Re: [PATCH 3/3] mac80211: mesh: Add support for HW RC implementation

[Johannes Berg]

> - if (sta->mesh->fail_avg >= 100)
> - return MAX_METRIC;
> + /* try to get rate based on HW RC algorithm */
> + rate = drv_get_expected_throughput(local, >sta);

This doesn't look correct, since you should use the rate control op if
available, to get data from rate control algorithms.

You should call sta_set_sinfo(), but that's far too much, so more
likely you should factor out the last few lines of that into a new
function and call that new function in both places.

johannes

[PATCH 3/3] mac80211: mesh: Add support for HW RC implementation

[Maxim Altshul]

Mesh HWMP module will be able to rely on the HW
RC algorithm if it exists, for path metric calculations.

This allows the metric calculation mechanism to calculate
a correct metric, based on PER and last TX rate both via
HW RC algorithm if it exists or via parameters collected
by the SW.

Signed-off-by: Maxim Altshul 
---
 net/mac80211/mesh_hwmp.c | 23 +++
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/net/mac80211/mesh_hwmp.c b/net/mac80211/mesh_hwmp.c
index c6be0b4..e3ce40d 100644
--- a/net/mac80211/mesh_hwmp.c
+++ b/net/mac80211/mesh_hwmp.c
@@ -12,6 +12,7 @@
 #include 
 #include "wme.h"
 #include "mesh.h"
+#include "driver-ops.h"
 
 #define TEST_FRAME_LEN 8192
 #define MAX_METRIC 0x
@@ -322,19 +323,25 @@ static u32 airtime_link_metric_get(struct ieee80211_local 
*local,
int device_constant = 1 << ARITH_SHIFT;
int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
int s_unit = 1 << ARITH_SHIFT;
-   int rate, err;
+   int rate, err = 0;
u32 tx_time, estimated_retx;
u64 result;
 
-   if (sta->mesh->fail_avg >= 100)
-   return MAX_METRIC;
+   /* try to get rate based on HW RC algorithm */
+   rate = drv_get_expected_throughput(local, >sta);
 
-   sta_set_rate_info_tx(sta, >tx_stats.last_rate, );
-   rate = cfg80211_calculate_bitrate();
-   if (WARN_ON(!rate))
-   return MAX_METRIC;
+   /* if HW does not provide us with a rate */
+   if (!rate) {
+   if (sta->mesh->fail_avg >= 100)
+   return MAX_METRIC;
 
-   err = (sta->mesh->fail_avg << ARITH_SHIFT) / 100;
+   sta_set_rate_info_tx(sta, >tx_stats.last_rate, );
+   rate = cfg80211_calculate_bitrate();
+   if (WARN_ON(!rate))
+   return MAX_METRIC;
+
+   err = (sta->mesh->fail_avg << ARITH_SHIFT) / 100;
+   }
 
/* bitrate is in units of 100 Kbps, while we need rate in units of
 * 1Mbps. This will be corrected on tx_time computation.
-- 
2.7.2