From d93607082e982223cf92750f2d9039ff365b9d24 Mon Sep 17 00:00:00 2001 From: Heiner Kallweit Date: Wed, 30 Nov 2022 23:28:26 +0100 Subject: [PATCH 1/2] net: add netdev_sw_irq_coalesce_default_on() Add a helper for drivers wanting to set SW IRQ coalescing by default. The related sysfs attributes can be used to override the default values. Follow Jakub's suggestion and put this functionality into net core so that drivers wanting to use software interrupt coalescing per default don't have to open-code it. Note that this function needs to be called before the netdevice is registered. Suggested-by: Jakub Kicinski Signed-off-by: Heiner Kallweit Signed-off-by: David S. Miller --- include/linux/netdevice.h | 1 + net/core/dev.c | 16 ++++++++++++++++ 2 files changed, 17 insertions(+) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 5aa35c58c342b..f78db610ada5f 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -78,6 +78,7 @@ struct xdp_buff; void synchronize_net(void); void netdev_set_default_ethtool_ops(struct net_device *dev, const struct ethtool_ops *ops); +void netdev_sw_irq_coalesce_default_on(struct net_device *dev); /* Backlog congestion levels */ #define NET_RX_SUCCESS 0 /* keep 'em coming, baby */ diff --git a/net/core/dev.c b/net/core/dev.c index 7627c475d991b..b76fb37b381e9 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -10517,6 +10517,22 @@ void netdev_set_default_ethtool_ops(struct net_device *dev, } EXPORT_SYMBOL_GPL(netdev_set_default_ethtool_ops); +/** + * netdev_sw_irq_coalesce_default_on() - enable SW IRQ coalescing by default + * @dev: netdev to enable the IRQ coalescing on + * + * Sets a conservative default for SW IRQ coalescing. Users can use + * sysfs attributes to override the default values. + */ +void netdev_sw_irq_coalesce_default_on(struct net_device *dev) +{ + WARN_ON(dev->reg_state == NETREG_REGISTERED); + + dev->gro_flush_timeout = 20000; + dev->napi_defer_hard_irqs = 1; +} +EXPORT_SYMBOL_GPL(netdev_sw_irq_coalesce_default_on); + void netdev_freemem(struct net_device *dev) { char *addr = (char *)dev - dev->padded; From 42f66a44d83715bef810a543dfd66008b883a7a5 Mon Sep 17 00:00:00 2001 From: Heiner Kallweit Date: Wed, 30 Nov 2022 23:30:15 +0100 Subject: [PATCH 2/2] r8169: enable GRO software interrupt coalescing per default There are reports about r8169 not reaching full line speed on certain systems (e.g. SBC's) with a 2.5Gbps link. There was a time when hardware interrupt coalescing was enabled per default, but this was changed due to ASPM-related issues on few systems. So let's use software interrupt coalescing instead and enable it using new function netdev_sw_irq_coalesce_default_on(). Even with these conservative settings interrupt load on my 1Gbps test system reduced significantly. Signed-off-by: Heiner Kallweit Signed-off-by: David S. Miller --- drivers/net/ethernet/realtek/r8169_main.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c index ec157885da13c..a9dcc98b6af18 100644 --- a/drivers/net/ethernet/realtek/r8169_main.c +++ b/drivers/net/ethernet/realtek/r8169_main.c @@ -5283,6 +5283,8 @@ static int rtl_init_one(struct pci_dev *pdev, const struct pci_device_id *ent) dev->hw_features |= NETIF_F_RXALL; dev->hw_features |= NETIF_F_RXFCS; + netdev_sw_irq_coalesce_default_on(dev); + /* configure chip for default features */ rtl8169_set_features(dev, dev->features);