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migration/dirtyrate: Refactor dirty page rate calculation

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abstract out dirty log change logic into function
global_dirty_log_change.

abstract out dirty page rate calculation logic via
dirty-ring into function vcpu_calculate_dirtyrate.

abstract out mathematical dirty page rate calculation
into do_calculate_dirtyrate, decouple it from DirtyStat.

rename set_sample_page_period to dirty_stat_wait, which
is well-understood and will be reused in dirtylimit.

handle cpu hotplug/unplug scenario during measurement of
dirty page rate.

export util functions outside migration.

Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
Reviewed-by: Peter Xu <peterx@redhat.com>
Message-Id: <7b6f6f4748d5b3d017b31a0429e630229ae97538.1656177590.git.huangy81@chinatelecom.cn>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
This commit is contained in:
Hyman Huang(黄勇) 2022-06-26 01:38:32 +08:00 committed by Dr. David Alan Gilbert
parent ab1a161fe3
commit 8244166dec
3 changed files with 174 additions and 88 deletions
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28
include/sysemu/dirtyrate.h Normal file
View file

@ -0,0 +1,28 @@
/*
* dirty page rate helper functions
*
* Copyright (c) 2022 CHINA TELECOM CO.,LTD.
*
* Authors:
* Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#ifndef QEMU_DIRTYRATE_H
#define QEMU_DIRTYRATE_H
typedef struct VcpuStat {
int nvcpu; /* number of vcpu */
DirtyRateVcpu *rates; /* array of dirty rate for each vcpu */
} VcpuStat;
int64_t vcpu_calculate_dirtyrate(int64_t calc_time_ms,
VcpuStat *stat,
unsigned int flag,
bool one_shot);
void global_dirty_log_change(unsigned int flag,
bool start);
#endif

227
migration/dirtyrate.c
View file

@ -46,7 +46,7 @@ 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)
static int64_t dirty_stat_wait(int64_t msec, int64_t initial_time)
{
int64_t current_time;
@ -60,6 +60,132 @@ static int64_t set_sample_page_period(int64_t msec, int64_t initial_time)
return msec;
}
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 int64_t do_calculate_dirtyrate(DirtyPageRecord dirty_pages,
int64_t calc_time_ms)
{
uint64_t memory_size_MB;
uint64_t increased_dirty_pages =
dirty_pages.end_pages - dirty_pages.start_pages;
memory_size_MB = (increased_dirty_pages * TARGET_PAGE_SIZE) >> 20;
return memory_size_MB * 1000 / calc_time_ms;
}
void global_dirty_log_change(unsigned int flag, bool start)
{
qemu_mutex_lock_iothread();
if (start) {
memory_global_dirty_log_start(flag);
} else {
memory_global_dirty_log_stop(flag);
}
qemu_mutex_unlock_iothread();
}
/*
* global_dirty_log_sync
* 1. sync dirty log from kvm
* 2. stop dirty tracking if needed.
*/
static void global_dirty_log_sync(unsigned int flag, bool one_shot)
{
qemu_mutex_lock_iothread();
memory_global_dirty_log_sync();
if (one_shot) {
memory_global_dirty_log_stop(flag);
}
qemu_mutex_unlock_iothread();
}
static DirtyPageRecord *vcpu_dirty_stat_alloc(VcpuStat *stat)
{
CPUState *cpu;
DirtyPageRecord *records;
int nvcpu = 0;
CPU_FOREACH(cpu) {
nvcpu++;
}
stat->nvcpu = nvcpu;
stat->rates = g_malloc0(sizeof(DirtyRateVcpu) * nvcpu);
records = g_malloc0(sizeof(DirtyPageRecord) * nvcpu);
return records;
}
static void vcpu_dirty_stat_collect(VcpuStat *stat,
DirtyPageRecord *records,
bool start)
{
CPUState *cpu;
CPU_FOREACH(cpu) {
record_dirtypages(records, cpu, start);
}
}
int64_t vcpu_calculate_dirtyrate(int64_t calc_time_ms,
VcpuStat *stat,
unsigned int flag,
bool one_shot)
{
DirtyPageRecord *records;
int64_t init_time_ms;
int64_t duration;
int64_t dirtyrate;
int i = 0;
unsigned int gen_id;
retry:
init_time_ms = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
cpu_list_lock();
gen_id = cpu_list_generation_id_get();
records = vcpu_dirty_stat_alloc(stat);
vcpu_dirty_stat_collect(stat, records, true);
cpu_list_unlock();
duration = dirty_stat_wait(calc_time_ms, init_time_ms);
global_dirty_log_sync(flag, one_shot);
cpu_list_lock();
if (gen_id != cpu_list_generation_id_get()) {
g_free(records);
g_free(stat->rates);
cpu_list_unlock();
goto retry;
}
vcpu_dirty_stat_collect(stat, records, false);
cpu_list_unlock();
for (i = 0; i < stat->nvcpu; i++) {
dirtyrate = do_calculate_dirtyrate(records[i], duration);
stat->rates[i].id = i;
stat->rates[i].dirty_rate = dirtyrate;
trace_dirtyrate_do_calculate_vcpu(i, dirtyrate);
}
g_free(records);
return duration;
}
static bool is_sample_period_valid(int64_t sec)
{
if (sec < MIN_FETCH_DIRTYRATE_TIME_SEC ||
@ -396,44 +522,6 @@ static bool compare_page_hash_info(struct RamblockDirtyInfo *info,
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)
{
@ -444,11 +532,6 @@ static inline void record_dirtypages_bitmap(DirtyPageRecord *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;
@ -492,71 +575,49 @@ static void calculate_dirtyrate_dirty_bitmap(struct DirtyRateConfig config)
DirtyStat.start_time = start_time / 1000;
msec = config.sample_period_seconds * 1000;
msec = set_sample_page_period(msec, start_time);
msec = dirty_stat_wait(msec, start_time);
DirtyStat.calc_time = msec / 1000;
/*
* dirtyrate_global_dirty_log_stop do two things.
* do two things.
* 1. fetch dirty bitmap from kvm
* 2. stop dirty tracking
*/
dirtyrate_global_dirty_log_stop();
global_dirty_log_sync(GLOBAL_DIRTY_DIRTY_RATE, true);
record_dirtypages_bitmap(&dirty_pages, false);
do_calculate_dirtyrate_bitmap(dirty_pages);
DirtyStat.dirty_rate = do_calculate_dirtyrate(dirty_pages, msec);
}
static void calculate_dirtyrate_dirty_ring(struct DirtyRateConfig config)
{
CPUState *cpu;
int64_t msec = 0;
int64_t start_time;
int64_t duration;
uint64_t dirtyrate = 0;
uint64_t dirtyrate_sum = 0;
DirtyPageRecord *dirty_pages;
int nvcpu = 0;
int i = 0;
CPU_FOREACH(cpu) {
nvcpu++;
}
/* start log sync */
global_dirty_log_change(GLOBAL_DIRTY_DIRTY_RATE, true);
dirty_pages = malloc(sizeof(*dirty_pages) * nvcpu);
DirtyStat.start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) / 1000;
DirtyStat.dirty_ring.nvcpu = nvcpu;
DirtyStat.dirty_ring.rates = malloc(sizeof(DirtyRateVcpu) * nvcpu);
/* calculate vcpu dirtyrate */
duration = vcpu_calculate_dirtyrate(config.sample_period_seconds * 1000,
&DirtyStat.dirty_ring,
GLOBAL_DIRTY_DIRTY_RATE,
true);
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);
}
DirtyStat.calc_time = duration / 1000;
/* calculate vm dirtyrate */
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;
dirtyrate = DirtyStat.dirty_ring.rates[i].dirty_rate;
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)
@ -574,7 +635,7 @@ static void calculate_dirtyrate_sample_vm(struct DirtyRateConfig config)
rcu_read_unlock();
msec = config.sample_period_seconds * 1000;
msec = set_sample_page_period(msec, initial_time);
msec = dirty_stat_wait(msec, initial_time);
DirtyStat.start_time = initial_time / 1000;
DirtyStat.calc_time = msec / 1000;

7
migration/dirtyrate.h
View file

@ -13,6 +13,8 @@
#ifndef QEMU_MIGRATION_DIRTYRATE_H
#define QEMU_MIGRATION_DIRTYRATE_H
#include "sysemu/dirtyrate.h"
/*
* Sample 512 pages per GB as default.
*/
@ -65,11 +67,6 @@ typedef struct SampleVMStat {
uint64_t total_block_mem_MB; /* size of total sampled pages in MB */
} SampleVMStat;
typedef struct VcpuStat {
int nvcpu; /* number of vcpu */
DirtyRateVcpu *rates; /* array of dirty rate for each vcpu */
} VcpuStat;
/*
* Store calculation statistics for each measure.
*/