[PATCH v2 net-next 1/2] net: mana: Allow tso_max_size to go up-to GSO_MAX_SIZE

[Shradha Gupta <shradhagupta@linux.microsoft.com>]

Allow the max aggregated pkt size to go up-to GSO_MAX_SIZE for MANA NIC.
This patch only increases the max allowable gso/gro pkt size for MANA
devices and does not change the defaults.
Following are the perf benefits by increasing the pkt aggregate size from
legacy gso_max_size value(64K) to newer one(up-to 511K)

for i in {1..10}; do netperf -t TCP_RR  -H 10.0.0.5 -p50000 -- -r80000,80000
-O MIN_LATENCY,P90_LATENCY,P99_LATENCY,THROUGHPUT|tail -1; done

min	p90	p99	Throughput		gso_max_size
93	171	194	6594.25
97	154	180	7183.74
95	165	189	6927.86
96	165	188	6976.04
93	154	185	7338.05			64K
93	168	189	6938.03
94	169	189	6784.93
92	166	189	7117.56
94	179	191	6678.44
95	157	183	7277.81

min	p90	p99	Throughput
93	134	146	8448.75
95	134	140	8396.54
94	137	148	8204.12
94	137	148	8244.41
94	128	139	8666.52			80K
94	141	153	8116.86
94	138	149	8163.92
92	135	142	8362.72
92	134	142	8497.57
93	136	148	8393.23

Tested on azure env with Accelerated Networking enabled and disabled.

Signed-off-by: Shradha Gupta <shradhagupta@linux.microsoft.com>
---
 Changes in v2
 * Instead of using 'tcp segment' throughout the patch used used more accurate
   term 'aggregated pkt size'
---
 drivers/net/ethernet/microsoft/mana/mana_en.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/ethernet/microsoft/mana/mana_en.c b/drivers/net/ethernet/microsoft/mana/mana_en.c
index aa1e47233fe5..da630cb37cfb 100644
--- a/drivers/net/ethernet/microsoft/mana/mana_en.c
+++ b/drivers/net/ethernet/microsoft/mana/mana_en.c
@@ -2873,6 +2873,8 @@ static int mana_probe_port(struct mana_context *ac, int port_idx,
 	ndev->dev_port = port_idx;
 	SET_NETDEV_DEV(ndev, gc->dev);
 
+	netif_set_tso_max_size(ndev, GSO_MAX_SIZE);
+
 	netif_carrier_off(ndev);
 
 	netdev_rss_key_fill(apc->hashkey, MANA_HASH_KEY_SIZE);
-- 
2.34.1