>> s->iteration_start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); >>+ /* >>+ * Update s->iteration_initial_bytes to match s->iteration_start_time. >>+ */ >>+ s->iteration_initial_bytes = migration_total_bytes(s); > >Is this one necessary? We have sent out nothing yet.
Yes, currently nothing has been sent yet at this point. Is that better to always match the update of iteration_initial_bytes and iteration_start_time in a explicit way to avoid some potential missing? Thanks. On Thu, Aug 1, 2019 at 10:21 AM Wei Yang <richardw.y...@linux.intel.com> wrote: > On Tue, Jul 30, 2019 at 01:36:32PM +0800, Ivan Ren wrote: > >From: Ivan Ren <ivan...@tencent.com> > > > >This patch fix a multifd migration bug in migration speed calculation, > this > >problem can be reproduced as follows: > >1. start a vm and give a heavy memory write stress to prevent the vm be > > successfully migrated to destination > >2. begin a migration with multifd > >3. migrate for a long time [actually, this can be measured by transferred > bytes] > >4. migrate cancel > >5. begin a new migration with multifd, the migration will directly run > into > > migration_completion phase > > > >Reason as follows: > > > >Migration update bandwidth and s->threshold_size in function > >migration_update_counters after BUFFER_DELAY time: > > > > current_bytes = migration_total_bytes(s); > > transferred = current_bytes - s->iteration_initial_bytes; > > time_spent = current_time - s->iteration_start_time; > > bandwidth = (double)transferred / time_spent; > > s->threshold_size = bandwidth * s->parameters.downtime_limit; > > > >In multifd migration, migration_total_bytes function return > >qemu_ftell(s->to_dst_file) + ram_counters.multifd_bytes. > >s->iteration_initial_bytes will be initialized to 0 at every new > migration, > >but ram_counters is a global variable, and history migration data will be > >accumulated. So if the ram_counters.multifd_bytes is big enough, it may > lead > >pending_size >= s->threshold_size become false in migration_iteration_run > >after the first migration_update_counters. > > > >Signed-off-by: Ivan Ren <ivan...@tencent.com> > >--- > > migration/migration.c | 15 ++++++++++++++- > > migration/savevm.c | 1 + > > 2 files changed, 15 insertions(+), 1 deletion(-) > > > >diff --git a/migration/migration.c b/migration/migration.c > >index 8a607fe1e2..d35a6ae6f9 100644 > >--- a/migration/migration.c > >+++ b/migration/migration.c > >@@ -1908,6 +1908,11 @@ static bool migrate_prepare(MigrationState *s, > bool blk, bool blk_inc, > > } > > > > migrate_init(s); > >+ /* > >+ * set ram_counters memory to zero for a > >+ * new migration > >+ */ > >+ memset(&ram_counters, 0, sizeof(ram_counters)); > > > > return true; > > } > >@@ -3187,6 +3192,10 @@ static void *migration_thread(void *opaque) > > > > object_ref(OBJECT(s)); > > s->iteration_start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); > >+ /* > >+ * Update s->iteration_initial_bytes to match > s->iteration_start_time. > >+ */ > >+ s->iteration_initial_bytes = migration_total_bytes(s); > > Is this one necessary? We have sent out nothing yet. > > > > > qemu_savevm_state_header(s->to_dst_file); > > > >@@ -3252,7 +3261,11 @@ static void *migration_thread(void *opaque) > > * breaking transferred_bytes and bandwidth calculation > > */ > > s->iteration_start_time = > qemu_clock_get_ms(QEMU_CLOCK_REALTIME); > >- s->iteration_initial_bytes = 0; > >+ /* > >+ * Update s->iteration_initial_bytes to current size to > >+ * avoid historical data lead wrong bandwidth. > >+ */ > >+ s->iteration_initial_bytes = migration_total_bytes(s); > > } > > > > current_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); > >diff --git a/migration/savevm.c b/migration/savevm.c > >index 79ed44d475..480c511b19 100644 > >--- a/migration/savevm.c > >+++ b/migration/savevm.c > >@@ -1424,6 +1424,7 @@ static int qemu_savevm_state(QEMUFile *f, Error > **errp) > > } > > > > migrate_init(ms); > >+ memset(&ram_counters, 0, sizeof(ram_counters)); > > ms->to_dst_file = f; > > > > qemu_mutex_unlock_iothread(); > >-- > >2.17.2 (Apple Git-113) > > > > -- > Wei Yang > Help you, Help me >
