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authorLukas Straub <lukasstraub2@web.de>2020-05-11 13:10:44 +0200
committerDr. David Alan Gilbert <dgilbert@redhat.com>2020-06-01 18:44:27 +0100
commitbb70b66ed7a5600a63437fb6d64dedb44f670e58 (patch)
treedcac9bc50eb0326987316259efe0b8de4e210cd1 /migration/migration.h
parente0d138aa9b3a4c72fe8bca735686132fdea646b7 (diff)
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migration/colo.c: Use event instead of semaphore
If multiple packets miscompare in a short timeframe, the semaphore value will be increased multiple times. This causes multiple checkpoints even if one would be sufficient. Fix this by using a event instead of a semaphore for triggering checkpoints. Now, checkpoint requests will be ignored until the checkpoint event is sent to colo-compare (which releases the miscompared packets). Benchmark results (iperf3): Client-to-server tcp: without patch: ~66 Mbit/s with patch: ~61 Mbit/s Server-to-client tcp: without patch: ~702 Kbit/s with patch: ~16 Mbit/s Signed-off-by: Lukas Straub <lukasstraub2@web.de> Message-Id: <fd601ba1beb524aada54ba66e87ebfc12cf4574b.1589193382.git.lukasstraub2@web.de> Reviewed-by: zhanghailiang <zhang.zhanghailiang@huawei.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Diffstat (limited to 'migration/migration.h')
-rw-r--r--migration/migration.h4
1 files changed, 2 insertions, 2 deletions
diff --git a/migration/migration.h b/migration/migration.h
index 507284e..f617960 100644
--- a/migration/migration.h
+++ b/migration/migration.h
@@ -215,8 +215,8 @@ struct MigrationState
/* The semaphore is used to notify COLO thread that failover is finished */
QemuSemaphore colo_exit_sem;
- /* The semaphore is used to notify COLO thread to do checkpoint */
- QemuSemaphore colo_checkpoint_sem;
+ /* The event is used to notify COLO thread to do checkpoint */
+ QemuEvent colo_checkpoint_event;
int64_t colo_checkpoint_time;
QEMUTimer *colo_delay_timer;