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[Qemu-devel] [PATCH] migration: keep bytes_xfer_prev init'd to zero
From: |
Felipe Franciosi |
Subject: |
[Qemu-devel] [PATCH] migration: keep bytes_xfer_prev init'd to zero |
Date: |
Fri, 19 May 2017 22:59:02 +0100 |
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>
~
---
migration/ram.c | 4 ----
1 file changed, 4 deletions(-)
diff --git a/migration/ram.c b/migration/ram.c
index f59fdd4..793af39 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -670,10 +670,6 @@ 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);
}
--
1.9.5
- [Qemu-devel] [PATCH] migration: keep bytes_xfer_prev init'd to zero,
Felipe Franciosi <=