net: rmnet_data: Further optimize UL aggregation accumulation

Do not aggregate frames if they are sapced out more than 10ms. Since the
scedule_delayed_work() API only takes time in jiffies, ping packets
are getting substantially delayed. Instead, just send them. This parameter
is tunable from the module parameters location.

CRs-Fixed: 772705
Change-Id: I6ac337c8d61b1290f939b86081070c14c2c757b1
Signed-off-by: Harout Hedeshian <harouth@codeaurora.org>

3 files changed, 35 insertions, 4 deletions

diff --git a/net/rmnet_data/rmnet_data_config.h b/net/rmnet_data/rmnet_data_config.h
index 6bacad45980e..fe668a86eb45 100644
--- a/net/rmnet_data/rmnet_data_config.h
+++ b/net/rmnet_data/rmnet_data_config.h
@@ -59,6 +59,7 @@ struct rmnet_logical_ep_conf_s {
  *                  aggregation
  * @tail_spacing: Guaranteed padding (bytes) when de-aggregating ingress frames
  * @agg_time: Wall clock time when aggregated frame was created
+ * @agg_last: Last time the aggregation routing was invoked
  */
 struct rmnet_phys_ep_conf_s {
 	struct net_device *dev;
@@ -70,12 +71,17 @@ struct rmnet_phys_ep_conf_s {
 	/* MAP specific */
 	uint16_t egress_agg_size;
 	uint16_t egress_agg_count;
+	uint8_t tail_spacing;
+	/* MAP aggregation state machine
+	 *  - This is not sctrictly configuration and is updated at runtime
+	 *    Make sure all of these are protected by the agg_lock
+	 */
 	spinlock_t agg_lock;
 	struct sk_buff *agg_skb;
 	uint8_t agg_state;
 	uint8_t agg_count;
-	uint8_t tail_spacing;
 	struct timespec agg_time;
+	struct timespec agg_last;
 };
 
 int rmnet_config_init(void);
diff --git a/net/rmnet_data/rmnet_data_stats.h b/net/rmnet_data/rmnet_data_stats.h
index e9b2f6c050e9..d5924f1e0768 100644
--- a/net/rmnet_data/rmnet_data_stats.h
+++ b/net/rmnet_data/rmnet_data_stats.h
@@ -48,6 +48,7 @@ enum rmnet_queue_xmit_e {
 	RMNET_STATS_QUEUE_XMIT_AGG_FILL_BUFFER,
 	RMNET_STATS_QUEUE_XMIT_AGG_TIMEOUT,
 	RMNET_STATS_QUEUE_XMIT_AGG_CPY_EXP_FAIL,
+	RMNET_STATS_QUEUE_XMIT_AGG_SKIP,
 	RMNET_STATS_QUEUE_XMIT_MAX
 };
 
diff --git a/net/rmnet_data/rmnet_map_data.c b/net/rmnet_data/rmnet_map_data.c
index 3b3bc20dda87..4691ee5ed805 100644
--- a/net/rmnet_data/rmnet_map_data.c
+++ b/net/rmnet_data/rmnet_map_data.c
@@ -45,6 +45,10 @@ long agg_time_limit __read_mostly = 1000000L;
 module_param(agg_time_limit, long, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(agg_time_limit, "Maximum time packets sit in the agg buf");
 
+long agg_bypass_time __read_mostly = 10000000L;
+module_param(agg_bypass_time, long, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(agg_bypass_time, "Skip agg when apart spaced more than this");
+
 
 struct agg_work {
 	struct delayed_work work;
@@ -225,7 +229,7 @@ void rmnet_map_aggregate(struct sk_buff *skb,
 	struct agg_work *work;
 	unsigned long flags;
 	struct sk_buff *agg_skb;
-	struct timespec t, diff;
+	struct timespec diff, last;
 	int size, rc, agg_count = 0;
 
 
@@ -240,7 +244,28 @@ void rmnet_map_aggregate(struct sk_buff *skb,
 
 new_packet:
 	spin_lock_irqsave(&config->agg_lock, flags);
+
+	memcpy(&last, &(config->agg_last), sizeof(struct timespec));
+	getnstimeofday(&(config->agg_last));
+
 	if (!config->agg_skb) {
+		/* Check to see if we should agg first. If the traffic is very
+		 * sparse, don't aggregate. We will need to tune this later
+		 */
+		diff = timespec_sub(config->agg_last, last);
+
+		if ((diff.tv_sec > 0) || (diff.tv_nsec > agg_bypass_time)) {
+			spin_unlock_irqrestore(&config->agg_lock, flags);
+			LOGL("delta t: %ld.%09lu\tcount: bypass", diff.tv_sec,
+			     diff.tv_nsec);
+			rmnet_stats_agg_pkts(1);
+			trace_rmnet_map_aggregate(skb, 0);
+			rc = dev_queue_xmit(skb);
+			rmnet_stats_queue_xmit(rc,
+					       RMNET_STATS_QUEUE_XMIT_AGG_SKIP);
+			return;
+		}
+
 		config->agg_skb = skb_copy_expand(skb, 0, size, GFP_ATOMIC);
 		if (!config->agg_skb) {
 			config->agg_skb = 0;
@@ -260,8 +285,7 @@ new_packet:
 		rmnet_kfree_skb(skb, RMNET_STATS_SKBFREE_AGG_CPY_EXPAND);
 		goto schedule;
 	}
-	getnstimeofday(&t);
-	diff = timespec_sub(t, config->agg_time);
+	diff = timespec_sub(config->agg_last, config->agg_time);
 
 	if (skb->len > (config->egress_agg_size - config->agg_skb->len)
 	    || (config->agg_count >= config->egress_agg_count)