From 04b1440d3381fda5f7c970b65c96447cb2f9af41 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?fengbojiang=28=E5=A7=9C=E5=87=A4=E6=B3=A2=29?= Date: Fri, 22 Nov 2019 11:40:45 +0800 Subject: [PATCH] The TCP stack has been changed to use the estimated RTT instead of timestamps for receive buffer auto resizing. Corresponding upstream changeset from https://svnweb.freebsd.org/base?view=revision&revision=317368. --- freebsd/netinet/in_kdtrace.c | 8 ++ freebsd/netinet/in_kdtrace.h | 1 + freebsd/netinet/tcp_input.c | 123 +++++++++++++------------- freebsd/netinet/tcp_output.c | 10 ++- freebsd/netinet/tcp_stacks/fastpath.c | 62 +------------ freebsd/netinet/tcp_var.h | 2 + 6 files changed, 82 insertions(+), 124 deletions(-) diff --git a/freebsd/netinet/in_kdtrace.c b/freebsd/netinet/in_kdtrace.c index 0efe40371..f46f741c8 100644 --- a/freebsd/netinet/in_kdtrace.c +++ b/freebsd/netinet/in_kdtrace.c @@ -132,6 +132,14 @@ SDT_PROBE_DEFINE6_XLATE(tcp, , , state__change, "void *", "void *", "int", "tcplsinfo_t *"); +SDT_PROBE_DEFINE6_XLATE(tcp, , , receive__autoresize, + "void *", "void *", + "struct tcpcb *", "csinfo_t *", + "struct mbuf *", "ipinfo_t *", + "struct tcpcb *", "tcpsinfo_t *" , + "struct tcphdr *", "tcpinfoh_t *", + "int", "int"); + SDT_PROBE_DEFINE5_XLATE(udp, , , receive, "void *", "pktinfo_t *", "struct inpcb *", "csinfo_t *", diff --git a/freebsd/netinet/in_kdtrace.h b/freebsd/netinet/in_kdtrace.h index a36991ef1..0825c7dff 100644 --- a/freebsd/netinet/in_kdtrace.h +++ b/freebsd/netinet/in_kdtrace.h @@ -65,6 +65,7 @@ SDT_PROBE_DECLARE(tcp, , , debug__input); SDT_PROBE_DECLARE(tcp, , , debug__output); SDT_PROBE_DECLARE(tcp, , , debug__user); SDT_PROBE_DECLARE(tcp, , , debug__drop); +SDT_PROBE_DECLARE(tcp, , , receive__autoresize); SDT_PROBE_DECLARE(udp, , , receive); SDT_PROBE_DECLARE(udp, , , send); diff --git a/freebsd/netinet/tcp_input.c b/freebsd/netinet/tcp_input.c index c72f01fa4..ed05fa1a6 100644 --- a/freebsd/netinet/tcp_input.c +++ b/freebsd/netinet/tcp_input.c @@ -1494,6 +1494,68 @@ drop: return (IPPROTO_DONE); } +/* + * Automatic sizing of receive socket buffer. Often the send + * buffer size is not optimally adjusted to the actual network + * conditions at hand (delay bandwidth product). Setting the + * buffer size too small limits throughput on links with high + * bandwidth and high delay (eg. trans-continental/oceanic links). + * + * On the receive side the socket buffer memory is only rarely + * used to any significant extent. This allows us to be much + * more aggressive in scaling the receive socket buffer. For + * the case that the buffer space is actually used to a large + * extent and we run out of kernel memory we can simply drop + * the new segments; TCP on the sender will just retransmit it + * later. Setting the buffer size too big may only consume too + * much kernel memory if the application doesn't read() from + * the socket or packet loss or reordering makes use of the + * reassembly queue. + * + * The criteria to step up the receive buffer one notch are: + * 1. Application has not set receive buffer size with + * SO_RCVBUF. Setting SO_RCVBUF clears SB_AUTOSIZE. + * 2. the number of bytes received during the time it takes + * one timestamp to be reflected back to us (the RTT); + * 3. received bytes per RTT is within seven eighth of the + * current socket buffer size; + * 4. receive buffer size has not hit maximal automatic size; + * + * This algorithm does one step per RTT at most and only if + * we receive a bulk stream w/o packet losses or reorderings. + * Shrinking the buffer during idle times is not necessary as + * it doesn't consume any memory when idle. + * + * TODO: Only step up if the application is actually serving + * the buffer to better manage the socket buffer resources. + */ +int +tcp_autorcvbuf(struct mbuf *m, struct tcphdr *th, struct socket *so, + struct tcpcb *tp, int tlen) +{ + int newsize = 0; + + if (V_tcp_do_autorcvbuf && (so->so_rcv.sb_flags & SB_AUTOSIZE) && + tp->t_srtt != 0 && tp->rfbuf_ts != 0 && + TCP_TS_TO_TICKS(tcp_ts_getticks() - tp->rfbuf_ts) > + (tp->t_srtt >> TCP_RTT_SHIFT)) { + if (tp->rfbuf_cnt > (so->so_rcv.sb_hiwat / 8 * 7) && + so->so_rcv.sb_hiwat < V_tcp_autorcvbuf_max) { + newsize = min(so->so_rcv.sb_hiwat + + V_tcp_autorcvbuf_inc, V_tcp_autorcvbuf_max); + } + TCP_PROBE6(receive__autoresize, NULL, tp, m, tp, th, newsize); + + /* Start over with next RTT. */ + tp->rfbuf_ts = 0; + tp->rfbuf_cnt = 0; + } else { + tp->rfbuf_cnt += tlen; /* add up */ + } + + return (newsize); +} + void tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so, struct tcpcb *tp, int drop_hdrlen, int tlen, uint8_t iptos, @@ -1847,62 +1909,7 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so, #endif TCP_PROBE3(debug__input, tp, th, mtod(m, const char *)); - /* - * Automatic sizing of receive socket buffer. Often the send - * buffer size is not optimally adjusted to the actual network - * conditions at hand (delay bandwidth product). Setting the - * buffer size too small limits throughput on links with high - * bandwidth and high delay (eg. trans-continental/oceanic links). - * - * On the receive side the socket buffer memory is only rarely - * used to any significant extent. This allows us to be much - * more aggressive in scaling the receive socket buffer. For - * the case that the buffer space is actually used to a large - * extent and we run out of kernel memory we can simply drop - * the new segments; TCP on the sender will just retransmit it - * later. Setting the buffer size too big may only consume too - * much kernel memory if the application doesn't read() from - * the socket or packet loss or reordering makes use of the - * reassembly queue. - * - * The criteria to step up the receive buffer one notch are: - * 1. Application has not set receive buffer size with - * SO_RCVBUF. Setting SO_RCVBUF clears SB_AUTOSIZE. - * 2. the number of bytes received during the time it takes - * one timestamp to be reflected back to us (the RTT); - * 3. received bytes per RTT is within seven eighth of the - * current socket buffer size; - * 4. receive buffer size has not hit maximal automatic size; - * - * This algorithm does one step per RTT at most and only if - * we receive a bulk stream w/o packet losses or reorderings. - * Shrinking the buffer during idle times is not necessary as - * it doesn't consume any memory when idle. - * - * TODO: Only step up if the application is actually serving - * the buffer to better manage the socket buffer resources. - */ - if (V_tcp_do_autorcvbuf && - (to.to_flags & TOF_TS) && - to.to_tsecr && - (so->so_rcv.sb_flags & SB_AUTOSIZE)) { - if (TSTMP_GT(to.to_tsecr, tp->rfbuf_ts) && - to.to_tsecr - tp->rfbuf_ts < hz) { - if (tp->rfbuf_cnt > - (so->so_rcv.sb_hiwat / 8 * 7) && - so->so_rcv.sb_hiwat < - V_tcp_autorcvbuf_max) { - newsize = - min(so->so_rcv.sb_hiwat + - V_tcp_autorcvbuf_inc, - V_tcp_autorcvbuf_max); - } - /* Start over with next RTT. */ - tp->rfbuf_ts = 0; - tp->rfbuf_cnt = 0; - } else - tp->rfbuf_cnt += tlen; /* add up */ - } + newsize = tcp_autorcvbuf(m, th, so, tp, tlen); /* Add data to socket buffer. */ SOCKBUF_LOCK(&so->so_rcv); @@ -1943,10 +1950,6 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so, win = 0; tp->rcv_wnd = imax(win, (int)(tp->rcv_adv - tp->rcv_nxt)); - /* Reset receive buffer auto scaling when not in bulk receive mode. */ - tp->rfbuf_ts = 0; - tp->rfbuf_cnt = 0; - switch (tp->t_state) { /* diff --git a/freebsd/netinet/tcp_output.c b/freebsd/netinet/tcp_output.c index e1d9488a7..a70a2d72b 100644 --- a/freebsd/netinet/tcp_output.c +++ b/freebsd/netinet/tcp_output.c @@ -798,11 +798,13 @@ send: to.to_tsval = tcp_ts_getticks() + tp->ts_offset; to.to_tsecr = tp->ts_recent; to.to_flags |= TOF_TS; - /* Set receive buffer autosizing timestamp. */ - if (tp->rfbuf_ts == 0 && - (so->so_rcv.sb_flags & SB_AUTOSIZE)) - tp->rfbuf_ts = tcp_ts_getticks(); } + + /* Set receive buffer autosizing timestamp. */ + if (tp->rfbuf_ts == 0 && + (so->so_rcv.sb_flags & SB_AUTOSIZE)) + tp->rfbuf_ts = tcp_ts_getticks(); + /* Selective ACK's. */ if (tp->t_flags & TF_SACK_PERMIT) { if (flags & TH_SYN) diff --git a/freebsd/netinet/tcp_stacks/fastpath.c b/freebsd/netinet/tcp_stacks/fastpath.c index 7be9f9681..403e52c59 100644 --- a/freebsd/netinet/tcp_stacks/fastpath.c +++ b/freebsd/netinet/tcp_stacks/fastpath.c @@ -396,62 +396,8 @@ tcp_do_fastnewdata(struct mbuf *m, struct tcphdr *th, struct socket *so, (void *)tcp_saveipgen, &tcp_savetcp, 0); #endif TCP_PROBE3(debug__input, tp, th, mtod(m, const char *)); - /* - * Automatic sizing of receive socket buffer. Often the send - * buffer size is not optimally adjusted to the actual network - * conditions at hand (delay bandwidth product). Setting the - * buffer size too small limits throughput on links with high - * bandwidth and high delay (eg. trans-continental/oceanic links). - * - * On the receive side the socket buffer memory is only rarely - * used to any significant extent. This allows us to be much - * more aggressive in scaling the receive socket buffer. For - * the case that the buffer space is actually used to a large - * extent and we run out of kernel memory we can simply drop - * the new segments; TCP on the sender will just retransmit it - * later. Setting the buffer size too big may only consume too - * much kernel memory if the application doesn't read() from - * the socket or packet loss or reordering makes use of the - * reassembly queue. - * - * The criteria to step up the receive buffer one notch are: - * 1. Application has not set receive buffer size with - * SO_RCVBUF. Setting SO_RCVBUF clears SB_AUTOSIZE. - * 2. the number of bytes received during the time it takes - * one timestamp to be reflected back to us (the RTT); - * 3. received bytes per RTT is within seven eighth of the - * current socket buffer size; - * 4. receive buffer size has not hit maximal automatic size; - * - * This algorithm does one step per RTT at most and only if - * we receive a bulk stream w/o packet losses or reorderings. - * Shrinking the buffer during idle times is not necessary as - * it doesn't consume any memory when idle. - * - * TODO: Only step up if the application is actually serving - * the buffer to better manage the socket buffer resources. - */ - if (V_tcp_do_autorcvbuf && - (to->to_flags & TOF_TS) && - to->to_tsecr && - (so->so_rcv.sb_flags & SB_AUTOSIZE)) { - if (TSTMP_GT(to->to_tsecr, tp->rfbuf_ts) && - to->to_tsecr - tp->rfbuf_ts < hz) { - if (tp->rfbuf_cnt > - (so->so_rcv.sb_hiwat / 8 * 7) && - so->so_rcv.sb_hiwat < - V_tcp_autorcvbuf_max) { - newsize = - min(so->so_rcv.sb_hiwat + - V_tcp_autorcvbuf_inc, - V_tcp_autorcvbuf_max); - } - /* Start over with next RTT. */ - tp->rfbuf_ts = 0; - tp->rfbuf_cnt = 0; - } else - tp->rfbuf_cnt += tlen; /* add up */ - } + + newsize = tcp_autorcvbuf(m, th, so, tp, tlen); /* Add data to socket buffer. */ SOCKBUF_LOCK(&so->so_rcv); @@ -526,10 +472,6 @@ tcp_do_slowpath(struct mbuf *m, struct tcphdr *th, struct socket *so, win = 0; tp->rcv_wnd = imax(win, (int)(tp->rcv_adv - tp->rcv_nxt)); - /* Reset receive buffer auto scaling when not in bulk receive mode. */ - tp->rfbuf_ts = 0; - tp->rfbuf_cnt = 0; - switch (tp->t_state) { /* diff --git a/freebsd/netinet/tcp_var.h b/freebsd/netinet/tcp_var.h index abfa21ab2..1c2dd0597 100644 --- a/freebsd/netinet/tcp_var.h +++ b/freebsd/netinet/tcp_var.h @@ -779,6 +779,8 @@ void hhook_run_tcp_est_in(struct tcpcb *tp, struct tcphdr *th, struct tcpopt *to); int tcp_input(struct mbuf **, int *, int); +int tcp_autorcvbuf(struct mbuf *, struct tcphdr *, struct socket *, + struct tcpcb *, int); void tcp_do_segment(struct mbuf *, struct tcphdr *, struct socket *, struct tcpcb *, int, int, uint8_t, int);