// SPDX-License-Identifier: GPL-2.0
/*
* KVM dirty page logging performance test
*
* Based on dirty_log_test.c
*
* 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 "kvm_util.h"
#include "test_util.h"
#include "memstress.h"
#include "guest_modes.h"
#include "ucall_common.h"
#ifdef __aarch64__
#include "aarch64/vgic.h"
static int gic_fd;
static void arch_setup_vm(struct kvm_vm *vm, unsigned int nr_vcpus)
{
/*
* The test can still run even if hardware does not support GICv3, as it
* is only an optimization to reduce guest exits.
*/
gic_fd = vgic_v3_setup(vm, nr_vcpus, 64);
}
static void arch_cleanup_vm(struct kvm_vm *vm)
{
if (gic_fd > 0)
close(gic_fd);
}
#else /* __aarch64__ */
static void arch_setup_vm(struct kvm_vm *vm, unsigned int nr_vcpus)
{
}
static void arch_cleanup_vm(struct kvm_vm *vm)
{
}
#endif
/* 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 uint64_t 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 bool host_quit;
static int iteration;
static int vcpu_last_completed_iteration[KVM_MAX_VCPUS];
static void vcpu_worker(struct memstress_vcpu_args *vcpu_args)
{
struct kvm_vcpu *vcpu = vcpu_args->vcpu;
int vcpu_idx = vcpu_args->vcpu_idx;
uint64_t pages_count = 0;
struct kvm_run *run;
struct timespec start;
struct timespec ts_diff;
struct timespec total = (struct timespec){0};
struct timespec avg;
int ret;
run = vcpu->run;
while (!READ_ONCE(host_quit)) {
int current_iteration = READ_ONCE(iteration);
clock_gettime(CLOCK_MONOTONIC, &start);
ret = _vcpu_run(vcpu);
ts_diff = timespec_elapsed(start);
TEST_ASSERT(ret == 0, "vcpu_run failed: %d", ret);
TEST_ASSERT(get_ucall(vcpu, NULL) == UCALL_SYNC,
"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;
total = timespec_add(total, ts_diff);
pr_debug("vCPU %d iteration %d dirty memory time: %ld.%.9lds\n",
vcpu_idx, current_iteration, ts_diff.tv_sec,
ts_diff.tv_nsec);
} else {
pr_debug("vCPU %d iteration %d populate memory time: %ld.%.9lds\n",
vcpu_idx, current_iteration, ts_diff.tv_sec,
ts_diff.tv_nsec);
}
/*
* Keep running the guest while dirty logging is being disabled
* (iteration is negative) so that vCPUs are accessing memory
* for the entire duration of zapping collapsible SPTEs.
*/
while (current_iteration == READ_ONCE(iteration) &&
READ_ONCE(iteration) >= 0 && !READ_ONCE(host_quit)) {}
}
avg = timespec_div(total, vcpu_last_completed_iteration[vcpu_idx]);
pr_debug("\nvCPU %d dirtied 0x%lx pages over %d iterations in %ld.%.9lds. (Avg %ld.%.9lds/iteration)\n",
vcpu_idx, pages_count, vcpu_last_completed_iteration[vcpu_idx],
total.tv_sec, total.tv_nsec, avg.tv_sec, avg.tv_nsec);
}
struct test_params {
unsigned long iterations;
uint64_t phys_offset;
bool partition_vcpu_memory_access;
enum vm_mem_backing_src_type backing_src;
int slots;
uint32_t write_percent;
bool random_access;
};
static void run_test(enum vm_guest_mode mode, void *arg)
{
struct test_params *p = arg;
struct kvm_vm *vm;
unsigned long **bitmaps;
uint64_t guest_num_pages;
uint64_t host_num_pages;
uint64_t pages_per_slot;
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);
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);
arch_setup_vm(vm, nr_vcpus);
/* Start the iterations */
iteration = 0;
host_quit = false;
clock_gettime(CLOCK_MONOTONIC, &start);
for (i = 0; i < nr_vcpus; i++)
vcpu_last_completed_iteration[i] = -1;
/*
* 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);
memstress_start_vcpu_threads(nr_vcpus, vcpu_worker);
/* Allow the vCPUs to populate memory */
pr_debug("Starting iteration %d - Populating\n", iteration);
for (i = 0; i < nr_vcpus; i++) {
while (READ_ONCE(vcpu_last_completed_iteration[i]) !=
iteration)
;
}
ts_diff = timespec_elapsed(start);
pr_info("Populate memory time: %ld.%.9lds\n",
ts_diff.tv_sec, ts_diff.tv_nsec);
/* Enable dirty logging */
clock_gettime(CLOCK_MONOTONIC, &start);
memstress_enable_dirty_logging(vm, p->slots);
ts_diff = timespec_elapsed(start);
pr_info("Enabling dirty logging time: %ld.%.9lds\n\n",
ts_diff.tv_sec, ts_diff.tv_nsec);
memstress_set_write_percent(vm, p->write_percent);
memstress_set_random_access(vm, p->random_access);
while (iteration < p->iterations) {
/*
* Incrementing the iteration number will start the vCPUs
* dirtying memory again.
*/
clock_gettime(CLOCK_MONOTONIC, &start);
iteration++;
pr_debug("Starting iteration %d\n", iteration);
for (i = 0; i < nr_vcpus; i++) {
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);
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);
memstress_clear_dirty_log(vm, bitmaps, p->slots,
pages_per_slot);
ts_diff = timespec_elapsed(start);
clear_dirty_log_total = timespec_add(clear_dirty_log_total,
ts_diff);
pr_info("Iteration %d clear dirty log time: %ld.%.9lds\n",
iteration, ts_diff.tv_sec, ts_diff.tv_nsec);
}
}
/*
* Run vCPUs while dirty logging is being disabled to stress disabling
* in terms of both performance and correctness. Opt-in via command
* line as this significantly increases time to disable dirty logging.
*/
if (run_vcpus_while_disabling_dirty_logging)
WRITE_ONCE(iteration, -1);
/* Disable dirty logging */
clock_gettime(CLOCK_MONOTONIC, &start);
memstress_disable_dirty_logging(vm, p->slots);
ts_diff = timespec_elapsed(start);
pr_info("Disabling dirty logging time: %ld.%.9lds\n",
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_log_manual_caps) {
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);
arch_cleanup_vm(vm);
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(" -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");
printf(" -e: Run vCPUs while dirty logging is being disabled. This\n"
" can significantly increase runtime, especially if there\n"
" isn't a dedicated pCPU for the main thread.\n");
printf(" -b: specify the size of the memory region which should be\n"
" dirtied by each vCPU. e.g. 10M or 3G.\n"
" (default: 1G)\n");
printf(" -v: specify the number of vCPUs to run.\n");
printf(" -o: Overlap guest memory accesses instead of partitioning\n"
" them into a separate region of memory for each vCPU.\n");
printf(" -r: specify the starting random seed.\n");
backing_src_help("-s");
printf(" -x: Split the memory region into this number of memslots.\n"
" (default: 1)\n");
printf(" -w: specify the percentage of pages which should be written to\n"
" as an integer from 0-100 inclusive. This is probabilistic,\n"
" so -w X means each page has an X%% chance of writing\n"
" and a (100-X)%% chance of reading.\n"
" (default: 100 i.e. all pages are written to.)\n");
kvm_print_vcpu_pinning_help();
puts("");
exit(0);
}
int main(int argc, char *argv[])
{
int max_vcpus = kvm_check_cap(KVM_CAP_MAX_VCPUS);
const char *pcpu_list = NULL;
struct test_params p = {
.iterations = TEST_HOST_LOOP_N,
.partition_vcpu_memory_access = true,
.backing_src = DEFAULT_VM_MEM_SRC,
.slots = 1,
.write_percent = 100,
};
int opt;
/* 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) {
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 '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;
case 'i':
p.iterations = atoi_positive("Number of iterations", optarg);
break;
case 'm':
guest_modes_cmdline(optarg);
break;
case 'n':
memstress_args.nested = true;
break;
case 'o':
p.partition_vcpu_memory_access = false;
break;
case 'p':
p.phys_offset = strtoull(optarg, NULL, 0);
break;
case 'r':
guest_random_seed = atoi_positive("Random seed", optarg);
break;
case 's':
p.backing_src = parse_backing_src_type(optarg);
break;
case 'v':
nr_vcpus = atoi_positive("Number of vCPUs", optarg);
TEST_ASSERT(nr_vcpus <= max_vcpus,
"Invalid number of vcpus, must be between 1 and %d", max_vcpus);
break;
case 'w':
p.write_percent = atoi_non_negative("Write percentage", optarg);
TEST_ASSERT(p.write_percent <= 100,
"Write percentage must be between 0 and 100");
break;
case 'x':
p.slots = atoi_positive("Number of slots", optarg);
break;
default:
help(argv[0]);
break;
}
}
if (pcpu_list) {
kvm_parse_vcpu_pinning(pcpu_list, memstress_args.vcpu_to_pcpu,
nr_vcpus);
memstress_args.pin_vcpus = true;
}
TEST_ASSERT(p.iterations >= 2, "The test should have at least two iterations");
pr_info("Test iterations: %"PRIu64"\n", p.iterations);
for_each_guest_mode(run_test, &p);
return 0;
}
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