I'm using banana pi device with openwrt.
It was running DESIGNATED DRIVER (Bleeding Edge, r48830) since 2016. Everything was mostly fine except for stmmac driver that crashed on jumboframes.
Yesterday I decided to upgrade to the latest lede (now openwrt again) build.
Now on the same workload kernel cpu usage is higher by 30..40%, maximum speeds are lower.
OLD kernel 4.4.3
5.07% [ip_tables] [k] ipt_do_table
1.65% [kernel] [k] csum_partial
1.62% [kernel] [k] stmmac_poll
1.58% [kernel] [k] _raw_spin_unlock_irqrestore
1.36% [kernel] [k] __netif_receive_skb_core
1.30% [kernel] [k] stmmac_xmit
1.27% [sch_htb] [k] htb_dequeue
1.26% [kernel] [k] __dev_queue_xmit
1.25% [kernel] [k] ndesc_get_rx_status
1.19% [nf_conntrack] [k] __nf_conntrack_find_get
1.08% [kernel] [k] net_rx_action
1.05% [kernel] [k] __do_softirq
0.88% [kernel] [k] dev_gro_receive
0.88% [kernel] [k] ip_forward
0.86% [kernel] [k] _raw_spin_unlock_irq
0.84% [kernel] [k] kmem_cache_alloc
0.81% [kernel] [k] netif_skb_features
0.81% [xt_conntrack] [k] conntrack_mt
0.80% [kernel] [k] ndesc_get_tx_status
0.77% [kernel] [k] csum_partial_copy_nocheck
NEW kernel 4.9.75
6.08% [kernel] [k] __slab_alloc.constprop.7
3.64% [kernel] [k] _raw_spin_unlock_irqrestore
2.57% [kernel] [k] __usb_hcd_giveback_urb
2.04% [ip_tables] [k] ipt_do_table
1.27% [kernel] [k] __do_softirq
0.93% [kernel] [k] stmmac_poll
0.81% [kernel] [k] net_rx_action
0.68% [kernel] [k] stmmac_xmit
0.64% [kernel] [k] _raw_spin_unlock_irq
0.62% [kernel] [k] __dev_queue_xmit
0.58% [kernel] [k] csum_partial
0.53% libc.so [.] 0x00029b18
0.50% perf [.] 0x000bd69c
0.48% [kernel] [k] __netif_receive_skb_core
0.47% [kernel] [k] nf_iterate
0.47% [kernel] [k] __skb_flow_dissect
0.46% [nf_conntrack] [k] __nf_conntrack_find_get
0.44% [kernel] [k] csum_partial_copy_nocheck
0.43% [kernel] [k] dev_gro_receive
0.42% [kernel] [k] __memzero
These functions take much cpu time
6.08% [kernel] [k] __slab_alloc.constprop.7
3.64% [kernel] [k] _raw_spin_unlock_irqrestore
and performance is slow. Had to revert back
So i'm asking is it caused by updated stmmac driver or may be changes in kernel.
Any ideas, workarounds ?
this device acts as VLAN router. It routes 100 mbit eth0.1 to eth0.2 with duplex mode. Physical eth0 uploads and downloads up to 200 mbit simultaneously