blob: aace12a787646231acce0428d0d8fc5c941a98e2 [file] [log] [blame]
/*
* Dirtyrate implement code
*
* Copyright (c) 2020 HUAWEI TECHNOLOGIES CO.,LTD.
*
* Authors:
* Chuan Zheng <zhengchuan@huawei.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include <zlib.h>
#include "qapi/error.h"
#include "cpu.h"
#include "exec/ramblock.h"
#include "exec/ram_addr.h"
#include "qemu/rcu_queue.h"
#include "qemu/main-loop.h"
#include "qapi/qapi-commands-migration.h"
#include "ram.h"
#include "trace.h"
#include "dirtyrate.h"
#include "monitor/hmp.h"
#include "monitor/monitor.h"
#include "qapi/qmp/qdict.h"
#include "sysemu/kvm.h"
#include "sysemu/runstate.h"
#include "exec/memory.h"
/*
* total_dirty_pages is procted by BQL and is used
* to stat dirty pages during the period of two
* memory_global_dirty_log_sync
*/
uint64_t total_dirty_pages;
typedef struct DirtyPageRecord {
uint64_t start_pages;
uint64_t end_pages;
} DirtyPageRecord;
static int CalculatingState = DIRTY_RATE_STATUS_UNSTARTED;
static struct DirtyRateStat DirtyStat;
static DirtyRateMeasureMode dirtyrate_mode =
DIRTY_RATE_MEASURE_MODE_PAGE_SAMPLING;
static int64_t set_sample_page_period(int64_t msec, int64_t initial_time)
{
int64_t current_time;
current_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
if ((current_time - initial_time) >= msec) {
msec = current_time - initial_time;
} else {
g_usleep((msec + initial_time - current_time) * 1000);
}
return msec;
}
static bool is_sample_period_valid(int64_t sec)
{
if (sec < MIN_FETCH_DIRTYRATE_TIME_SEC ||
sec > MAX_FETCH_DIRTYRATE_TIME_SEC) {
return false;
}
return true;
}
static bool is_sample_pages_valid(int64_t pages)
{
return pages >= MIN_SAMPLE_PAGE_COUNT &&
pages <= MAX_SAMPLE_PAGE_COUNT;
}
static int dirtyrate_set_state(int *state, int old_state, int new_state)
{
assert(new_state < DIRTY_RATE_STATUS__MAX);
trace_dirtyrate_set_state(DirtyRateStatus_str(new_state));
if (qatomic_cmpxchg(state, old_state, new_state) == old_state) {
return 0;
} else {
return -1;
}
}
static struct DirtyRateInfo *query_dirty_rate_info(void)
{
int i;
int64_t dirty_rate = DirtyStat.dirty_rate;
struct DirtyRateInfo *info = g_new0(DirtyRateInfo, 1);
DirtyRateVcpuList *head = NULL, **tail = &head;
info->status = CalculatingState;
info->start_time = DirtyStat.start_time;
info->calc_time = DirtyStat.calc_time;
info->sample_pages = DirtyStat.sample_pages;
info->mode = dirtyrate_mode;
if (qatomic_read(&CalculatingState) == DIRTY_RATE_STATUS_MEASURED) {
info->has_dirty_rate = true;
info->dirty_rate = dirty_rate;
if (dirtyrate_mode == DIRTY_RATE_MEASURE_MODE_DIRTY_RING) {
/*
* set sample_pages with 0 to indicate page sampling
* isn't enabled
**/
info->sample_pages = 0;
info->has_vcpu_dirty_rate = true;
for (i = 0; i < DirtyStat.dirty_ring.nvcpu; i++) {
DirtyRateVcpu *rate = g_new0(DirtyRateVcpu, 1);
rate->id = DirtyStat.dirty_ring.rates[i].id;
rate->dirty_rate = DirtyStat.dirty_ring.rates[i].dirty_rate;
QAPI_LIST_APPEND(tail, rate);
}
info->vcpu_dirty_rate = head;
}
if (dirtyrate_mode == DIRTY_RATE_MEASURE_MODE_DIRTY_BITMAP) {
info->sample_pages = 0;
}
}
trace_query_dirty_rate_info(DirtyRateStatus_str(CalculatingState));
return info;
}
static void init_dirtyrate_stat(int64_t start_time,
struct DirtyRateConfig config)
{
DirtyStat.dirty_rate = -1;
DirtyStat.start_time = start_time;
DirtyStat.calc_time = config.sample_period_seconds;
DirtyStat.sample_pages = config.sample_pages_per_gigabytes;
switch (config.mode) {
case DIRTY_RATE_MEASURE_MODE_PAGE_SAMPLING:
DirtyStat.page_sampling.total_dirty_samples = 0;
DirtyStat.page_sampling.total_sample_count = 0;
DirtyStat.page_sampling.total_block_mem_MB = 0;
break;
case DIRTY_RATE_MEASURE_MODE_DIRTY_RING:
DirtyStat.dirty_ring.nvcpu = -1;
DirtyStat.dirty_ring.rates = NULL;
break;
default:
break;
}
}
static void cleanup_dirtyrate_stat(struct DirtyRateConfig config)
{
/* last calc-dirty-rate qmp use dirty ring mode */
if (dirtyrate_mode == DIRTY_RATE_MEASURE_MODE_DIRTY_RING) {
free(DirtyStat.dirty_ring.rates);
DirtyStat.dirty_ring.rates = NULL;
}
}
static void update_dirtyrate_stat(struct RamblockDirtyInfo *info)
{
DirtyStat.page_sampling.total_dirty_samples += info->sample_dirty_count;
DirtyStat.page_sampling.total_sample_count += info->sample_pages_count;
/* size of total pages in MB */
DirtyStat.page_sampling.total_block_mem_MB += (info->ramblock_pages *
TARGET_PAGE_SIZE) >> 20;
}
static void update_dirtyrate(uint64_t msec)
{
uint64_t dirtyrate;
uint64_t total_dirty_samples = DirtyStat.page_sampling.total_dirty_samples;
uint64_t total_sample_count = DirtyStat.page_sampling.total_sample_count;
uint64_t total_block_mem_MB = DirtyStat.page_sampling.total_block_mem_MB;
dirtyrate = total_dirty_samples * total_block_mem_MB *
1000 / (total_sample_count * msec);
DirtyStat.dirty_rate = dirtyrate;
}
/*
* get hash result for the sampled memory with length of TARGET_PAGE_SIZE
* in ramblock, which starts from ramblock base address.
*/
static uint32_t get_ramblock_vfn_hash(struct RamblockDirtyInfo *info,
uint64_t vfn)
{
uint32_t crc;
crc = crc32(0, (info->ramblock_addr +
vfn * TARGET_PAGE_SIZE), TARGET_PAGE_SIZE);
trace_get_ramblock_vfn_hash(info->idstr, vfn, crc);
return crc;
}
static bool save_ramblock_hash(struct RamblockDirtyInfo *info)
{
unsigned int sample_pages_count;
int i;
GRand *rand;
sample_pages_count = info->sample_pages_count;
/* ramblock size less than one page, return success to skip this ramblock */
if (unlikely(info->ramblock_pages == 0 || sample_pages_count == 0)) {
return true;
}
info->hash_result = g_try_malloc0_n(sample_pages_count,
sizeof(uint32_t));
if (!info->hash_result) {
return false;
}
info->sample_page_vfn = g_try_malloc0_n(sample_pages_count,
sizeof(uint64_t));
if (!info->sample_page_vfn) {
g_free(info->hash_result);
return false;
}
rand = g_rand_new();
for (i = 0; i < sample_pages_count; i++) {
info->sample_page_vfn[i] = g_rand_int_range(rand, 0,
info->ramblock_pages - 1);
info->hash_result[i] = get_ramblock_vfn_hash(info,
info->sample_page_vfn[i]);
}
g_rand_free(rand);
return true;
}
static void get_ramblock_dirty_info(RAMBlock *block,
struct RamblockDirtyInfo *info,
struct DirtyRateConfig *config)
{
uint64_t sample_pages_per_gigabytes = config->sample_pages_per_gigabytes;
/* Right shift 30 bits to calc ramblock size in GB */
info->sample_pages_count = (qemu_ram_get_used_length(block) *
sample_pages_per_gigabytes) >> 30;
/* Right shift TARGET_PAGE_BITS to calc page count */
info->ramblock_pages = qemu_ram_get_used_length(block) >>
TARGET_PAGE_BITS;
info->ramblock_addr = qemu_ram_get_host_addr(block);
strcpy(info->idstr, qemu_ram_get_idstr(block));
}
static void free_ramblock_dirty_info(struct RamblockDirtyInfo *infos, int count)
{
int i;
if (!infos) {
return;
}
for (i = 0; i < count; i++) {
g_free(infos[i].sample_page_vfn);
g_free(infos[i].hash_result);
}
g_free(infos);
}
static bool skip_sample_ramblock(RAMBlock *block)
{
/*
* Sample only blocks larger than MIN_RAMBLOCK_SIZE.
*/
if (qemu_ram_get_used_length(block) < (MIN_RAMBLOCK_SIZE << 10)) {
trace_skip_sample_ramblock(block->idstr,
qemu_ram_get_used_length(block));
return true;
}
return false;
}
static bool record_ramblock_hash_info(struct RamblockDirtyInfo **block_dinfo,
struct DirtyRateConfig config,
int *block_count)
{
struct RamblockDirtyInfo *info = NULL;
struct RamblockDirtyInfo *dinfo = NULL;
RAMBlock *block = NULL;
int total_count = 0;
int index = 0;
bool ret = false;
RAMBLOCK_FOREACH_MIGRATABLE(block) {
if (skip_sample_ramblock(block)) {
continue;
}
total_count++;
}
dinfo = g_try_malloc0_n(total_count, sizeof(struct RamblockDirtyInfo));
if (dinfo == NULL) {
goto out;
}
RAMBLOCK_FOREACH_MIGRATABLE(block) {
if (skip_sample_ramblock(block)) {
continue;
}
if (index >= total_count) {
break;
}
info = &dinfo[index];
get_ramblock_dirty_info(block, info, &config);
if (!save_ramblock_hash(info)) {
goto out;
}
index++;
}
ret = true;
out:
*block_count = index;
*block_dinfo = dinfo;
return ret;
}
static void calc_page_dirty_rate(struct RamblockDirtyInfo *info)
{
uint32_t crc;
int i;
for (i = 0; i < info->sample_pages_count; i++) {
crc = get_ramblock_vfn_hash(info, info->sample_page_vfn[i]);
if (crc != info->hash_result[i]) {
trace_calc_page_dirty_rate(info->idstr, crc, info->hash_result[i]);
info->sample_dirty_count++;
}
}
}
static struct RamblockDirtyInfo *
find_block_matched(RAMBlock *block, int count,
struct RamblockDirtyInfo *infos)
{
int i;
struct RamblockDirtyInfo *matched;
for (i = 0; i < count; i++) {
if (!strcmp(infos[i].idstr, qemu_ram_get_idstr(block))) {
break;
}
}
if (i == count) {
return NULL;
}
if (infos[i].ramblock_addr != qemu_ram_get_host_addr(block) ||
infos[i].ramblock_pages !=
(qemu_ram_get_used_length(block) >> TARGET_PAGE_BITS)) {
trace_find_page_matched(block->idstr);
return NULL;
}
matched = &infos[i];
return matched;
}
static bool compare_page_hash_info(struct RamblockDirtyInfo *info,
int block_count)
{
struct RamblockDirtyInfo *block_dinfo = NULL;
RAMBlock *block = NULL;
RAMBLOCK_FOREACH_MIGRATABLE(block) {
if (skip_sample_ramblock(block)) {
continue;
}
block_dinfo = find_block_matched(block, block_count, info);
if (block_dinfo == NULL) {
continue;
}
calc_page_dirty_rate(block_dinfo);
update_dirtyrate_stat(block_dinfo);
}
if (DirtyStat.page_sampling.total_sample_count == 0) {
return false;
}
return true;
}
static inline void record_dirtypages(DirtyPageRecord *dirty_pages,
CPUState *cpu, bool start)
{
if (start) {
dirty_pages[cpu->cpu_index].start_pages = cpu->dirty_pages;
} else {
dirty_pages[cpu->cpu_index].end_pages = cpu->dirty_pages;
}
}
static void dirtyrate_global_dirty_log_start(void)
{
qemu_mutex_lock_iothread();
memory_global_dirty_log_start(GLOBAL_DIRTY_DIRTY_RATE);
qemu_mutex_unlock_iothread();
}
static void dirtyrate_global_dirty_log_stop(void)
{
qemu_mutex_lock_iothread();
memory_global_dirty_log_sync();
memory_global_dirty_log_stop(GLOBAL_DIRTY_DIRTY_RATE);
qemu_mutex_unlock_iothread();
}
static int64_t do_calculate_dirtyrate_vcpu(DirtyPageRecord dirty_pages)
{
uint64_t memory_size_MB;
int64_t time_s;
uint64_t increased_dirty_pages =
dirty_pages.end_pages - dirty_pages.start_pages;
memory_size_MB = (increased_dirty_pages * TARGET_PAGE_SIZE) >> 20;
time_s = DirtyStat.calc_time;
return memory_size_MB / time_s;
}
static inline void record_dirtypages_bitmap(DirtyPageRecord *dirty_pages,
bool start)
{
if (start) {
dirty_pages->start_pages = total_dirty_pages;
} else {
dirty_pages->end_pages = total_dirty_pages;
}
}
static void do_calculate_dirtyrate_bitmap(DirtyPageRecord dirty_pages)
{
DirtyStat.dirty_rate = do_calculate_dirtyrate_vcpu(dirty_pages);
}
static inline void dirtyrate_manual_reset_protect(void)
{
RAMBlock *block = NULL;
WITH_RCU_READ_LOCK_GUARD() {
RAMBLOCK_FOREACH_MIGRATABLE(block) {
memory_region_clear_dirty_bitmap(block->mr, 0,
block->used_length);
}
}
}
static void calculate_dirtyrate_dirty_bitmap(struct DirtyRateConfig config)
{
int64_t msec = 0;
int64_t start_time;
DirtyPageRecord dirty_pages;
qemu_mutex_lock_iothread();
memory_global_dirty_log_start(GLOBAL_DIRTY_DIRTY_RATE);
/*
* 1'round of log sync may return all 1 bits with
* KVM_DIRTY_LOG_INITIALLY_SET enable
* skip it unconditionally and start dirty tracking
* from 2'round of log sync
*/
memory_global_dirty_log_sync();
/*
* reset page protect manually and unconditionally.
* this make sure kvm dirty log be cleared if
* KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE cap is enabled.
*/
dirtyrate_manual_reset_protect();
qemu_mutex_unlock_iothread();
record_dirtypages_bitmap(&dirty_pages, true);
start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
DirtyStat.start_time = start_time / 1000;
msec = config.sample_period_seconds * 1000;
msec = set_sample_page_period(msec, start_time);
DirtyStat.calc_time = msec / 1000;
/*
* dirtyrate_global_dirty_log_stop do two things.
* 1. fetch dirty bitmap from kvm
* 2. stop dirty tracking
*/
dirtyrate_global_dirty_log_stop();
record_dirtypages_bitmap(&dirty_pages, false);
do_calculate_dirtyrate_bitmap(dirty_pages);
}
static void calculate_dirtyrate_dirty_ring(struct DirtyRateConfig config)
{
CPUState *cpu;
int64_t msec = 0;
int64_t start_time;
uint64_t dirtyrate = 0;
uint64_t dirtyrate_sum = 0;
DirtyPageRecord *dirty_pages;
int nvcpu = 0;
int i = 0;
CPU_FOREACH(cpu) {
nvcpu++;
}
dirty_pages = malloc(sizeof(*dirty_pages) * nvcpu);
DirtyStat.dirty_ring.nvcpu = nvcpu;
DirtyStat.dirty_ring.rates = malloc(sizeof(DirtyRateVcpu) * nvcpu);
dirtyrate_global_dirty_log_start();
CPU_FOREACH(cpu) {
record_dirtypages(dirty_pages, cpu, true);
}
start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
DirtyStat.start_time = start_time / 1000;
msec = config.sample_period_seconds * 1000;
msec = set_sample_page_period(msec, start_time);
DirtyStat.calc_time = msec / 1000;
dirtyrate_global_dirty_log_stop();
CPU_FOREACH(cpu) {
record_dirtypages(dirty_pages, cpu, false);
}
for (i = 0; i < DirtyStat.dirty_ring.nvcpu; i++) {
dirtyrate = do_calculate_dirtyrate_vcpu(dirty_pages[i]);
trace_dirtyrate_do_calculate_vcpu(i, dirtyrate);
DirtyStat.dirty_ring.rates[i].id = i;
DirtyStat.dirty_ring.rates[i].dirty_rate = dirtyrate;
dirtyrate_sum += dirtyrate;
}
DirtyStat.dirty_rate = dirtyrate_sum;
free(dirty_pages);
}
static void calculate_dirtyrate_sample_vm(struct DirtyRateConfig config)
{
struct RamblockDirtyInfo *block_dinfo = NULL;
int block_count = 0;
int64_t msec = 0;
int64_t initial_time;
rcu_read_lock();
initial_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
if (!record_ramblock_hash_info(&block_dinfo, config, &block_count)) {
goto out;
}
rcu_read_unlock();
msec = config.sample_period_seconds * 1000;
msec = set_sample_page_period(msec, initial_time);
DirtyStat.start_time = initial_time / 1000;
DirtyStat.calc_time = msec / 1000;
rcu_read_lock();
if (!compare_page_hash_info(block_dinfo, block_count)) {
goto out;
}
update_dirtyrate(msec);
out:
rcu_read_unlock();
free_ramblock_dirty_info(block_dinfo, block_count);
}
static void calculate_dirtyrate(struct DirtyRateConfig config)
{
if (config.mode == DIRTY_RATE_MEASURE_MODE_DIRTY_BITMAP) {
calculate_dirtyrate_dirty_bitmap(config);
} else if (config.mode == DIRTY_RATE_MEASURE_MODE_DIRTY_RING) {
calculate_dirtyrate_dirty_ring(config);
} else {
calculate_dirtyrate_sample_vm(config);
}
trace_dirtyrate_calculate(DirtyStat.dirty_rate);
}
void *get_dirtyrate_thread(void *arg)
{
struct DirtyRateConfig config = *(struct DirtyRateConfig *)arg;
int ret;
rcu_register_thread();
ret = dirtyrate_set_state(&CalculatingState, DIRTY_RATE_STATUS_UNSTARTED,
DIRTY_RATE_STATUS_MEASURING);
if (ret == -1) {
error_report("change dirtyrate state failed.");
return NULL;
}
calculate_dirtyrate(config);
ret = dirtyrate_set_state(&CalculatingState, DIRTY_RATE_STATUS_MEASURING,
DIRTY_RATE_STATUS_MEASURED);
if (ret == -1) {
error_report("change dirtyrate state failed.");
}
rcu_unregister_thread();
return NULL;
}
void qmp_calc_dirty_rate(int64_t calc_time,
bool has_sample_pages,
int64_t sample_pages,
bool has_mode,
DirtyRateMeasureMode mode,
Error **errp)
{
static struct DirtyRateConfig config;
QemuThread thread;
int ret;
int64_t start_time;
/*
* If the dirty rate is already being measured, don't attempt to start.
*/
if (qatomic_read(&CalculatingState) == DIRTY_RATE_STATUS_MEASURING) {
error_setg(errp, "the dirty rate is already being measured.");
return;
}
if (!is_sample_period_valid(calc_time)) {
error_setg(errp, "calc-time is out of range[%d, %d].",
MIN_FETCH_DIRTYRATE_TIME_SEC,
MAX_FETCH_DIRTYRATE_TIME_SEC);
return;
}
if (!has_mode) {
mode = DIRTY_RATE_MEASURE_MODE_PAGE_SAMPLING;
}
if (has_sample_pages && mode == DIRTY_RATE_MEASURE_MODE_DIRTY_RING) {
error_setg(errp, "either sample-pages or dirty-ring can be specified.");
return;
}
if (has_sample_pages) {
if (!is_sample_pages_valid(sample_pages)) {
error_setg(errp, "sample-pages is out of range[%d, %d].",
MIN_SAMPLE_PAGE_COUNT,
MAX_SAMPLE_PAGE_COUNT);
return;
}
} else {
sample_pages = DIRTYRATE_DEFAULT_SAMPLE_PAGES;
}
/*
* dirty ring mode only works when kvm dirty ring is enabled.
* on the contrary, dirty bitmap mode is not.
*/
if (((mode == DIRTY_RATE_MEASURE_MODE_DIRTY_RING) &&
!kvm_dirty_ring_enabled()) ||
((mode == DIRTY_RATE_MEASURE_MODE_DIRTY_BITMAP) &&
kvm_dirty_ring_enabled())) {
error_setg(errp, "mode %s is not enabled, use other method instead.",
DirtyRateMeasureMode_str(mode));
return;
}
/*
* Init calculation state as unstarted.
*/
ret = dirtyrate_set_state(&CalculatingState, CalculatingState,
DIRTY_RATE_STATUS_UNSTARTED);
if (ret == -1) {
error_setg(errp, "init dirty rate calculation state failed.");
return;
}
config.sample_period_seconds = calc_time;
config.sample_pages_per_gigabytes = sample_pages;
config.mode = mode;
cleanup_dirtyrate_stat(config);
/*
* update dirty rate mode so that we can figure out what mode has
* been used in last calculation
**/
dirtyrate_mode = mode;
start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) / 1000;
init_dirtyrate_stat(start_time, config);
qemu_thread_create(&thread, "get_dirtyrate", get_dirtyrate_thread,
(void *)&config, QEMU_THREAD_DETACHED);
}
struct DirtyRateInfo *qmp_query_dirty_rate(Error **errp)
{
return query_dirty_rate_info();
}
void hmp_info_dirty_rate(Monitor *mon, const QDict *qdict)
{
DirtyRateInfo *info = query_dirty_rate_info();
monitor_printf(mon, "Status: %s\n",
DirtyRateStatus_str(info->status));
monitor_printf(mon, "Start Time: %"PRIi64" (ms)\n",
info->start_time);
monitor_printf(mon, "Sample Pages: %"PRIu64" (per GB)\n",
info->sample_pages);
monitor_printf(mon, "Period: %"PRIi64" (sec)\n",
info->calc_time);
monitor_printf(mon, "Mode: %s\n",
DirtyRateMeasureMode_str(info->mode));
monitor_printf(mon, "Dirty rate: ");
if (info->has_dirty_rate) {
monitor_printf(mon, "%"PRIi64" (MB/s)\n", info->dirty_rate);
if (info->has_vcpu_dirty_rate) {
DirtyRateVcpuList *rate, *head = info->vcpu_dirty_rate;
for (rate = head; rate != NULL; rate = rate->next) {
monitor_printf(mon, "vcpu[%"PRIi64"], Dirty rate: %"PRIi64
" (MB/s)\n", rate->value->id,
rate->value->dirty_rate);
}
}
} else {
monitor_printf(mon, "(not ready)\n");
}
qapi_free_DirtyRateVcpuList(info->vcpu_dirty_rate);
g_free(info);
}
void hmp_calc_dirty_rate(Monitor *mon, const QDict *qdict)
{
int64_t sec = qdict_get_try_int(qdict, "second", 0);
int64_t sample_pages = qdict_get_try_int(qdict, "sample_pages_per_GB", -1);
bool has_sample_pages = (sample_pages != -1);
bool dirty_ring = qdict_get_try_bool(qdict, "dirty_ring", false);
bool dirty_bitmap = qdict_get_try_bool(qdict, "dirty_bitmap", false);
DirtyRateMeasureMode mode = DIRTY_RATE_MEASURE_MODE_PAGE_SAMPLING;
Error *err = NULL;
if (!sec) {
monitor_printf(mon, "Incorrect period length specified!\n");
return;
}
if (dirty_ring && dirty_bitmap) {
monitor_printf(mon, "Either dirty ring or dirty bitmap "
"can be specified!\n");
return;
}
if (dirty_bitmap) {
mode = DIRTY_RATE_MEASURE_MODE_DIRTY_BITMAP;
} else if (dirty_ring) {
mode = DIRTY_RATE_MEASURE_MODE_DIRTY_RING;
}
qmp_calc_dirty_rate(sec, has_sample_pages, sample_pages, true,
mode, &err);
if (err) {
hmp_handle_error(mon, err);
return;
}
monitor_printf(mon, "Starting dirty rate measurement with period %"PRIi64
" seconds\n", sec);
monitor_printf(mon, "[Please use 'info dirty_rate' to check results]\n");
}