Collect number of dirty pages for progresseively increasing time
periods starting with 125ms up to number of seconds specified with
calc-dirty-rate. Report through qmp and hmp: 1) vector of dirty page
measurements, 2) page size, 3) total number of VM pages, 4) number
of sampled pages.
Signed-off-by: Andrei Gudkov <gudkov.and...@huawei.com>
---
migration/dirtyrate.c | 165 +++++++++++++++++++++++++++++-------------
migration/dirtyrate.h | 25 ++++++-
qapi/migration.json | 24 +++++-
3 files changed, 160 insertions(+), 54 deletions(-)
diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c
index acba3213a3..4491bbe91a 100644
--- a/migration/dirtyrate.c
+++ b/migration/dirtyrate.c
@@ -224,6 +224,7 @@ static struct DirtyRateInfo *query_dirty_rate_info(void)
info->calc_time = DirtyStat.calc_time;
info->sample_pages = DirtyStat.sample_pages;
info->mode = dirtyrate_mode;
+ info->page_size = TARGET_PAGE_SIZE;
if (qatomic_read(&CalculatingState) == DIRTY_RATE_STATUS_MEASURED) {
info->has_dirty_rate = true;
@@ -245,6 +246,29 @@ static struct DirtyRateInfo *query_dirty_rate_info(void)
info->vcpu_dirty_rate = head;
}
+ if (dirtyrate_mode == DIRTY_RATE_MEASURE_MODE_PAGE_SAMPLING) {
+ int64List *periods_head = NULL;
+ int64List **periods_tail = &periods_head;
+ int64List *n_dirty_pages_head = NULL;
+ int64List **n_dirty_pages_tail = &n_dirty_pages_head;
+
+ info->n_total_pages = DirtyStat.page_sampling.n_total_pages;
+ info->has_n_total_pages = true;
+
+ info->n_sampled_pages = DirtyStat.page_sampling.n_sampled_pages;
+ info->has_n_sampled_pages = true;
+
+ for (i = 0; i < DirtyStat.page_sampling.n_readings; i++) {
+ DirtyReading *dr = &DirtyStat.page_sampling.readings[i];
+ QAPI_LIST_APPEND(periods_tail, dr->period);
+ QAPI_LIST_APPEND(n_dirty_pages_tail, dr->n_dirty_pages);
+ }
+ info->n_dirty_pages = n_dirty_pages_head;
+ info->periods = periods_head;
+ info->has_n_dirty_pages = true;
+ info->has_periods = true;
+ }
+
if (dirtyrate_mode == DIRTY_RATE_MEASURE_MODE_DIRTY_BITMAP) {
info->sample_pages = 0;
}
@@ -265,9 +289,11 @@ static void init_dirtyrate_stat(int64_t start_time,
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;
+ DirtyStat.page_sampling.n_total_pages = 0;
+ DirtyStat.page_sampling.n_sampled_pages = 0;
+ DirtyStat.page_sampling.n_readings = 0;
+ DirtyStat.page_sampling.readings = g_try_malloc0_n(MAX_DIRTY_READINGS,
+
sizeof(DirtyReading));
break;
case DIRTY_RATE_MEASURE_MODE_DIRTY_RING:
DirtyStat.dirty_ring.nvcpu = -1;
@@ -285,28 +311,10 @@ static void cleanup_dirtyrate_stat(struct DirtyRateConfig
config)
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;
+ if (DirtyStat.page_sampling.readings) {
+ free(DirtyStat.page_sampling.readings);
+ DirtyStat.page_sampling.readings = NULL;
+ }
}
/*
@@ -377,12 +385,14 @@ static bool save_ramblock_hash(struct RamblockDirtyInfo
*info)
return false;
}
- rand = g_rand_new();
+ rand = g_rand_new();
+ DirtyStat.page_sampling.n_total_pages += info->ramblock_pages;
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]);
+ DirtyStat.page_sampling.n_sampled_pages++;
}
g_rand_free(rand);
@@ -479,18 +489,20 @@ out:
return ret;
}
-static void calc_page_dirty_rate(struct RamblockDirtyInfo *info)
+static int64_t calc_page_dirty_rate(struct RamblockDirtyInfo *info)
{
uint32_t hash;
int i;
+ int64_t n_dirty = 0;
for (i = 0; i < info->sample_pages_count; i++) {
hash = get_ramblock_vfn_hash(info, info->sample_page_vfn[i]);
if (hash != info->hash_result[i]) {
+ n_dirty++;
trace_calc_page_dirty_rate(info->idstr, hash,
info->hash_result[i]);
- info->sample_dirty_count++;
}
}
+ return n_dirty;
}
static struct RamblockDirtyInfo *
@@ -519,11 +531,12 @@ find_block_matched(RAMBlock *block, int count,
return &infos[i];
}
-static bool compare_page_hash_info(struct RamblockDirtyInfo *info,
+static int64_t compare_page_hash_info(struct RamblockDirtyInfo *info,
int block_count)
{
struct RamblockDirtyInfo *block_dinfo = NULL;
RAMBlock *block = NULL;
+ int64_t n_dirty = 0;
RAMBLOCK_FOREACH_MIGRATABLE(block) {
if (skip_sample_ramblock(block)) {
@@ -533,15 +546,10 @@ static bool compare_page_hash_info(struct
RamblockDirtyInfo *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;
+ n_dirty += calc_page_dirty_rate(block_dinfo);
}
- return true;
+ return n_dirty;
}
static inline void record_dirtypages_bitmap(DirtyPageRecord *dirty_pages,
@@ -642,34 +650,77 @@ static void calculate_dirtyrate_dirty_ring(struct
DirtyRateConfig config)
DirtyStat.dirty_rate = dirtyrate_sum;
}
+static int64_t increase_period(int64_t prev_period, int64_t max_period)
+{
+ int64_t delta;
+ int64_t next_period;
+
+ if (prev_period < 500) {
+ delta = 125;
+ } else if (prev_period < 1000) {
+ delta = 250;
+ } else if (prev_period < 2000) {
+ delta = 500;
+ } else if (prev_period < 4000) {
+ delta = 1000;
+ } else if (prev_period < 10000) {
+ delta = 2000;
+ } else {
+ delta = 5000;
+ }
+
+ next_period = prev_period + delta;
+ if (next_period + delta >= max_period) {
+ next_period = max_period;
+ }
+ return next_period;
+}
+
+
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;
+ int64_t current_time;
+ /* initial pass */
rcu_read_lock();
initial_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
- if (!record_ramblock_hash_info(&block_dinfo, config, &block_count)) {
+ bool ok = record_ramblock_hash_info(&block_dinfo, config, &block_count);
+ rcu_read_unlock();
+ if ((!ok) || (DirtyStat.page_sampling.n_sampled_pages == 0)) {
goto out;
}
- rcu_read_unlock();
- msec = config.sample_period_seconds * 1000;
- msec = dirty_stat_wait(msec, initial_time);
- DirtyStat.start_time = initial_time / 1000;
- DirtyStat.calc_time = msec / 1000;
+ int64_t period = INITIAL_PERIOD_MS;
+ while (true) {
+ current_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
+ int64_t delta = initial_time + period - current_time;
+ if (delta > 0) {
+ g_usleep(delta * 1000);
+ }
- rcu_read_lock();
- if (!compare_page_hash_info(block_dinfo, block_count)) {
- goto out;
- }
+ rcu_read_lock();
+ current_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
+ int64_t n_dirty = compare_page_hash_info(block_dinfo, block_count);
+ rcu_read_unlock();
- update_dirtyrate(msec);
+ SampleVMStat *ps = &DirtyStat.page_sampling;
+ ps->readings[ps->n_readings].period = current_time - initial_time;
+ ps->readings[ps->n_readings].n_dirty_pages = n_dirty;
+ ps->n_readings++;
+
+ if (period >= DirtyStat.calc_time * 1000) {
+ int64_t mb_total = (ps->n_total_pages * TARGET_PAGE_SIZE) >> 20;
+ int64_t mb_dirty = n_dirty * mb_total / ps->n_sampled_pages;
+ DirtyStat.dirty_rate = mb_dirty * 1000 / period;
+ break;
+ }
+ period = increase_period(period, DirtyStat.calc_time * 1000);
+ }
out:
- rcu_read_unlock();
free_ramblock_dirty_info(block_dinfo, block_count);
}
@@ -836,7 +887,23 @@ void hmp_info_dirty_rate(Monitor *mon, const QDict *qdict)
monitor_printf(mon, "(not ready)\n");
}
+ if (info->has_n_total_pages) {
+ monitor_printf(mon, "Page count (page size %d):\n", TARGET_PAGE_SIZE);
+ monitor_printf(mon, " Total: %"PRIi64"\n", info->n_total_pages);
+ monitor_printf(mon, " Sampled: %"PRIi64"\n", info->n_sampled_pages);
+ int64List *periods = info->periods;
+ int64List *n_dirty_pages = info->n_dirty_pages;
+ while (periods) {
+ monitor_printf(mon, " Dirty(%"PRIi64"ms): %"PRIi64"\n",
+ periods->value, n_dirty_pages->value);
+ periods = periods->next;
+ n_dirty_pages = n_dirty_pages->next;
+ }
+ }
+
qapi_free_DirtyRateVcpuList(info->vcpu_dirty_rate);
+ qapi_free_int64List(info->periods);
+ qapi_free_int64List(info->n_dirty_pages);
g_free(info);
}
diff --git a/migration/dirtyrate.h b/migration/dirtyrate.h
index 594a5c0bb6..7a97e2b076 100644
--- a/migration/dirtyrate.h
+++ b/migration/dirtyrate.h
@@ -42,6 +42,18 @@
#define MIN_SAMPLE_PAGE_COUNT 128
#define MAX_SAMPLE_PAGE_COUNT 16384
+/*
+ * Initial sampling period expressed in milliseconds
+ */
+#define INITIAL_PERIOD_MS 125
+
+/*
+ * Upper bound on the number of DirtyReadings calculcated based on
+ * INITIAL_PERIOD_MS, MAX_FETCH_DIRTYRATE_TIME_SEC and increase_period()
+ */
+#define MAX_DIRTY_READINGS 32
+
+
struct DirtyRateConfig {
uint64_t sample_pages_per_gigabytes; /* sample pages per GB */
int64_t sample_period_seconds; /* time duration between two sampling */
@@ -57,14 +69,19 @@ struct RamblockDirtyInfo {
uint64_t ramblock_pages; /* ramblock size in TARGET_PAGE_SIZE */
uint64_t *sample_page_vfn; /* relative offset address for sampled page */
uint64_t sample_pages_count; /* count of sampled pages */
- uint64_t sample_dirty_count; /* count of dirty pages we measure */
uint32_t *hash_result; /* array of hash result for sampled pages */
};
+typedef struct DirtyReading {
+ int64_t period; /* time period in milliseconds */
+ int64_t n_dirty_pages; /* number of observed dirty pages */
+} DirtyReading;
+
typedef struct SampleVMStat {
- uint64_t total_dirty_samples; /* total dirty sampled page */
- uint64_t total_sample_count; /* total sampled pages */
- uint64_t total_block_mem_MB; /* size of total sampled pages in MB */
+ int64_t n_total_pages; /* total number of pages */
+ int64_t n_sampled_pages; /* number of sampled pages */
+ int64_t n_readings;
+ DirtyReading *readings;
} SampleVMStat;
/*
diff --git a/qapi/migration.json b/qapi/migration.json
index 2c35b7b9cf..f818f51e0e 100644
--- a/qapi/migration.json
+++ b/qapi/migration.json
@@ -1805,6 +1805,22 @@
# @vcpu-dirty-rate: dirtyrate for each vcpu if dirty-ring
# mode specified (Since 6.2)
#
+# @page-size: page size in bytes (since 8.1)
+#
+# @n-total-pages: [page-sampling] total number of VM pages (since 8.1)
+#
+# @n-sampled-pages: [page-sampling] number of sampled VM pages (since 8.1)
+#
+# @periods: [page-sampling] array of time periods expressed in milliseconds
+# for which dirty-sample measurements were collected (since 8.1)
+#
+# @n-dirty-pages: [page-sampling] number of pages among all sampled pages
+# that were observed as changed during respective time period.
+# i-th element of this array corresponds to the i-th element
+# of the @periods array, i.e. @n-dirty-pages[i] is the number
+# of dirtied pages during period of @periods[i] milliseconds
+# after the initiation of calc-dirty-rate (since 8.1)
+#
# Since: 5.2
##
{ 'struct': 'DirtyRateInfo',
@@ -1814,7 +1830,13 @@
'calc-time': 'int64',
'sample-pages': 'uint64',
'mode': 'DirtyRateMeasureMode',
- '*vcpu-dirty-rate': [ 'DirtyRateVcpu' ] } }
+ '*vcpu-dirty-rate': [ 'DirtyRateVcpu' ],
+ 'page-size': 'int64',
+ '*n-total-pages': 'int64',
+ '*n-sampled-pages': 'int64',
+ '*periods': ['int64'],
+ '*n-dirty-pages': ['int64'] } }
+
##
# @calc-dirty-rate:
--
2.30.2
