty_log_total.tv_nsec, avg.tv_sec, avg.tv_nsec);
 323
 324         if (dirty_log_manual_caps) {
 325                 avg = timespec_div(clear_dirty_log_total, p->iterations);
 326                 pr_info("Clear dirty log over %lu iterations took %ld.%.9lds. (Avg %ld.%.9lds/iteration)\n",
 327                         p->iterations, clear_dirty_log_total.tv_sec,
 328                         clear_dirty_log_total.tv_nsec, avg.tv_sec, avg.tv_nsec);
 329         }
 330
 331         free_bitmaps(bitmaps, p->slots);
 332         arch_cleanup_vm(vm);
 333         perf_test_destroy_vm(vm);
 334 }
 335
 336 static void help(char *name)
 337 {
 338         puts("");
 339         printf("usage: %s [-h] [-i iterations] [-p offset] [-g]"
 340                "[-m mode] [-b vcpu bytes] [-v vcpus] [-o] [-s mem type]"
 341                "[-x memslots]\n", name);
 342         puts("");
 343         printf(" -i: specify iteration counts (default: %"PRIu64")\n",
 344                TEST_HOST_LOOP_N);
 345         printf(" -g: Do not enable KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2. This\n"
 346                "     makes KVM_GET_DIRTY_LOG clear the dirty log (i.e.\n"
 347                "     KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE is not enabled)\n"
 348                "     and writes will be tracked as soon as dirty logging is\n"
 349                "     enabled on the memslot (i.e. KVM_DIRTY_LOG_INITIALLY_SET\n"
 350                "     is not enabled).\n");
 351         printf(" -p: specify guest physical test memory offset\n"
 352                "     Warning: a low offset can conflict with the loaded test code.\n");
 353         guest_modes_help();
 354         printf(" -b: specify the size of the memory region which should be\n"
 355                "     dirtied by each vCPU. e.g. 10M or 3G.\n"
 356                "     (default: 1G)\n");
 357         printf(" -f: specify the fraction of pages which should be written to\n"
 358                "     as opposed to simply read, in the form\n"
 359                "     1/<fraction of pages to write>.\n"
 360                "     (default: 1 i.e. all pages are written to.)\n");
 361         printf(" -v: specify the number of vCPUs to run.\n");
 362         printf(" -o: Overlap guest memory accesses instead of partitioning\n"
 363                "     them into a separate region of memory for each vCPU.\n");
 364         backing_src_help("-s");
 365         printf(" -x: Split the memory region into this number of memslots.\n"
 366                "     (default: 1)\n");
 367         puts("");
 368         exit(0);
 369 }
 370
 371 int main(int argc, char *argv[])
 372 {
 373         int max_vcpus = kvm_check_cap(KVM_CAP_MAX_VCPUS);
 374         struct test_params p = {
 375                 .iterations = TEST_HOST_LOOP_N,
 376                 .wr_fract = 1,
 377                 .partition_vcpu_memory_access = true,
 378                 .backing_src = DEFAULT_VM_MEM_SRC,
 379                 .slots = 1,
 380         };
 381         int opt;
 382
 383         dirty_log_manual_caps =
 384                 kvm_check_cap(KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2);
 385         dirty_log_manual_caps &= (KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE |
 386                                   KVM_DIRTY_LOG_INITIALLY_SET);
 387
 388         guest_modes_append_default();
 389
 390         while ((opt = getopt(argc, argv, "ghi:p:m:b:f:v:os:x:")) != -1) {
 391                 switch (opt) {
 392                 case 'g':
 393                         dirty_log_manual_caps = 0;
 394                         break;
 395                 case 'i':
 396                         p.iterations = atoi(optarg);
 397                         break;
 398                 case 'p':
 399                         p.phys_offset = strtoull(optarg, NULL, 0);
 400                         break;
 401                 case 'm':
 402                         guest_modes_cmdline(optarg);
 403                         break;
 404                 case 'b':
 405                         guest_percpu_mem_size = parse_size(optarg);
 406                         break;
 407                 case 'f':
 408                         p.wr_fract = atoi(optarg);
 409                         TEST_ASSERT(p.wr_fract >= 1,
 410                                     "Write fraction cannot be less than one");
 411                         break;
 412                 case 'v':
 413                         nr_vcpus = atoi(optarg);
 414                         TEST_ASSERT(nr_vcpus > 0 && nr_vcpus <= max_vcpus,
 415                                     "Invalid number of vcpus, must be between 1 and %d", max_vcpus);
 416                         break;
 417                 case 'o':
 418                         p.partition_vcpu_memory_access = false;
 419                         break;
 420                 case 's':
 421                         p.backing_src = parse_backing_src_type(optarg);
 422                         break;
 423                 case 'x':
 424                         p.slots = atoi(optarg);
 425                         break;
 426                 case 'h':
 427                 default:
 428                         help(argv[0]);
 429                         break;
 430                 }
 431         }
 432
 433         TEST_ASSERT(p.iterations >= 2, "The test should have at least two iterations");
 434
 435         pr_info("Test iterations: %"PRIu64"\n", p.iterations);
 436
 437         for_each_guest_mode(run_test, &p);
 438
 439         return 0;
 440 }