We noticed these while testing mesh synchronization.
Javier Cardona (4):
mac80211: Set the correct values for hwmp (1) and airtimeLinkMetric
(1)
mac80211_hwsim: fixup for tsf setting
mac80211: Choose a new toffset setpoint if a big tsf jump is
detected.
mac80211: Take into account TSF adjustment latency in Toffset
setpoint
drivers/net/wireless/mac80211_hwsim.c | 1 +
include/linux/ieee80211.h | 4 ++--
net/mac80211/mesh_sync.c | 32 ++++++++++++++++++++++++++------
3 files changed, 29 insertions(+), 8 deletions(-)
--
1.7.5.4
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 <[email protected]>
Signed-off-by: Yu Niiro <[email protected]>
Signed-off-by: Javier Cardona <[email protected]>
---
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
On Thu, 2012-04-12 at 14:32 -0700, Javier Cardona wrote:
> We noticed these while testing mesh synchronization.
I think these patches were merged, but there seems to have been some
confusion about what changes belong into what patch -- please try to be
more careful about that.
Also -- no users for TOFFSET_SET_MARGIN?
johannes
Signed-off-by: Javier Cardona <[email protected]>
---
net/mac80211/mesh_sync.c | 26 ++++++++++++++++++++------
1 files changed, 20 insertions(+), 6 deletions(-)
diff --git a/net/mac80211/mesh_sync.c b/net/mac80211/mesh_sync.c
index f78b013..22a5f1e 100644
--- a/net/mac80211/mesh_sync.c
+++ b/net/mac80211/mesh_sync.c
@@ -22,7 +22,14 @@
/* This is not in the standard. It represents a tolerable tbtt drift below
* which we do no TSF adjustment.
*/
-#define TBTT_MINIMUM_ADJUSTMENT 10
+#define TOFFSET_MINIMUM_ADJUSTMENT 10
+
+/* 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 {
u8 method;
@@ -156,15 +163,22 @@ static void mesh_sync_offset_rx_bcn_presp(struct ieee80211_sub_if_data *sdata,
if (test_sta_flag(sta, WLAN_STA_TOFFSET_KNOWN)) {
s64 t_clockdrift = sta->t_offset_setpoint
- sta->t_offset;
-
- msync_dbg("STA %pM : sta->t_offset=%lld,"
- " sta->t_offset_setpoint=%lld,"
- " t_clockdrift=%lld",
+ msync_dbg("STA %pM : sta->t_offset=%lld, sta->t_offset_setpoint=%lld, t_clockdrift=%lld",
sta->sta.addr,
(long long) sta->t_offset,
(long long)
sta->t_offset_setpoint,
(long long) t_clockdrift);
+
+ if (t_clockdrift > TOFFSET_MAXIMUM_ADJUSTMENT ||
+ t_clockdrift < -TOFFSET_MAXIMUM_ADJUSTMENT) {
+ msync_dbg("STA %pM : t_clockdrift=%lld too large, setpoint reset",
+ sta->sta.addr,
+ (long long) t_clockdrift);
+ clear_sta_flag(sta, WLAN_STA_TOFFSET_KNOWN);
+ goto no_sync;
+ }
+
rcu_read_unlock();
spin_lock_bh(&ifmsh->sync_offset_lock);
@@ -200,7 +214,7 @@ static void mesh_sync_offset_adjust_tbtt(struct ieee80211_sub_if_data *sdata)
spin_lock_bh(&ifmsh->sync_offset_lock);
if (ifmsh->sync_offset_clockdrift_max >
- TBTT_MINIMUM_ADJUSTMENT) {
+ TOFFSET_MINIMUM_ADJUSTMENT) {
/* Since ajusting the tsf here would
* require a possibly blocking call
* to the driver tsf setter, we punt
--
1.7.5.4
Per sections 8.4.2.100.2 and 8.4.2.100.3 of Std 802.11-2012
Reported-by: Shinichi Hotori <[email protected]>
Signed-off-by: Javier Cardona <[email protected]>
---
include/linux/ieee80211.h | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/linux/ieee80211.h b/include/linux/ieee80211.h
index db84e2f..ce9af89 100644
--- a/include/linux/ieee80211.h
+++ b/include/linux/ieee80211.h
@@ -1458,7 +1458,7 @@ enum {
* be specified in a vendor specific information element
*/
enum {
- IEEE80211_PATH_PROTOCOL_HWMP = 0,
+ IEEE80211_PATH_PROTOCOL_HWMP = 1,
IEEE80211_PATH_PROTOCOL_VENDOR = 255,
};
@@ -1470,7 +1470,7 @@ enum {
* specified in a vendor specific information element
*/
enum {
- IEEE80211_PATH_METRIC_AIRTIME = 0,
+ IEEE80211_PATH_METRIC_AIRTIME = 1,
IEEE80211_PATH_METRIC_VENDOR = 255,
};
--
1.7.5.4
Last patch I sent failed to take into account the offset of each phy.
Signed-off-by: Javier Cardona <[email protected]>
---
drivers/net/wireless/mac80211_hwsim.c | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)
diff --git a/drivers/net/wireless/mac80211_hwsim.c b/drivers/net/wireless/mac80211_hwsim.c
index 2d2bfce..3edd473 100644
--- a/drivers/net/wireless/mac80211_hwsim.c
+++ b/drivers/net/wireless/mac80211_hwsim.c
@@ -694,6 +694,7 @@ static bool mac80211_hwsim_tx_frame_no_nl(struct ieee80211_hw *hw,
ieee80211_is_probe_resp(mgmt->frame_control))
mgmt->u.beacon.timestamp = cpu_to_le64(
rx_status.mactime +
+ (data->tsf_offset - data2->tsf_offset) +
24 * 8 * 10 / txrate->bitrate);
memcpy(IEEE80211_SKB_RXCB(nskb), &rx_status, sizeof(rx_status));
--
1.7.5.4