We have quite a few lines in migration_thread() that calculates some
statistics for the migration interations. Isolate it into a single
function to improve readability.
Signed-off-by: Peter Xu <pet...@redhat.com>
---
migration/migration.c | 82 +++++++++++++++++++++++++++++----------------------
migration/migration.h | 13 ++++++++
2 files changed, 59 insertions(+), 36 deletions(-)
diff --git a/migration/migration.c b/migration/migration.c
index bfcba24caa..2629f907e9 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -1273,6 +1273,8 @@ MigrationState *migrate_init(void)
s->mig_start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
s->mig_total_time = 0;
s->old_vm_running = false;
+ s->initial_bytes = 0;
+ s->threshold_size = 0;
return s;
}
@@ -2164,6 +2166,39 @@ static void migration_calculate_complete(MigrationState
*s)
}
}
+static void migration_update_statistics(MigrationState *s,
+ int64_t current_time)
+{
+ uint64_t transferred = qemu_ftell(s->to_dst_file) - s->initial_bytes;
+ uint64_t time_spent = current_time - s->initial_time;
+ double bandwidth = (double)transferred / time_spent;
+ int64_t threshold_size = bandwidth * s->parameters.downtime_limit;
+
+ if (current_time < s->initial_time + BUFFER_DELAY) {
+ return;
+ }
+
+ s->mbps = (((double) transferred * 8.0) /
+ ((double) time_spent / 1000.0)) / 1000.0 / 1000.0;
+
+ /*
+ * if we haven't sent anything, we don't want to
+ * recalculate. 10000 is a small enough number for our purposes
+ */
+ if (ram_counters.dirty_pages_rate && transferred > 10000) {
+ s->expected_downtime = ram_counters.dirty_pages_rate *
+ qemu_target_page_size() / bandwidth;
+ }
+
+ qemu_file_reset_rate_limit(s->to_dst_file);
+
+ s->initial_time = current_time;
+ s->initial_bytes = qemu_ftell(s->to_dst_file);
+
+ trace_migrate_transferred(transferred, time_spent,
+ bandwidth, threshold_size);
+}
+
/*
* Master migration thread on the source VM.
* It drives the migration and pumps the data down the outgoing channel.
@@ -2171,22 +2206,15 @@ static void migration_calculate_complete(MigrationState
*s)
static void *migration_thread(void *opaque)
{
MigrationState *s = opaque;
- /* Used by the bandwidth calcs, updated later */
- int64_t initial_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
int64_t setup_start = qemu_clock_get_ms(QEMU_CLOCK_HOST);
- int64_t initial_bytes = 0;
- /*
- * The final stage happens when the remaining data is smaller than
- * this threshold; it's calculated from the requested downtime and
- * measured bandwidth
- */
- int64_t threshold_size = 0;
bool entered_postcopy = false;
/* The active state we expect to be in; ACTIVE or POSTCOPY_ACTIVE */
enum MigrationStatus current_active_state = MIGRATION_STATUS_ACTIVE;
rcu_register_thread();
+ s->initial_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
+
qemu_savevm_state_header(s->to_dst_file);
/*
@@ -2226,17 +2254,17 @@ static void *migration_thread(void *opaque)
if (!qemu_file_rate_limit(s->to_dst_file)) {
uint64_t pend_post, pend_nonpost;
- qemu_savevm_state_pending(s->to_dst_file, threshold_size,
+ qemu_savevm_state_pending(s->to_dst_file, s->threshold_size,
&pend_nonpost, &pend_post);
pending_size = pend_nonpost + pend_post;
- trace_migrate_pending(pending_size, threshold_size,
+ trace_migrate_pending(pending_size, s->threshold_size,
pend_post, pend_nonpost);
- if (pending_size && pending_size >= threshold_size) {
+ if (pending_size && pending_size >= s->threshold_size) {
/* Still a significant amount to transfer */
if (migrate_postcopy() &&
s->state != MIGRATION_STATUS_POSTCOPY_ACTIVE &&
- pend_nonpost <= threshold_size &&
+ pend_nonpost <= s->threshold_size &&
atomic_read(&s->start_postcopy)) {
if (!postcopy_start(s)) {
@@ -2261,33 +2289,15 @@ static void *migration_thread(void *opaque)
trace_migration_thread_file_err();
break;
}
+
current_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
- if (current_time >= initial_time + BUFFER_DELAY) {
- uint64_t transferred_bytes = qemu_ftell(s->to_dst_file) -
- initial_bytes;
- uint64_t time_spent = current_time - initial_time;
- double bandwidth = (double)transferred_bytes / time_spent;
- threshold_size = bandwidth * s->parameters.downtime_limit;
-
- s->mbps = (((double) transferred_bytes * 8.0) /
- ((double) time_spent / 1000.0)) / 1000.0 / 1000.0;
-
- trace_migrate_transferred(transferred_bytes, time_spent,
- bandwidth, threshold_size);
- /* if we haven't sent anything, we don't want to recalculate
- 10000 is a small enough number for our purposes */
- if (ram_counters.dirty_pages_rate && transferred_bytes > 10000) {
- s->expected_downtime = ram_counters.dirty_pages_rate *
- qemu_target_page_size() / bandwidth;
- }
- qemu_file_reset_rate_limit(s->to_dst_file);
- initial_time = current_time;
- initial_bytes = qemu_ftell(s->to_dst_file);
- }
+ /* Conditionally update statistics */
+ migration_update_statistics(s, current_time);
+
if (qemu_file_rate_limit(s->to_dst_file)) {
/* usleep expects microseconds */
- g_usleep((initial_time + BUFFER_DELAY - current_time)*1000);
+ g_usleep((s->initial_time + BUFFER_DELAY - current_time) * 1000);
}
}
diff --git a/migration/migration.h b/migration/migration.h
index 3ab5506233..248f7d9a5c 100644
--- a/migration/migration.h
+++ b/migration/migration.h
@@ -90,6 +90,19 @@ struct MigrationState
QEMUBH *cleanup_bh;
QEMUFile *to_dst_file;
+ /*
+ * Migration thread statistic variables, mostly used in
+ * migration_thread() iterations only.
+ */
+ uint64_t initial_bytes;
+ int64_t initial_time;
+ /*
+ * The final stage happens when the remaining data is smaller than
+ * this threshold; it's calculated from the requested downtime and
+ * measured bandwidth
+ */
+ int64_t threshold_size;
+
/* params from 'migrate-set-parameters' */
MigrationParameters parameters;
--
2.14.3
