2013/8/11 Rafał Miłecki <zaj...@gmail.com>: > It makes more sense to allocate new (empty) skb and pass it to the > hardware. That way we avoid copying whole packet into new skb which > should result in better performance.
I did some testing of this patch using "perf" tool and iperf -s running on the OpenWrt machine (with bgmac supported hardware). There are the results: No network usage: 64.93% [kernel] [k] arch_cpu_idle 16.10% [kernel] [k] arch_local_irq_restore 11.52% [kernel] [k] cpu_startup_entry Running iperf on PC: iperf -c 192.168.1.1 23.57% [kernel] [k] __copy_user_common 10.57% [kernel] [k] csum_partial 8.87% [kernel] [k] arch_cpu_idle 4.74% [kernel] [k] arch_local_irq_restore 4.30% [ip_tables] [k] ipt_do_table 2.91% [nf_conntrack] [k] nf_conntrack_in 2.44% [kernel] [k] __netif_receive_skb_core 2.36% [kernel] [k] r4k_dma_cache_inv 2.33% [nf_conntrack] [k] nf_conntrack_proto_fini With 0002-bgmac-pass-received-packet-to-the-netif-instead-of-c.patch 14.83% [kernel] [k] __copy_user_common 14.81% [kernel] [k] csum_partial 4.24% [ip_tables] [k] ipt_do_table 3.69% [kernel] [k] arch_local_irq_restore 3.54% [kernel] [k] __netif_receive_skb_core 3.38% [kernel] [k] r4k_dma_cache_inv 3.24% [nf_conntrack] [k] nf_conntrack_in 2.95% [xt_conntrack] [k] 0x0000018c 2.88% [nf_conntrack] [k] nf_conntrack_proto_fini 2.58% [iptable_nat] [k] 0x00000008 2.32% [bgmac] [k] 0x00000d9c 2.18% [nf_conntrack_ipv4] [k] need_ipv4_conntrack So you can see that __copy_user_common usage has really decreased with this patch! Unfortunately it didn't result in better performance... no idea why :( -- Rafał _______________________________________________ openwrt-devel mailing list openwrt-devel@lists.openwrt.org https://lists.openwrt.org/cgi-bin/mailman/listinfo/openwrt-devel
