diff options
| -rw-r--r-- | samples/bpf/xdp_redirect_cpu_user.c | 22 |
1 files changed, 16 insertions, 6 deletions
diff --git a/samples/bpf/xdp_redirect_cpu_user.c b/samples/bpf/xdp_redirect_cpu_user.c index 576411612523..d3ecdc18b9c1 100644 --- a/samples/bpf/xdp_redirect_cpu_user.c +++ b/samples/bpf/xdp_redirect_cpu_user.c @@ -792,13 +792,23 @@ int main(int argc, char **argv) n_cpus = get_nprocs_conf(); - /* Notice: choosing he queue size is very important with the - * ixgbe driver, because it's driver page recycling trick is - * dependend on pages being returned quickly. The number of - * out-standing packets in the system must be less-than 2x - * RX-ring size. + /* Notice: Choosing the queue size is very important when CPU is + * configured with power-saving states. + * + * If deepest state take 133 usec to wakeup from (133/10^6). When link + * speed is 10Gbit/s ((10*10^9/8) in bytes/sec). How many bytes can + * arrive with in 133 usec at this speed: (10*10^9/8)*(133/10^6) = + * 166250 bytes. With MTU size packets this is 110 packets, and with + * minimum Ethernet (MAC-preamble + intergap) 84 bytes is 1979 packets. + * + * Setting default cpumap queue to 2048 as worst-case (small packet) + * should be +64 packet due kthread wakeup call (due to xdp_do_flush) + * worst-case is 2043 packets. + * + * Sysadm can configured system to avoid deep-sleep via: + * tuned-adm profile network-latency */ - qsize = 128+64; + qsize = 2048; snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); prog_load_attr.file = filename; |