* [PATCH v2 -next] net: tcp: add mib counters to track zero window transitions
@ 2014-02-25 13:34 Florian Westphal
2014-02-26 5:07 ` Eric Dumazet
2014-02-26 20:24 ` David Miller
0 siblings, 2 replies; 3+ messages in thread
From: Florian Westphal @ 2014-02-25 13:34 UTC (permalink / raw)
To: netdev; +Cc: Florian Westphal
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>
---
Changes in v2:
- use NET_INC_STATS, not _BH; can be called from both bh and process context (pointed out by Hannes)
- rename LINUX_MIB_TCPWANTZEROWINDOW to LINUX_MIB_TCPWANTZEROWINDOWADV for consistency
include/uapi/linux/snmp.h | 3 +++
net/ipv4/proc.c | 3 +++
net/ipv4/tcp_output.c | 12 +++++++++++-
3 files changed, 17 insertions(+), 1 deletion(-)
diff --git a/include/uapi/linux/snmp.h b/include/uapi/linux/snmp.h
index bbaba22..8d64a7e 100644
--- a/include/uapi/linux/snmp.h
+++ b/include/uapi/linux/snmp.h
@@ -259,6 +259,9 @@ enum
LINUX_MIB_TCPSPURIOUS_RTX_HOSTQUEUES, /* TCPSpuriousRtxHostQueues */
LINUX_MIB_BUSYPOLLRXPACKETS, /* BusyPollRxPackets */
LINUX_MIB_TCPAUTOCORKING, /* TCPAutoCorking */
+ LINUX_MIB_TCPFROMZEROWINDOWADV, /* TCPFromZeroWindowAdv */
+ LINUX_MIB_TCPTOZEROWINDOWADV, /* TCPToZeroWindowAdv */
+ LINUX_MIB_TCPWANTZEROWINDOWADV, /* TCPWantZeroWindowAdv */
__LINUX_MIB_MAX
};
diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c
index a6c8a80..99d2e9b 100644
--- a/net/ipv4/proc.c
+++ b/net/ipv4/proc.c
@@ -280,6 +280,9 @@ static const struct snmp_mib snmp4_net_list[] = {
SNMP_MIB_ITEM("TCPSpuriousRtxHostQueues", LINUX_MIB_TCPSPURIOUS_RTX_HOSTQUEUES),
SNMP_MIB_ITEM("BusyPollRxPackets", LINUX_MIB_BUSYPOLLRXPACKETS),
SNMP_MIB_ITEM("TCPAutoCorking", LINUX_MIB_TCPAUTOCORKING),
+ SNMP_MIB_ITEM("TCPFromZeroWindowAdv", LINUX_MIB_TCPFROMZEROWINDOWADV),
+ SNMP_MIB_ITEM("TCPToZeroWindowAdv", LINUX_MIB_TCPTOZEROWINDOWADV),
+ SNMP_MIB_ITEM("TCPWantZeroWindowAdv", LINUX_MIB_TCPWANTZEROWINDOWADV),
SNMP_MIB_SENTINEL
};
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 21e8a9f..c5eadec 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;
}
--
1.8.1.5
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v2 -next] net: tcp: add mib counters to track zero window transitions
2014-02-25 13:34 [PATCH v2 -next] net: tcp: add mib counters to track zero window transitions Florian Westphal
@ 2014-02-26 5:07 ` Eric Dumazet
2014-02-26 20:24 ` David Miller
1 sibling, 0 replies; 3+ messages in thread
From: Eric Dumazet @ 2014-02-26 5:07 UTC (permalink / raw)
To: Florian Westphal; +Cc: netdev
On Tue, 2014-02-25 at 14:34 +0100, Florian Westphal wrote:
> 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>
> ---
> Changes in v2:
> - use NET_INC_STATS, not _BH; can be called from both bh and process context (pointed out by Hannes)
> - rename LINUX_MIB_TCPWANTZEROWINDOW to LINUX_MIB_TCPWANTZEROWINDOWADV for consistency
Thanks Florian
Acked-by: Eric Dumazet <edumazet@google.com>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v2 -next] net: tcp: add mib counters to track zero window transitions
2014-02-25 13:34 [PATCH v2 -next] net: tcp: add mib counters to track zero window transitions Florian Westphal
2014-02-26 5:07 ` Eric Dumazet
@ 2014-02-26 20:24 ` David Miller
1 sibling, 0 replies; 3+ messages in thread
From: David Miller @ 2014-02-26 20:24 UTC (permalink / raw)
To: fw; +Cc: netdev
From: Florian Westphal <fw@strlen.de>
Date: Tue, 25 Feb 2014 14:34:32 +0100
> 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>
Applied, thanks everyone.
^ permalink raw reply [flat|nested] 3+ messages in thread
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