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[Qemu-devel] [PULL 2/5] migration: keep bytes_xfer_prev init'd to zero
From: |
Juan Quintela |
Subject: |
[Qemu-devel] [PULL 2/5] migration: keep bytes_xfer_prev init'd to zero |
Date: |
Wed, 31 May 2017 11:15:35 +0200 |
From: Felipe Franciosi <address@hidden>
The first time migration_bitmap_sync() is called, bytes_xfer_prev is set
to ram_state.bytes_transferred which is, at this point, zero. The next
time migration_bitmap_sync() is called, an iteration has happened and
bytes_xfer_prev is set to 'x' bytes. Most likely, more than one second
has passed, so the auto converge logic will be triggered and
bytes_xfer_now will also be set to 'x' bytes.
This condition is currently masked by dirty_rate_high_cnt, which will
wait for a few iterations before throttling. It would otherwise always
assume zero bytes have been copied and therefore throttle the guest
(possibly) prematurely.
Given bytes_xfer_prev is only used by the auto convergence logic, it
makes sense to only set its value after a check has been made against
bytes_xfer_now.
Signed-off-by: Felipe Franciosi <address@hidden>
Reviewed-by: Peter Xu <address@hidden>
Reviewed-by: Juan Quintela <address@hidden>
Signed-off-by: Juan Quintela <address@hidden>
---
migration/ram.c | 4 ----
1 file changed, 4 deletions(-)
diff --git a/migration/ram.c b/migration/ram.c
index c07a9c0..36bf720 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -673,10 +673,6 @@ static void migration_bitmap_sync(RAMState *rs)
rs->bitmap_sync_count++;
- if (!rs->bytes_xfer_prev) {
- rs->bytes_xfer_prev = ram_bytes_transferred();
- }
-
if (!rs->time_last_bitmap_sync) {
rs->time_last_bitmap_sync = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
}
--
2.9.4
- [Qemu-devel] [PULL 1/5] migration: Fix regression with compression threads, (continued)
- [Qemu-devel] [PULL 1/5] migration: Fix regression with compression threads, Juan Quintela, 2017/05/12
- [Qemu-devel] [PULL 3/5] ram: Rename RAM_SAVE_FLAG_COMPRESS to RAM_SAVE_FLAG_ZERO, Juan Quintela, 2017/05/12
- [Qemu-devel] [PULL 4/5] migration: Create block capabilities for shared and enable, Juan Quintela, 2017/05/12
- [Qemu-devel] [PULL 5/5] migration: Create migration/blocker.h, Juan Quintela, 2017/05/12
- [Qemu-devel] [PULL 2/5] migration: Pass Error ** argument to {save, load}_vmstate, Juan Quintela, 2017/05/12
- Re: [Qemu-devel] [PULL 0/5] Migration pull request, Stefan Hajnoczi, 2017/05/15
- Re: [Qemu-devel] [PULL 0/5] Migration pull request, Stefan Hajnoczi, 2017/05/16
- [Qemu-devel] [PULL 0/5] Migration pull request, Juan Quintela, 2017/05/31