On Thu, 17 Nov 2016 13:44:02 -0800 Eric Dumazet <eric.duma...@gmail.com> wrote:
> On Thu, 2016-11-17 at 22:19 +0100, Jesper Dangaard Brouer wrote: > > > > > Maybe you can share your udp flood "udpsnd" program source? > > Very ugly. This is based on what I wrote when tracking the UDP v6 > checksum bug (4f2e4ad56a65f3b7d64c258e373cb71e8d2499f4 net: mangle zero > checksum in skb_checksum_help()), because netperf sends the same message > over and over... Thanks a lot, hope you don't mind; I added the code to my github repo: https://github.com/netoptimizer/network-testing/blob/master/src/udp_snd.c So I identified the difference, and reason behind the route lookups. Your program is using send() and I was using sendmsg(). Given udp_flood is designed to test different calls, I simply added --send as a new possibility. https://github.com/netoptimizer/network-testing/commit/16166c2cd1fa8 If I use --write instead, then I can also avoid the fib_table_lookup and __ip_route_output_key_hash calls. > Use -d 2 to remove the ip_idents_reserve() overhead. #define IP_PMTUDISC_DO 2 /* Always DF */ Added a --pmtu option to my udp_flood program https://github.com/netoptimizer/network-testing/commit/23a78caf4bb5b > #define _GNU_SOURCE > > #include <errno.h> > #include <error.h> > #include <linux/errqueue.h> > #include <netinet/in.h> > #include <sched.h> > #include <stdio.h> > #include <stdlib.h> > #include <string.h> > #include <sys/time.h> > #include <sys/types.h> > #include <sys/socket.h> > #include <unistd.h> > > char buffer[1400]; > > int main(int argc, char** argv) { > int fd, i; > struct sockaddr_in6 addr; > char *host = "2002:af6:798::1"; > int family = AF_INET6; > int discover = -1; > > while ((i = getopt(argc, argv, "4H:d:")) != -1) { > switch (i) { > case 'H': host = optarg; break; > case '4': family = AF_INET; break; > case 'd': discover = atoi(optarg); break; > } > } > fd = socket(family, SOCK_DGRAM, 0); > if (fd < 0) > error(1, errno, "failed to create socket"); > if (discover != -1) > setsockopt(fd, SOL_IP, IP_MTU_DISCOVER, > &discover, sizeof(discover)); > > memset(&addr, 0, sizeof(addr)); > if (family == AF_INET6) { > addr.sin6_family = AF_INET6; > addr.sin6_port = htons(9); > inet_pton(family, host, (void *)&addr.sin6_addr.s6_addr); > } else { > struct sockaddr_in *in = (struct sockaddr_in *)&addr; > in->sin_family = family; > in->sin_port = htons(9); > inet_pton(family, host, &in->sin_addr); > } > connect(fd, (struct sockaddr *)&addr, > (family == AF_INET6) ? sizeof(addr) : > sizeof(struct sockaddr_in)); > memset(buffer, 1, 1400); > for (i = 0; i < 655360000; i++) { > memcpy(buffer, &i, sizeof(i)); > send(fd, buffer, 100 + rand() % 200, 0); Using send() avoids the fib_table_lookup, on a connected UDP socket. > } > return 0; > } -- 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