Commit 28464ef6 authored Dec 14, 2017 by Subash Abhinov Kasiviswanathan

net: qualcomm: rmnet: Set pacing shift



The real device over which the rmnet devices are installed also
aggregate multiple IP packets and sends them as a single large
aggregate frame to the hardware. This causes degraded throughput
for TCP TX due to bufferbloat.

To overcome this problem, pacing shift value of 8 is set using the
sk_pacing_shift_update() helper. This value was determined based
on experiments with a single stream TCP TX using iperf for a
duration of 30s.

Pacing shift | Observed data rate (Mbps)
          10 | 9
           9 | 140
           8 | 146 (Max link rate)

CRs-Fixed: 2156182
Change-Id: I911bf2c26704458f752c79d301ca561fe7f1ffd7
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>

parent 0812cb18

drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -16,6 +16,7 @@
		#include <linux/netdevice.h>
		#include <linux/netdev_features.h>
		#include <linux/if_arp.h>
		#include <net/sock.h>
		#include "rmnet_private.h"
		#include "rmnet_config.h"
		#include "rmnet_vnd.h"
		@@ -204,6 +205,8 @@ void rmnet_egress_handler(struct sk_buff *skb)
		struct rmnet_priv *priv;
		u8 mux_id;

		sk_pacing_shift_update(skb->sk, 8);

		orig_dev = skb->dev;
		priv = netdev_priv(orig_dev);
		skb->dev = priv->real_dev;