From owner-freebsd-net@FreeBSD.ORG  Sun Dec 11 13:48:09 2005
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Date: Sun, 11 Dec 2005 13:48:05 +0000
From: Brian Candler <B.Candler@pobox.com>
To: kamal kc <kamal_ckk@yahoo.com>
Message-ID: <20051211134805.GB98105@uk.tiscali.com>
References: <20051211112650.67553.qmail@web35715.mail.mud.yahoo.com>
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Cc: freebsd <freebsd-net@freebsd.org>
Subject: Re: high interrupts by network interfaces
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On Sun, Dec 11, 2005 at 03:26:50AM -0800, kamal kc wrote:
> i modified the bridge.c file and added a routine to
> compress/decompress 
> ip packet. i put my code in bdg_forward(). And ran the
> pc in bridge mode.
> 
> The modified kernel is deployed in network where the
> datarate is 
> about 4 to 6 Mbps. One thing to be noted is that the
> pc receives 
> continues data at 4 to 6 Mbps rather than sudden burst
> at intervals.
> 
> Now the problem is, I am getting very high interrupts
> from the network 
> interfaces. the cpu utilization by the interrupts is
> high due to which there
> is latency added to the packets forwarded by the pc.
> The pc attempts to 
> compress/decompress all tcp packets.

Suggestion: start with a standard kernel, without your custom modifications.

If unmodified bridging works, and you get the high interrupt level, then you
have found a problem with in FreeBSD.

If unmodified bridging works, but interrupts are at a normal level, then you
have a found a problem with your own code.