[Qemu-devel] [PATCH v4 3/6] Postcopy: Add stats on page requests

[Dr. David Alan Gilbert (git)]

From: "Dr. David Alan Gilbert" <dgilb...@redhat.com>

On the source, add a count of page requests received from the
destination.

Signed-off-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
Reviewed-by: Eric Blake <ebl...@redhat.com>
Reviewed-by: Denis V. Lunev <d...@openvz.org>
---
 hmp.c                         | 4 ++++
 include/migration/migration.h | 2 ++
 migration/migration.c         | 2 ++
 migration/ram.c               | 1 +
 qapi-schema.json              | 6 +++++-
 5 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/hmp.c b/hmp.c
index d510236..cd5fae3 100644
--- a/hmp.c
+++ b/hmp.c
@@ -209,6 +209,10 @@ void hmp_info_migrate(Monitor *mon, const QDict *qdict)
             monitor_printf(mon, "dirty pages rate: %" PRIu64 " pages\n",
                            info->ram->dirty_pages_rate);
         }
+        if (info->ram->postcopy_requests) {
+            monitor_printf(mon, "postcopy request count: %" PRIu64 "\n",
+                           info->ram->postcopy_requests);
+        }
     }
 
     if (info->has_disk) {
diff --git a/include/migration/migration.h b/include/migration/migration.h
index ac2c12c..78fa59b 100644
--- a/include/migration/migration.h
+++ b/include/migration/migration.h
@@ -157,6 +157,8 @@ struct MigrationState
     int64_t xbzrle_cache_size;
     int64_t setup_time;
     int64_t dirty_sync_count;
+    /* Count of requests incoming from destination */
+    int64_t postcopy_requests;
 
     /* Flag set once the migration has been asked to enter postcopy */
     bool start_postcopy;
diff --git a/migration/migration.c b/migration/migration.c
index bfb326d..9d41618 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -573,6 +573,7 @@ static void populate_ram_info(MigrationInfo *info, 
MigrationState *s)
     info->ram->normal_bytes = norm_mig_bytes_transferred();
     info->ram->mbps = s->mbps;
     info->ram->dirty_sync_count = s->dirty_sync_count;
+    info->ram->postcopy_requests = s->postcopy_requests;
 
     if (s->state != MIGRATION_STATUS_COMPLETED) {
         info->ram->remaining = ram_bytes_remaining();
@@ -933,6 +934,7 @@ MigrationState *migrate_init(const MigrationParams *params)
     s->dirty_sync_count = 0;
     s->start_postcopy = false;
     s->postcopy_after_devices = false;
+    s->postcopy_requests = 0;
     s->migration_thread_running = false;
     s->last_req_rb = NULL;
 
diff --git a/migration/ram.c b/migration/ram.c
index e96c2af..eeb1902 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -1169,6 +1169,7 @@ int ram_save_queue_pages(MigrationState *ms, const char 
*rbname,
 {
     RAMBlock *ramblock;
 
+    ms->postcopy_requests++;
     rcu_read_lock();
     if (!rbname) {
         /* Reuse last RAMBlock */
diff --git a/qapi-schema.json b/qapi-schema.json
index 54634c4..8bc581e 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -382,13 +382,17 @@
 #
 # @dirty-sync-count: number of times that dirty ram was synchronized (since 
2.1)
 #
+# @postcopy-requests: The number of page requests received from the destination
+#        (since 2.7)
+#
 # Since: 0.14.0
 ##
 { 'struct': 'MigrationStats',
   'data': {'transferred': 'int', 'remaining': 'int', 'total': 'int' ,
            'duplicate': 'int', 'skipped': 'int', 'normal': 'int',
            'normal-bytes': 'int', 'dirty-pages-rate' : 'int',
-           'mbps' : 'number', 'dirty-sync-count' : 'int' } }
+           'mbps' : 'number', 'dirty-sync-count' : 'int',
+           'postcopy-requests' : 'int' } }
 
 ##
 # @XBZRLECacheStats
-- 
2.5.5