| Message ID | 20190913232332.44036-2-tph@fb.com |
|---|---|
| State | Accepted |
| Delegated to: | David Miller |
| Headers | show |
| Series | [v5,1/2] tcp: Add TCP_INFO counter for packets received out-of-order | expand |
On Fri, Sep 13, 2019 at 4:23 PM Thomas Higdon <tph@fb.com> wrote: > > Neal Cardwell mentioned that snd_wnd would be useful for diagnosing TCP > performance problems -- > > (1) Usually when we're diagnosing TCP performance problems, we do so > > from the sender, since the sender makes most of the > > performance-critical decisions (cwnd, pacing, TSO size, TSQ, etc). > > From the sender-side the thing that would be most useful is to see > > tp->snd_wnd, the receive window that the receiver has advertised to > > the sender. > > This serves the purpose of adding an additional __u32 to avoid the > would-be hole caused by the addition of the tcpi_rcvi_ooopack field. > > Signed-off-by: Thomas Higdon <tph@fb.com> > --- Acked-by: Yuchung Cheng <ycheng@google.com> > changes since v4: > - clarify comment > include/uapi/linux/tcp.h | 4 ++++ > net/ipv4/tcp.c | 1 + > 2 files changed, 5 insertions(+) > > diff --git a/include/uapi/linux/tcp.h b/include/uapi/linux/tcp.h > index 20237987ccc8..81e697978e8b 100644 > --- a/include/uapi/linux/tcp.h > +++ b/include/uapi/linux/tcp.h > @@ -272,6 +272,10 @@ struct tcp_info { > __u32 tcpi_reord_seen; /* reordering events seen */ > > __u32 tcpi_rcv_ooopack; /* Out-of-order packets received */ > + > + __u32 tcpi_snd_wnd; /* peer's advertised receive window after > + * scaling (bytes) > + */ > }; > > /* netlink attributes types for SCM_TIMESTAMPING_OPT_STATS */ > diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c > index 4cf58208270e..79c325a07ba5 100644 > --- a/net/ipv4/tcp.c > +++ b/net/ipv4/tcp.c > @@ -3297,6 +3297,7 @@ void tcp_get_info(struct sock *sk, struct tcp_info *info) > info->tcpi_dsack_dups = tp->dsack_dups; > info->tcpi_reord_seen = tp->reord_seen; > info->tcpi_rcv_ooopack = tp->rcv_ooopack; > + info->tcpi_snd_wnd = tp->snd_wnd; > unlock_sock_fast(sk, slow); > } > EXPORT_SYMBOL_GPL(tcp_get_info); > -- > 2.17.1 >
On Fri, Sep 13, 2019 at 7:23 PM Thomas Higdon <tph@fb.com> wrote: > > Neal Cardwell mentioned that snd_wnd would be useful for diagnosing TCP > performance problems -- > > (1) Usually when we're diagnosing TCP performance problems, we do so > > from the sender, since the sender makes most of the > > performance-critical decisions (cwnd, pacing, TSO size, TSQ, etc). > > From the sender-side the thing that would be most useful is to see > > tp->snd_wnd, the receive window that the receiver has advertised to > > the sender. > > This serves the purpose of adding an additional __u32 to avoid the > would-be hole caused by the addition of the tcpi_rcvi_ooopack field. > > Signed-off-by: Thomas Higdon <tph@fb.com> > --- > changes since v4: > - clarify comment Acked-by: Neal Cardwell <ncardwell@google.com> Thanks! neal
On Sat, Sep 14, 2019 at 11:45 AM Neal Cardwell <ncardwell@google.com> wrote: > > On Fri, Sep 13, 2019 at 7:23 PM Thomas Higdon <tph@fb.com> wrote: > > > > Neal Cardwell mentioned that snd_wnd would be useful for diagnosing TCP > > performance problems -- > > > (1) Usually when we're diagnosing TCP performance problems, we do so > > > from the sender, since the sender makes most of the > > > performance-critical decisions (cwnd, pacing, TSO size, TSQ, etc). > > > From the sender-side the thing that would be most useful is to see > > > tp->snd_wnd, the receive window that the receiver has advertised to > > > the sender. > > > > This serves the purpose of adding an additional __u32 to avoid the > > would-be hole caused by the addition of the tcpi_rcvi_ooopack field. > > > > Signed-off-by: Thomas Higdon <tph@fb.com> > > --- > > changes since v4: > > - clarify comment > > Acked-by: Neal Cardwell <ncardwell@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Thank you for adding the new field!
From: Thomas Higdon <tph@fb.com> Date: Fri, 13 Sep 2019 23:23:35 +0000 > Neal Cardwell mentioned that snd_wnd would be useful for diagnosing TCP > performance problems -- >> (1) Usually when we're diagnosing TCP performance problems, we do so >> from the sender, since the sender makes most of the >> performance-critical decisions (cwnd, pacing, TSO size, TSQ, etc). >> From the sender-side the thing that would be most useful is to see >> tp->snd_wnd, the receive window that the receiver has advertised to >> the sender. > > This serves the purpose of adding an additional __u32 to avoid the > would-be hole caused by the addition of the tcpi_rcvi_ooopack field. > > Signed-off-by: Thomas Higdon <tph@fb.com> Applied.
diff --git a/include/uapi/linux/tcp.h b/include/uapi/linux/tcp.h index 20237987ccc8..81e697978e8b 100644 --- a/include/uapi/linux/tcp.h +++ b/include/uapi/linux/tcp.h @@ -272,6 +272,10 @@ struct tcp_info { __u32 tcpi_reord_seen; /* reordering events seen */ __u32 tcpi_rcv_ooopack; /* Out-of-order packets received */ + + __u32 tcpi_snd_wnd; /* peer's advertised receive window after + * scaling (bytes) + */ }; /* netlink attributes types for SCM_TIMESTAMPING_OPT_STATS */ diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 4cf58208270e..79c325a07ba5 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -3297,6 +3297,7 @@ void tcp_get_info(struct sock *sk, struct tcp_info *info) info->tcpi_dsack_dups = tp->dsack_dups; info->tcpi_reord_seen = tp->reord_seen; info->tcpi_rcv_ooopack = tp->rcv_ooopack; + info->tcpi_snd_wnd = tp->snd_wnd; unlock_sock_fast(sk, slow); } EXPORT_SYMBOL_GPL(tcp_get_info);