From 38b50dba4704856194ac02b98e492d2349d64058 Mon Sep 17 00:00:00 2001 From: Stefano Brivio Date: Fri, 23 Apr 2021 22:22:37 +0200 Subject: passt: Spare some syscalls, add some optimisations from profiling Avoid a bunch of syscalls on forwarding paths by: - storing minimum and maximum file descriptor numbers for each protocol, fall back to SO_PROTOCOL query only on overlaps - allocating a larger receive buffer -- this can result in more coalesced packets than sendmmsg() can take (UIO_MAXIOV, i.e. 1024), so make sure we don't exceed that within a single call to protocol tap handlers - nesting the handling loop in tap_handler() in the receive loop, so that we have better chances of filling our receive buffer in fewer calls - skipping the recvfrom() in the UDP handler on EPOLLERR -- there's nothing to be done in that case and while at it: - restore the 20ms timer interval for periodic (TCP) events, I accidentally changed that to 100ms in an earlier commit - attempt using SO_ZEROCOPY for UDP -- if it's not available, sendmmsg() will succeed anyway - fix the handling of the status code from sendmmsg(), if it fails, we'll try to discard the first message, hence return 1 from the UDP handler Signed-off-by: Stefano Brivio --- util.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'util.c') diff --git a/util.c b/util.c index 7a75e02..cc96a1a 100644 --- a/util.c +++ b/util.c @@ -189,6 +189,21 @@ int sock_l4_add(struct ctx *c, int v, uint16_t proto, uint16_t port) return -1; } +#define CHECK_SET_MIN_MAX(ipproto, proto_ctx, fd) \ + if (proto == (ipproto)) { \ + if (fd < c->proto_ctx.fd_min) \ + c->proto_ctx.fd_min = (fd); \ + if (fd > c->proto_ctx.fd_max) \ + c->proto_ctx.fd_max = (fd); \ + } + + CHECK_SET_MIN_MAX(IPPROTO_ICMP, icmp, fd); + CHECK_SET_MIN_MAX(IPPROTO_ICMPV6, icmp, fd); + CHECK_SET_MIN_MAX(IPPROTO_TCP, tcp, fd); + CHECK_SET_MIN_MAX(IPPROTO_UDP, udp, fd); + +#undef CHECK_SET_MIN_MAX + if (proto == IPPROTO_ICMP || proto == IPPROTO_ICMPV6) goto epoll_add; -- cgit v1.2.3