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| author | Javier Cardona <javier@cozybit.com> | 2012-04-12 14:32:23 -0700 |
|---|---|---|
| committer | John W. Linville <linville@tuxdriver.com> | 2012-04-16 14:19:29 -0400 |
| commit | ec14bcd20f5139a3dc42cfc34cdcebcbdc062c00 (patch) | |
| tree | ef7122cf0abbf407db9c0c0ce4eb9dd03b94e16b | |
| parent | a802a6eba13282ddd5718f8db9d476e42e84e2ba (diff) | |
| download | olio-linux-3.10-ec14bcd20f5139a3dc42cfc34cdcebcbdc062c00.tar.xz olio-linux-3.10-ec14bcd20f5139a3dc42cfc34cdcebcbdc062c00.zip | |
mac80211: Take into account TSF adjustment latency in Toffset setpoint
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@gmail.com>
Signed-off-by: Yu Niiro <yu.niiro@gmail.com>
Signed-off-by: Javier Cardona <javier@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
| -rw-r--r-- | 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 22a5f1e6699..ff60d6bcc63 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 { |