When testing mesh synchronization we observed a global TSF slowdown that
was dependent on the number of synchronized mesh stations. This seems
to be caused by the TSF adjustment (read/write) latency.
Adding a small margin to the Toffset setpoint solved the problem.
Signed-off-by: Shinichi Hotori <hotorinn@xxxxxxxxx>
Signed-off-by: Yu Niiro <yu.niiro@xxxxxxxxx>
Signed-off-by: Javier Cardona <javier@xxxxxxxxxxx>
---
net/mac80211/mesh_sync.c | 8 +++++++-
1 files changed, 7 insertions(+), 1 deletions(-)
diff --git a/net/mac80211/mesh_sync.c b/net/mac80211/mesh_sync.c
index 22a5f1e..ff60d6b 100644
--- a/net/mac80211/mesh_sync.c
+++ b/net/mac80211/mesh_sync.c
@@ -24,11 +24,17 @@
*/
#define TOFFSET_MINIMUM_ADJUSTMENT 10
+/* This is not in the standard. It is a margin added to the
+ * Toffset setpoint to mitigate TSF overcorrection
+ * introduced by TSF adjustment latency.
+ */
+#define TOFFSET_SET_MARGIN 20
+
/* This is not in the standard. It represents the maximum Toffset jump above
* which we'll invalidate the Toffset setpoint and choose a new setpoint. This
* could be, for instance, in case a neighbor is restarted and its TSF counter
* reset.
- * */
+ */
#define TOFFSET_MAXIMUM_ADJUSTMENT 30000 /* 30 ms */
struct sync_method {
--
1.7.5.4
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