Jesper Dangaard Brouer fad3917e36 samples/bpf: add cpumap sample program xdp_redirect_cpu ... This sample program show how to use cpumap and the associated tracepoints. It provides command line stats, which shows how the XDP-RX process, cpumap-enqueue and cpumap kthread dequeue is cooperating on a per CPU basis. It also utilize the xdp_exception and xdp_redirect_err transpoints to allow users quickly to identify setup issues. One issue with ixgbe driver is that the driver reset the link when loading XDP. This reset the procfs smp_affinity settings. Thus, after loading the program, these must be reconfigured. The easiest workaround it to reduce the RX-queue to e.g. two via: # ethtool --set-channels ixgbe1 combined 2 And then add CPUs above 0 and 1, like: # xdp_redirect_cpu --dev ixgbe1 --prog 2 --cpu 2 --cpu 3 --cpu 4 Another issue with ixgbe is that the page recycle mechanism is tied to the RX-ring size. And the default setting of 512 elements is too small. This is the same issue with regular devmap XDP_REDIRECT. To overcome this I've been using 1024 rx-ring size: # ethtool -G ixgbe1 rx 1024 tx 1024 V3: - whitespace cleanups - bpf tracepoint cannot access top part of struct V4: - report on kthread sched events, according to tracepoint change - report average bulk enqueue size V5: - bpf_map_lookup_elem on cpumap not allowed from bpf_prog use separate map to mark CPUs not available V6: - correct kthread sched summary output V7: - Added a --stress-mode for concurrently changing underlying cpumap Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>		2017-10-18 12:12:18 +01:00
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bpf	samples/bpf: add cpumap sample program xdp_redirect_cpu	2017-10-18 12:12:18 +01:00
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