linux.git/net/mac80211/mesh_sync.c, branch v3.5 Linux kernel source tree mac80211: fixup for mesh TSF adjustment latency in Toffset setpoint 2012-04-23T19:37:41+00:00 Javier Cardona javier@cozybit.com 2012-04-20T16:52:56+00:00 6ac95b57657d1bf5776f29a1697c123f62d5a58a The original patch defined the correction margin but did not apply it. 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> 
The original patch defined the correction margin but did not apply it.

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>
mac80211: Take into account TSF adjustment latency in Toffset setpoint 2012-04-16T18:19:29+00:00 Javier Cardona javier@cozybit.com 2012-04-12T21:32:23+00:00 ec14bcd20f5139a3dc42cfc34cdcebcbdc062c00 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> 
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>
mac80211: Choose a new toffset setpoint if a big tsf jump is detected. 2012-04-16T18:19:29+00:00 Javier Cardona javier@cozybit.com 2012-04-12T21:32:22+00:00 a802a6eba13282ddd5718f8db9d476e42e84e2ba Signed-off-by: Javier Cardona <javier@cozybit.com> Signed-off-by: John W. Linville <linville@tuxdriver.com> 
Signed-off-by: Javier Cardona <javier@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
mac80211: Implement mesh synchronization framework 2012-04-10T19:20:31+00:00 Javier Cardona javier@cozybit.com 2012-03-31T18:31:32+00:00 dbf498fbafa2c23139d5a990e94ed78bafbbea19 This patch adds MBSS extensible synchronization framework (Sec. 13.13.2 of IEEE Std. 802.11-2012). The framework is implemented via an ops table which defines the following functions: rx_bcn_presp() - this is called every time a mesh beacon is received. adjust_tbtt() - this is called immediately before a beacon is about to be transmitted. The default neighbor offset synchronization defined in the standard is implemented. We also provide template functions for vendor specific methods. When neighbor offset synchronization is active (which is the default) mesh neighbors in the same MBSS will track timing offsets to each other and compensate clock drift. In our tests we observed that this mesh synchronization implementation successfully corrected drifts between stations of ~2PPM while introducing a jitter of ~20us. It is also possible to test this framework on mac80211_hwsim simulated phys to see how it behaves under different topologies, over poor links, etc. Signed-off-by: Marco Porsch <marco.porsch@s2005.tu-chemnitz.de> Signed-off-by: Pavel Zubarev <pavel.zubarev@gmail.com> Signed-off-by: Javier Cardona <javier@cozybit.com> Signed-off-by: John W. Linville <linville@tuxdriver.com> 
This patch adds MBSS extensible synchronization framework (Sec.
13.13.2 of IEEE Std. 802.11-2012).

The framework is implemented via an ops table which defines the
following functions:

    rx_bcn_presp() - this is called every time a mesh beacon is
received.
    adjust_tbtt() - this is called immediately before a beacon is about
to be transmitted.

The default neighbor offset synchronization defined in the standard is
implemented.  We also provide template functions for vendor specific
methods.

When neighbor offset synchronization is active (which is the default)
mesh neighbors in the same MBSS will track timing offsets to each other
and compensate clock drift.

In our tests we observed that this mesh synchronization implementation
successfully corrected drifts between stations of ~2PPM while
introducing a jitter of ~20us.

It is also possible to test this framework on mac80211_hwsim simulated
phys to see how it behaves under different topologies, over poor links,
etc.

Signed-off-by: Marco Porsch <marco.porsch@s2005.tu-chemnitz.de>
Signed-off-by: Pavel Zubarev <pavel.zubarev@gmail.com>
Signed-off-by: Javier Cardona <javier@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>