[Qemu-devel] [PATCH] migration: fix divide-by-zero introduced by sleep time accounting

[Anthony Liguori]

If current_time == (initial_time + sleep_time), since
sleep_time == BUFFER_DELAY, time_spent will be 0 resulting in a
divide-by-zero when computing bandwidth.

This was introduced by:

  commit 7161082c8d8cf167c508976887a0a63f4db92b51
  Author: Juan Quintela <address@hidden>
  Date:   Fri Feb 1 12:41:38 2013 +0100

      migration: don't account sleep time for calculating bandwidth

Cc: Juan Quintela <address@hidden>
Reported-by: Mike Roth <address@hidden>
Signed-off-by: Anthony Liguori <address@hidden>
---
 migration.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/migration.c b/migration.c
index 3eb0fad..70ae7a9 100644
--- a/migration.c
+++ b/migration.c
@@ -539,7 +539,7 @@ static void *migration_thread(void *opaque)
             break;
         }
         current_time = qemu_get_clock_ms(rt_clock);
-        if (current_time >= initial_time + BUFFER_DELAY) {
+        if ((current_time - sleep_time) >= initial_time + BUFFER_DELAY) {
             uint64_t transferred_bytes = qemu_ftell(s->file) - initial_bytes;
             uint64_t time_spent = current_time - initial_time - sleep_time;
             double bandwidth = transferred_bytes / time_spent;
-- 
1.8.0