* [Bridge] [PATCH] (6/6) bridge: receive path optimization
@ 2005-05-26 18:04 Stephen Hemminger
2005-05-26 21:46 ` [Bridge] " David S. Miller
0 siblings, 1 reply; 6+ messages in thread
From: Stephen Hemminger @ 2005-05-26 18:04 UTC (permalink / raw)
To: David S. Miller; +Cc: netdev, bridge
This improves the bridge local receive path by avoiding going
through another softirq. The bridge receive path is already being called
from a netif_receive_skb() there is no point in going through another
receiveq round trip.
Recursion is limited because bridge can never be a port of a bridge
so handle_bridge() always returns.
Index: bridge/net/bridge/br_input.c
===================================================================
--- bridge.orig/net/bridge/br_input.c
+++ bridge/net/bridge/br_input.c
@@ -26,7 +26,7 @@ static int br_pass_frame_up_finish(struc
#ifdef CONFIG_NETFILTER_DEBUG
skb->nf_debug = 0;
#endif
- netif_rx(skb);
+ netif_receive_skb(skb);
return 0;
}
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bridge] Re: [PATCH] (6/6) bridge: receive path optimization
2005-05-26 18:04 [Bridge] [PATCH] (6/6) bridge: receive path optimization Stephen Hemminger
@ 2005-05-26 21:46 ` David S. Miller
2005-05-26 22:48 ` Stephen Hemminger
0 siblings, 1 reply; 6+ messages in thread
From: David S. Miller @ 2005-05-26 21:46 UTC (permalink / raw)
To: shemminger; +Cc: netdev, bridge
From: Stephen Hemminger <shemminger@osdl.org>
Date: Thu, 26 May 2005 11:04:25 -0700
> This improves the bridge local receive path by avoiding going
> through another softirq. The bridge receive path is already being called
> from a netif_receive_skb() there is no point in going through another
> receiveq round trip.
>
> Recursion is limited because bridge can never be a port of a bridge
> so handle_bridge() always returns.
I applied all 6 patches, but this one in particular I'd like
to comment on.
Remember all of those bridge netfilter stack usage issues
we have a few months ago? This could edge us back into
those problems again.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [Bridge] Re: [PATCH] (6/6) bridge: receive path optimization
2005-05-26 21:46 ` [Bridge] " David S. Miller
@ 2005-05-26 22:48 ` Stephen Hemminger
2005-05-26 22:54 ` David S. Miller
0 siblings, 1 reply; 6+ messages in thread
From: Stephen Hemminger @ 2005-05-26 22:48 UTC (permalink / raw)
To: David S. Miller; +Cc: netdev, bridge
On Thu, 26 May 2005 14:46:38 -0700 (PDT)
"David S. Miller" <davem@davemloft.net> wrote:
> From: Stephen Hemminger <shemminger@osdl.org>
> Date: Thu, 26 May 2005 11:04:25 -0700
>
> > This improves the bridge local receive path by avoiding going
> > through another softirq. The bridge receive path is already being called
> > from a netif_receive_skb() there is no point in going through another
> > receiveq round trip.
> >
> > Recursion is limited because bridge can never be a port of a bridge
> > so handle_bridge() always returns.
>
> I applied all 6 patches, but this one in particular I'd like
> to comment on.
>
> Remember all of those bridge netfilter stack usage issues
> we have a few months ago? This could edge us back into
> those problems again.
no, because the br_frame_finish is called after the netfilter
decision:
netif_receive_skb
handle_bridge
br_handle_frame
br_handle_frame_finish
br_pass_frame_up
br_pass_frame_up_finish
netif_receive_skb <---- change
(normal receive path)
So the call chain is bounded (ie not related to number of filters)
but slightly longer.
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [Bridge] Re: [PATCH] (6/6) bridge: receive path optimization
2005-05-26 22:48 ` Stephen Hemminger
@ 2005-05-26 22:54 ` David S. Miller
2005-05-27 5:57 ` Atul Sabharwal
0 siblings, 1 reply; 6+ messages in thread
From: David S. Miller @ 2005-05-26 22:54 UTC (permalink / raw)
To: shemminger; +Cc: netdev, bridge
From: Stephen Hemminger <shemminger@osdl.org>
Date: Thu, 26 May 2005 15:48:57 -0700
> So the call chain is bounded (ie not related to number of filters)
> but slightly longer.
You're right, thanks for the explanation Stephen.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [Bridge] Re: [PATCH] (6/6) bridge: receive path optimization
2005-05-26 22:54 ` David S. Miller
@ 2005-05-27 5:57 ` Atul Sabharwal
2005-05-27 15:59 ` Stephen Hemminger
0 siblings, 1 reply; 6+ messages in thread
From: Atul Sabharwal @ 2005-05-27 5:57 UTC (permalink / raw)
To: shemminger, David S. Miller; +Cc: netdev, bridge
I have a question about using the 802.1d driver with a switch. I have a
managed switch
which connects to the Xscale MAC using a Reverse MII interface.
It seems that the 802.1d bridge puts the interface into promiscuous mode and
needs multiple
ethernet devices to work with. Can it work with a single ethernet device
which is connected
to a BCM5338 ( broadcomm 8 port switch chip ).
I understand that I would have to change the STP configuration component to
write to the
broadcomm chip.
The chip supports direct memory mapped I/O of BPDU's using polled
xmite/recieve using
a SPI interface. Since I use a soft SPI stack, I cannot go faster than
2MHz. Besides this
is a serial interface.
Suggestion, comments on both choices are highly appreciated. I am working
in a custom
enviornment with main objective of detecting loops in a cascade of switches.
The physical
interconnect of the switches could be linear, tree, star or graph topology.
Also, the spanning tree needs to reconverge when switches are
connected/disconnected.
Since there are no interrupts from the BCM5338, most of the implementation
would be
based of polling. Maybe, a forwarding delay of 5s should work as this is a
LAN environment.
--
Atul
Linux Engineer
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [Bridge] Re: [PATCH] (6/6) bridge: receive path optimization
2005-05-27 5:57 ` Atul Sabharwal
@ 2005-05-27 15:59 ` Stephen Hemminger
0 siblings, 0 replies; 6+ messages in thread
From: Stephen Hemminger @ 2005-05-27 15:59 UTC (permalink / raw)
To: Atul Sabharwal; +Cc: netdev, bridge, David S. Miller
On Thu, 26 May 2005 22:57:05 -0700
"Atul Sabharwal" <iamatul@comcast.net> wrote:
> I have a question about using the 802.1d driver with a switch. I have a
> managed switch
> which connects to the Xscale MAC using a Reverse MII interface.
>
> It seems that the 802.1d bridge puts the interface into promiscuous mode and
> needs multiple
> ethernet devices to work with. Can it work with a single ethernet device
> which is connected
> to a BCM5338 ( broadcomm 8 port switch chip ).
Why? what would you gain?
> I understand that I would have to change the STP configuration component to
> write to the
> broadcomm chip.
You would be better off writing a different driver, the amount of shared
logic would be less than the per hardware logic.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2005-05-27 15:59 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
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2005-05-26 18:04 [Bridge] [PATCH] (6/6) bridge: receive path optimization Stephen Hemminger
2005-05-26 21:46 ` [Bridge] " David S. Miller
2005-05-26 22:48 ` Stephen Hemminger
2005-05-26 22:54 ` David S. Miller
2005-05-27 5:57 ` Atul Sabharwal
2005-05-27 15:59 ` Stephen Hemminger
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