2013/8/15 Felix Fietkau <n...@openwrt.org>: > On 2013-08-15 1:36 PM, Rafał Miłecki wrote: >> 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). >> >> 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 :( > Running iperf on the router is not useful as an indicator of routing > performance. Please focus on tests where you only push traffic through > the router, not directly to it.
OK, so I started "iperf -s" on notebook plugged into WAN port, and then played with "iperf -c" on notebook connected to LAN#2. With some old 3.6.11 based OpenWrt build I got: [ 4] 0.0-60.0 sec 690 MBytes 96.4 Mbits/sec With very recent 3.10.4 based OpenWrt build: [ 4] 0.0-60.0 sec 667 MBytes 93.2 Mbits/sec After applying my patch on top of that 3.10.4: [ 5] 0.0-60.0 sec 759 MBytes 106 Mbits/sec And some dumps from "perf top": 3.10.4 6.75% [kernel] [k] __copy_user_common 6.73% [ip_tables] [k] ipt_do_table 4.33% [kernel] [k] arch_cpu_idle 3.96% [kernel] [k] arch_local_irq_restore 3.42% [bgmac] [k] 0x000007e0 3.35% [nf_conntrack] [k] nf_conntrack_proto_fini 2.72% [nf_conntrack] [k] nf_conntrack_in 2.50% [kernel] [k] __netif_receive_skb_core 2.42% [kernel] [k] r4k_dma_cache_inv 2.38% [kernel] [k] fib_table_lookup 2.20% [kernel] [k] dev_queue_xmit 2.11% [xt_conntrack] [k] 0x00000360 2.10% [kernel] [k] ip_route_input_noref 2.06% [nf_conntrack_ipv4] [k] need_ipv4_conntrack 3.10.4 + 0002-bgmac-pass-received-packet-to-the-netif-instead-of-c.patch 6.09% [ip_tables] [k] ipt_do_table 4.71% [kernel] [k] arch_cpu_idle 4.48% [bgmac] [k] 0x00000d7c 3.50% [nf_conntrack] [k] nf_conntrack_in 3.22% [kernel] [k] arch_local_irq_restore 3.16% [nf_conntrack] [k] nf_conntrack_proto_fini 2.88% [kernel] [k] __netif_receive_skb_core 2.78% [xt_conntrack] [k] 0x0000011c 2.69% [kernel] [k] r4k_dma_cache_inv 2.67% [iptable_nat] [k] 0x000002a0 2.36% [kernel] [k] ip_route_input_noref 2.27% [kernel] [k] ip_rcv 2.25% [nf_conntrack_ipv4] [k] need_ipv4_conntrack 2.23% [kernel] [k] nf_iterate I've compiled bgmac into the kernel and it seems that the magic 0xd7c was bgmac_poll. I'm afraid this "perf top" output doesn't really tell us where to look for optimizations :| I'll still try Felix ideas tomorrow, but I'm not sure if they help, since there isn't __copy_user_common anymore in the "perf top" output... -- Rafał _______________________________________________ openwrt-devel mailing list openwrt-devel@lists.openwrt.org https://lists.openwrt.org/cgi-bin/mailman/listinfo/openwrt-devel
