From a0783cd0c810504427777e8aae20d5f4f8b652a0 Mon Sep 17 00:00:00 2001
From: Corinna Vinschen <vinschen@redhat.com>
Date: Tue, 19 Nov 2019 10:09:39 +0100
Subject: [PATCH] r8169: disable TSO on a single version of RTL8168c to fix performance
Git-commit: a0783cd0c810504427777e8aae20d5f4f8b652a0
Patch-mainline: v5.4
References: bsc#1175746
During performance testing, I found that one of my r8169 NICs suffered
a major performance loss, a 8168c model.
Running netperf's TCP_STREAM test didn't return the expected
throughput of > 900 Mb/s, but rather only about 22 Mb/s. Strange
enough, running the TCP_MAERTS and UDP_STREAM tests all returned with
throughput > 900 Mb/s, as did TCP_STREAM with the other r8169 NICs I can
test (either one of 8169s, 8168e, 8168f).
Bisecting turned up commit 93681cd7d94f83903cb3f0f95433d10c28a7e9a5,
"r8169: enable HW csum and TSO" as the culprit.
I added my 8168c version, RTL_GIGA_MAC_VER_22, to the code
special-casing the 8168evl as per the patch below. This fixed the
performance problem for me.
Fixes: 93681cd7d94f ("r8169: enable HW csum and TSO")
Signed-off-by: Corinna Vinschen <vinschen@redhat.com>
Reviewed-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/net/ethernet/realtek/r8169_main.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c
index c4e961ea44d5..c33c438850cc 100644
--- a/drivers/net/ethernet/realtek/r8169_main.c
+++ b/drivers/net/ethernet/realtek/r8169_main.c
@@ -7179,8 +7179,11 @@ static int rtl_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
dev->gso_max_segs = RTL_GSO_MAX_SEGS_V1;
}
- /* RTL8168e-vl has a HW issue with TSO */
- if (tp->mac_version == RTL_GIGA_MAC_VER_34) {
+ /* RTL8168e-vl and one RTL8168c variant are known to have a
+ * HW issue with TSO.
+ */
+ if (tp->mac_version == RTL_GIGA_MAC_VER_34 ||
+ tp->mac_version == RTL_GIGA_MAC_VER_22) {
dev->vlan_features &= ~(NETIF_F_ALL_TSO | NETIF_F_SG);
dev->hw_features &= ~(NETIF_F_ALL_TSO | NETIF_F_SG);
dev->features &= ~(NETIF_F_ALL_TSO | NETIF_F_SG);
--
2.16.4