I'm testing with this program and these patches, after getting past the challenge of compiling the samples/bpf files ;-)
On Fri, 1 Apr 2016 18:21:58 -0700 Brenden Blanco <bbla...@plumgrid.com> wrote: > Add a sample program that only drops packets at the > BPF_PROG_TYPE_PHYS_DEV hook of a link. With the drop-only program, > observed single core rate is ~14.6Mpps. On my i7-4790K CPU @ 4.00GHz I'm seeing 9.7Mpps (single flow/cpu). (generator: pktgen_sample03_burst_single_flow.sh) # ./netdrvx1 $(</sys/class/net/mlx4p1/ifindex) sh: /sys/kernel/debug/tracing/kprobe_events: No such file or directory Success: Loaded file ./netdrvx1_kern.o proto 17: 9776320 drops/s These numbers are quite impressive. Compared to: sending it to local socket that drop packets 1.7Mpps. Compared to: dropping with iptables in "raw" table 3.7Mpps. If I do multiple flows, via ./pktgen_sample05_flow_per_thread.sh then I hit this strange 14.5Mpps limit (proto 17: 14505558 drops/s). And the RX 4x CPUs are starting to NOT use 100% in softirq, they have some cycles attributed to %idle. (I verified generator is sending at 24Mpps). > Other tests were run, for instance without the dropcnt increment or > without reading from the packet header, the packet rate was mostly > unchanged. If I change the program to not touch packet data (don't call load_byte()) then the performance increase to 14.6Mpps (single flow/cpu). And the RX CPU is mostly idle... mlx4_en_process_rx_cq() and page alloc/free functions taking the time. > $ perf record -a samples/bpf/netdrvx1 $(</sys/class/net/eth0/ifindex) > proto 17: 14597724 drops/s > > ./pktgen_sample03_burst_single_flow.sh -i $DEV -d $IP -m $MAC -t 4 > Running... ctrl^C to stop > Device: eth4@0 > Result: OK: 6486875(c6485849+d1026) usec, 23689465 (60byte,0frags) > 3651906pps 1752Mb/sec (1752914880bps) errors: 0 > Device: eth4@1 > Result: OK: 6486874(c6485656+d1217) usec, 23689489 (60byte,0frags) > 3651911pps 1752Mb/sec (1752917280bps) errors: 0 > Device: eth4@2 > Result: OK: 6486851(c6485730+d1120) usec, 23687853 (60byte,0frags) > 3651672pps 1752Mb/sec (1752802560bps) errors: 0 > Device: eth4@3 > Result: OK: 6486879(c6485807+d1071) usec, 23688954 (60byte,0frags) > 3651825pps 1752Mb/sec (1752876000bps) errors: 0 > > perf report --no-children: > 18.36% ksoftirqd/1 [mlx4_en] [k] mlx4_en_process_rx_cq > 15.98% swapper [kernel.vmlinux] [k] poll_idle > 12.71% ksoftirqd/1 [mlx4_en] [k] mlx4_en_alloc_frags > 6.87% ksoftirqd/1 [mlx4_en] [k] mlx4_en_free_frag > 4.20% ksoftirqd/1 [kernel.vmlinux] [k] get_page_from_freelist > 4.09% swapper [mlx4_en] [k] mlx4_en_process_rx_cq > 3.32% ksoftirqd/1 [kernel.vmlinux] [k] sk_load_byte_positive_offset > 2.39% ksoftirqd/1 [mdio] [k] 0x00000000000074cd > 2.23% swapper [mlx4_en] [k] mlx4_en_alloc_frags > 2.20% ksoftirqd/1 [kernel.vmlinux] [k] free_pages_prepare > 2.08% ksoftirqd/1 [mlx4_en] [k] mlx4_call_bpf > 1.57% ksoftirqd/1 [kernel.vmlinux] [k] percpu_array_map_lookup_elem > 1.35% ksoftirqd/1 [mdio] [k] 0x00000000000074fa > 1.09% ksoftirqd/1 [kernel.vmlinux] [k] free_one_page > 1.02% ksoftirqd/1 [kernel.vmlinux] [k] bpf_map_lookup_elem > 0.90% ksoftirqd/1 [kernel.vmlinux] [k] __alloc_pages_nodemask > 0.88% swapper [kernel.vmlinux] [k] intel_idle > 0.82% ksoftirqd/1 [mdio] [k] 0x00000000000074be > 0.80% swapper [mlx4_en] [k] mlx4_en_free_frag My picture (single flow/cpu) looks a little bit different: + 64.33% ksoftirqd/7 [kernel.vmlinux] [k] __bpf_prog_run + 9.60% ksoftirqd/7 [mlx4_en] [k] mlx4_en_alloc_frags + 7.71% ksoftirqd/7 [mlx4_en] [k] mlx4_en_process_rx_cq + 5.47% ksoftirqd/7 [mlx4_en] [k] mlx4_en_free_frag + 1.68% ksoftirqd/7 [kernel.vmlinux] [k] get_page_from_freelist + 1.52% ksoftirqd/7 [mlx4_en] [k] mlx4_call_bpf + 1.02% ksoftirqd/7 [kernel.vmlinux] [k] free_pages_prepare + 0.72% ksoftirqd/7 [mlx4_en] [k] mlx4_alloc_pages.isra.20 + 0.70% ksoftirqd/7 [kernel.vmlinux] [k] __rcu_read_unlock + 0.65% ksoftirqd/7 [kernel.vmlinux] [k] percpu_array_map_lookup_elem On my i7-4790K CPU, I don't have DDIO, thus I assume this high cost in __bpf_prog_run is due to a cache-miss on the packet data. > machine specs: > receiver - Intel E5-1630 v3 @ 3.70GHz > sender - Intel E5645 @ 2.40GHz > Mellanox ConnectX-3 @40G -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat Author of http://www.iptv-analyzer.org LinkedIn: http://www.linkedin.com/in/brouer
