Bug #272

Description

———- Forwarded message ———-
From: Kalle Valo kvalo@qca.qualcomm.com
Date: Mon, Sep 19, 2011 at 11:38 AM
Subject: [PATCH] ath6kl: pass only unicast frames for aggregation
To: linux-wireless@vger.kernel.org

When pinging form ar6003 to the AP RTT was high even when power save was
disabled:

100 packets transmitted, 97 received, 3% packet loss, time 99125ms
rtt min/avg/max/mdev = 1.⁸⁷⁵⁄₄₆.⁷³³⁄₇₉₅.⁵⁰⁶⁄₁₃₉.181 ms

After some investigation one reason for this was that received
multicast traffic confused the aggrecation logic and caused 400 ms
timeouts when receiving multicast frames from AP.

A simple way to fix is to pass only unicast frames for aggregation. This
improves RTT:

100 packets transmitted, 99 received, 1% packet loss, time 99144ms
rtt min/avg/max/mdev = 2.083/13.084/403.³⁹⁰⁄₅₆.794 ms

Signed-off-by: Kalle Valo kvalo@qca.qualcomm.com
—
 drivers/net/wireless/ath/ath6kl/txrx.c |   16 **+——-
 1 files changed, 9 insertions(+), 7 deletions(-)

diff –git a/drivers/net/wireless/ath/ath6kl/txrx.c
b/drivers/net/wireless/ath/ath6kl/txrx.c
index fffd929..348c646 100644
— a/drivers/net/wireless/ath/ath6kl/txrx.c
**+ b/drivers/net/wireless/ath/ath6kl/txrx.c
@ -1230,9 +1230,15@ void ath6kl_rx(struct htc_target *target,
struct htc_packet *packet)
                       ath6kl_data_tx(skb1, ar->net_dev);
       }

•       if (!aggr_process_recv_frm(ar->aggr_cntxt, tid, seq_no,
  
•                                  is_amsdu, skb))
  
•               ath6kl_deliver_frames_to_nw_stack(ar->net_dev, skb);
  
•       datap = (struct ethhdr *) skb->data;
  +
  
•       if (is_unicast_ether_addr(datap->h_dest) &&
  
•           aggr_process_recv_frm(ar->aggr_cntxt, tid, seq_no,
  
•                                 is_amsdu, skb))
  
•               /* aggregation code will handle the skb */
  
•               return;
  +
  
•       ath6kl_deliver_frames_to_nw_stack(ar->net_dev, skb);
   }

 static void aggr_timeout(unsigned long arg)
@ -1249,10 +1255,6@ static void aggr_timeout(unsigned long arg)
               if (rxtid->timer_mon || rxtid->progress)
                       continue;

•               /*
  
•                * FIXME: these timeouts happen quite fruently, something
  
•                * line once within 60 seconds. Investigate why.
  
•                */
                 stats->num_timeouts++;
                 ath6kl_dbg(ATH6KL_DBG_AGGR,
                            “aggr timeout (st %d end %d)\n”,