diff mbox series

[v4,18/23] qapi: backup: disable copy_range by default

Message ID 20210116214705.822267-19-vsementsov@virtuozzo.com
State New
Headers show
Series backup performance: block_status + async | expand

Commit Message

Vladimir Sementsov-Ogievskiy Jan. 16, 2021, 9:47 p.m. UTC
Further commit will add a benchmark
(scripts/simplebench/bench-backup.py), which will show that backup
works better with async parallel requests (previous commit) and
disabled copy_range. So, let's disable copy_range by default.

Note: the option was added several commits ago with default to true,
to follow old behavior (the feature was enabled unconditionally), and
only now we are going to change the default behavior.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
---
 qapi/block-core.json | 2 +-
 blockdev.c           | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/qapi/block-core.json b/qapi/block-core.json
index c0e9d119d2..933c2327c8 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -1377,7 +1377,7 @@ 
 # Optional parameters for backup. These parameters don't affect
 # functionality, but may significantly affect performance.
 #
-# @use-copy-range: Use copy offloading. Default true.
+# @use-copy-range: Use copy offloading. Default false.
 #
 # @max-workers: Maximum number of parallel requests for the sustained background
 #               copying process. Doesn't influence copy-before-write operations.
diff --git a/blockdev.c b/blockdev.c
index 6db433cef8..41d1431210 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -2794,7 +2794,7 @@  static BlockJob *do_backup_common(BackupCommon *backup,
 {
     BlockJob *job = NULL;
     BdrvDirtyBitmap *bmap = NULL;
-    BackupPerf perf = { .use_copy_range = true, .max_workers = 64 };
+    BackupPerf perf = { .max_workers = 64 };
     int job_flags = JOB_DEFAULT;
 
     if (!backup->has_speed) {