Re: [PATCH 03/21] migration: We set the rate_limit by a second

[Cédric Le Goater]

On 5/8/23 15:08, Juan Quintela wrote:

That the implementation does the check every 100 milliseconds is an
implementation detail that shouldn't be seen on the interfaz.

Si. Pero, "interface" es mejor aqui.

Notice that all callers of qemu_file_set_rate_limit() used the
division or pass 0, so this change is a NOP.

Signed-off-by: Juan Quintela <quint...@redhat.com>

Reviewed-by: Cédric Le Goater <c...@kaod.org>

C.

---
  migration/migration.c | 7 +++----
  migration/options.c   | 4 ++--
  migration/qemu-file.c | 6 +++++-
  3 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/migration/migration.c b/migration/migration.c
index 3979a98949..e17a6538b4 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -2117,7 +2117,7 @@ static int postcopy_start(MigrationState *ms)
       * will notice we're in POSTCOPY_ACTIVE and not actually
       * wrap their state up here
       */
-    qemu_file_set_rate_limit(ms->to_dst_file, bandwidth / XFER_LIMIT_RATIO);
+    qemu_file_set_rate_limit(ms->to_dst_file, bandwidth);
      if (migrate_postcopy_ram()) {
          /* Ping just for debugging, helps line traces up */
          qemu_savevm_send_ping(ms->to_dst_file, 2);
@@ -3207,11 +3207,10 @@ void migrate_fd_connect(MigrationState *s, Error 
*error_in)

if (resume) {

          /* This is a resumed migration */
-        rate_limit = migrate_max_postcopy_bandwidth() /
-            XFER_LIMIT_RATIO;
+        rate_limit = migrate_max_postcopy_bandwidth();
      } else {
          /* This is a fresh new migration */
-        rate_limit = migrate_max_bandwidth() / XFER_LIMIT_RATIO;
+        rate_limit = migrate_max_bandwidth();

/* Notify before starting migration thread */

          notifier_list_notify(&migration_state_notifiers, s);
diff --git a/migration/options.c b/migration/options.c
index 2e759cc306..d04b5fbc3a 100644
--- a/migration/options.c
+++ b/migration/options.c
@@ -1243,7 +1243,7 @@ static void migrate_params_apply(MigrateSetParameters 
*params, Error **errp)
          s->parameters.max_bandwidth = params->max_bandwidth;
          if (s->to_dst_file && !migration_in_postcopy()) {
              qemu_file_set_rate_limit(s->to_dst_file,
-                                s->parameters.max_bandwidth / 
XFER_LIMIT_RATIO);
+                                s->parameters.max_bandwidth);
          }
      }

@@ -1275,7 +1275,7 @@ static void migrate_params_apply(MigrateSetParameters *params, Error **errp)

          s->parameters.max_postcopy_bandwidth = params->max_postcopy_bandwidth;
          if (s->to_dst_file && migration_in_postcopy()) {
              qemu_file_set_rate_limit(s->to_dst_file,
-                    s->parameters.max_postcopy_bandwidth / XFER_LIMIT_RATIO);
+                    s->parameters.max_postcopy_bandwidth);
          }
      }
      if (params->has_max_cpu_throttle) {
diff --git a/migration/qemu-file.c b/migration/qemu-file.c
index 745361d238..12cf7fb04e 100644
--- a/migration/qemu-file.c
+++ b/migration/qemu-file.c
@@ -29,6 +29,7 @@
  #include "migration.h"
  #include "qemu-file.h"
  #include "trace.h"
+#include "options.h"
  #include "qapi/error.h"

#define IO_BUF_SIZE 32768

@@ -747,7 +748,10 @@ int64_t qemu_file_get_rate_limit(QEMUFile *f)

void qemu_file_set_rate_limit(QEMUFile *f, int64_t limit)

  {
-    f->rate_limit_max = limit;
+    /*
+     * 'limit' is per second.  But we check it each 100 miliseconds.
+     */
+    f->rate_limit_max = limit / XFER_LIMIT_RATIO;
  }

void qemu_file_reset_rate_limit(QEMUFile *f)