diff options
| author |   Florian Westphal <fw@strlen.de> | 2014-02-25 14:34:32 +0100 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2014-02-26 15:23:30 -0500 |
| commit | 8e165e20348b53583f6c6cb45865b89209f4aa13 (patch) | |
| tree | 26eab521fe1c2ac3aca539d832d747f2c42bc930 /net/ipv4/tcp_output.c | |
| parent | net: order MPLS ethertypes numerically (diff) | |
| download | linux-dev-8e165e20348b53583f6c6cb45865b89209f4aa13.tar.xz linux-dev-8e165e20348b53583f6c6cb45865b89209f4aa13.zip | |
net: tcp: add mib counters to track zero window transitions
Three counters are added:
- one to track when we went from non-zero to zero window
- one to track the reverse
- one counter incremented when we want to announce zero window,
but can't because we would shrink current window.
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_output.c')
| -rw-r--r-- | net/ipv4/tcp_output.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 21e8a9f33287..c5eadec001c1 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -269,6 +269,7 @@ EXPORT_SYMBOL(tcp_select_initial_window); static u16 tcp_select_window(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); + u32 old_win = tp->rcv_wnd; u32 cur_win = tcp_receive_window(tp); u32 new_win = __tcp_select_window(sk); @@ -281,6 +282,9 @@ static u16 tcp_select_window(struct sock *sk) * * Relax Will Robinson. */ + if (new_win == 0) + NET_INC_STATS(sock_net(sk), + LINUX_MIB_TCPWANTZEROWINDOWADV); new_win = ALIGN(cur_win, 1 << tp->rx_opt.rcv_wscale); } tp->rcv_wnd = new_win; @@ -298,8 +302,14 @@ static u16 tcp_select_window(struct sock *sk) new_win >>= tp->rx_opt.rcv_wscale; /* If we advertise zero window, disable fast path. */ - if (new_win == 0) + if (new_win == 0) { tp->pred_flags = 0; + if (old_win) + NET_INC_STATS(sock_net(sk), + LINUX_MIB_TCPTOZEROWINDOWADV); + } else if (old_win == 0) { + NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPFROMZEROWINDOWADV); + } return new_win; } |