On 09/27/2017 02:26 AM, Jesper Dangaard Brouer wrote: > On Tue, 26 Sep 2017 21:58:53 +0200 > Daniel Borkmann <dan...@iogearbox.net> wrote: > >> On 09/26/2017 09:13 PM, Jesper Dangaard Brouer wrote: >> [...] >>> I'm currently implementing a cpumap type, that transfers raw XDP frames >>> to another CPU, and the SKB is allocated on the remote CPU. (It >>> actually works extremely well). >> >> Meaning you let all the XDP_PASS packets get processed on a >> different CPU, so you can reserve the whole CPU just for >> prefiltering, right? > > Yes, exactly. Except I use the XDP_REDIRECT action to steer packets. > The trick is using the map-flush point, to transfer packets in bulk to > the remote CPU (single call IPC is too slow), but at the same time > flush single packets if NAPI didn't see a bulk. > >> Do you have some numbers to share at this point, just curious when >> you mention it works extremely well. > > Sure... I've done a lot of benchmarking on this patchset ;-) > I have a benchmark program called xdp_redirect_cpu [1][2], that collect > stats via tracepoints (atm I'm limiting bulking 8 packets, and have > tracepoints at bulk spots, to amortize tracepoint cost 25ns/8=3.125ns) > > [1] > https://github.com/netoptimizer/prototype-kernel/blob/master/kernel/samples/bpf/xdp_redirect_cpu_kern.c > [2] > https://github.com/netoptimizer/prototype-kernel/blob/master/kernel/samples/bpf/xdp_redirect_cpu_user.c > > Here I'm installing a DDoS program that drops UDP port 9 (pktgen > packets) on RX CPU=0. I'm forcing my netperf to hit the same CPU, that > the 11.9Mpps DDoS attack is hitting. > > Running XDP/eBPF prog_num:4 > XDP-cpumap CPU:to pps drop-pps extra-info > XDP-RX 0 12,030,471 11,966,982 0 > XDP-RX total 12,030,471 11,966,982 > cpumap-enqueue 0:2 63,488 0 0 > cpumap-enqueue sum:2 63,488 0 0 > cpumap_kthread 2 63,488 0 3 time_exceed > cpumap_kthread total 63,488 0 0 > redirect_err total 0 0 > > $ netperf -H 172.16.0.2 -t TCP_CRR -l 10 -D1 -T5,5 -- -r 1024,1024 > Local /Remote > Socket Size Request Resp. Elapsed Trans. > Send Recv Size Size Time Rate > bytes Bytes bytes bytes secs. per sec > > 16384 87380 1024 1024 10.00 12735.97 > 16384 87380 > > The netperf TCP_CRR performance is the same, without XDP loaded. >
Just curious could you also try this with RPS enabled (or does this have RPS enabled). RPS should effectively do the same thing but higher in the stack. I'm curious what the delta would be. Might be another interesting case and fairly easy to setup if you already have the above scripts. Thanks, John [...]
