1 // SPDX-License-Identifier: GPL-2.0
3 * KVM dirty page logging performance test
5 * Based on dirty_log_test.c
7 * Copyright (C) 2018, Red Hat, Inc.
8 * Copyright (C) 2020, Google, Inc.
15 #include <linux/bitmap.h>
18 #include "test_util.h"
19 #include "perf_test_util.h"
20 #include "guest_modes.h"
22 /* How many host loops to run by default (one KVM_GET_DIRTY_LOG for each loop)*/
23 #define TEST_HOST_LOOP_N 2UL
25 static int nr_vcpus = 1;
26 static uint64_t guest_percpu_mem_size = DEFAULT_PER_VCPU_MEM_SIZE;
29 static u64 dirty_log_manual_caps;
30 static bool host_quit;
32 static int vcpu_last_completed_iteration[KVM_MAX_VCPUS];
34 static void *vcpu_worker(void *data)
37 struct kvm_vm *vm = perf_test_args.vm;
38 uint64_t pages_count = 0;
40 struct timespec start;
41 struct timespec ts_diff;
42 struct timespec total = (struct timespec){0};
44 struct perf_test_vcpu_args *vcpu_args = (struct perf_test_vcpu_args *)data;
45 int vcpu_id = vcpu_args->vcpu_id;
47 run = vcpu_state(vm, vcpu_id);
49 while (!READ_ONCE(host_quit)) {
50 int current_iteration = READ_ONCE(iteration);
52 clock_gettime(CLOCK_MONOTONIC, &start);
53 ret = _vcpu_run(vm, vcpu_id);
54 ts_diff = timespec_elapsed(start);
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));
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]);
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,
73 pr_debug("vCPU %d iteration %d populate memory time: %ld.%.9lds\n",
74 vcpu_id, current_iteration, ts_diff.tv_sec,
78 while (current_iteration == READ_ONCE(iteration) &&
79 !READ_ONCE(host_quit)) {}
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);
91 unsigned long iterations;
94 bool partition_vcpu_memory_access;
95 enum vm_mem_backing_src_type backing_src;
99 static void toggle_dirty_logging(struct kvm_vm *vm, int slots, bool enable)
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;
107 vm_mem_region_set_flags(vm, slot, flags);
111 static inline void enable_dirty_logging(struct kvm_vm *vm, int slots)
113 toggle_dirty_logging(vm, slots, true);
116 static inline void disable_dirty_logging(struct kvm_vm *vm, int slots)
118 toggle_dirty_logging(vm, slots, false);
121 static void get_dirty_log(struct kvm_vm *vm, int slots, unsigned long *bitmap,
124 uint64_t slot_pages = nr_pages / slots;
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;
131 kvm_vm_get_dirty_log(vm, slot, slot_bitmap);
135 static void clear_dirty_log(struct kvm_vm *vm, int slots, unsigned long *bitmap,
138 uint64_t slot_pages = nr_pages / slots;
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;
145 kvm_vm_clear_dirty_log(vm, slot, slot_bitmap, 0, slot_pages);
149 static void run_test(enum vm_guest_mode mode, void *arg)
151 struct test_params *p = arg;
152 pthread_t *vcpu_threads;
155 uint64_t guest_num_pages;
156 uint64_t host_num_pages;
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};
163 struct kvm_enable_cap cap = {};
164 struct timespec clear_dirty_log_total = (struct timespec){0};
166 vm = perf_test_create_vm(mode, nr_vcpus, guest_percpu_mem_size,
167 p->slots, p->backing_src);
169 perf_test_args.wr_fract = p->wr_fract;
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_alloc(host_num_pages);
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);
182 vcpu_threads = malloc(nr_vcpus * sizeof(*vcpu_threads));
183 TEST_ASSERT(vcpu_threads, "Memory allocation failed");
185 perf_test_setup_vcpus(vm, nr_vcpus, guest_percpu_mem_size,
186 p->partition_vcpu_memory_access);
188 sync_global_to_guest(vm, perf_test_args);
190 /* Start the iterations */
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;
198 pthread_create(&vcpu_threads[vcpu_id], NULL, vcpu_worker,
199 &perf_test_args.vcpu_args[vcpu_id]);
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]) !=
210 ts_diff = timespec_elapsed(start);
211 pr_info("Populate memory time: %ld.%.9lds\n",
212 ts_diff.tv_sec, ts_diff.tv_nsec);
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);
221 while (iteration < p->iterations) {
223 * Incrementing the iteration number will start the vCPUs
224 * dirtying memory again.
226 clock_gettime(CLOCK_MONOTONIC, &start);
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])
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);
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,
246 pr_info("Iteration %d get dirty log time: %ld.%.9lds\n",
247 iteration, ts_diff.tv_sec, ts_diff.tv_nsec);
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,
255 pr_info("Iteration %d clear dirty log time: %ld.%.9lds\n",
256 iteration, ts_diff.tv_sec, ts_diff.tv_nsec);
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);
267 /* Tell the vcpu thread to quit */
269 for (vcpu_id = 0; vcpu_id < nr_vcpus; vcpu_id++)
270 pthread_join(vcpu_threads[vcpu_id], NULL);
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);
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);
286 perf_test_destroy_vm(vm);
289 static void help(char *name)
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);
296 printf(" -i: specify iteration counts (default: %"PRIu64")\n",
298 printf(" -p: specify guest physical test memory offset\n"
299 " Warning: a low offset can conflict with the loaded test code.\n");
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"
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"
320 int main(int argc, char *argv[])
322 int max_vcpus = kvm_check_cap(KVM_CAP_MAX_VCPUS);
323 struct test_params p = {
324 .iterations = TEST_HOST_LOOP_N,
326 .partition_vcpu_memory_access = true,
327 .backing_src = VM_MEM_SRC_ANONYMOUS,
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);
337 guest_modes_append_default();
339 while ((opt = getopt(argc, argv, "hi:p:m:b:f:v:os:x:")) != -1) {
342 p.iterations = atoi(optarg);
345 p.phys_offset = strtoull(optarg, NULL, 0);
348 guest_modes_cmdline(optarg);
351 guest_percpu_mem_size = parse_size(optarg);
354 p.wr_fract = atoi(optarg);
355 TEST_ASSERT(p.wr_fract >= 1,
356 "Write fraction cannot be less than one");
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);
364 p.partition_vcpu_memory_access = false;
367 p.backing_src = parse_backing_src_type(optarg);
370 p.slots = atoi(optarg);
379 TEST_ASSERT(p.iterations >= 2, "The test should have at least two iterations");
381 pr_info("Test iterations: %"PRIu64"\n", p.iterations);
383 for_each_guest_mode(run_test, &p);