[Click] Quick question

[Eddie Kohler]

Hi Ravi,

The "Expensive Packet::push" message can be safely ignored.  It is 
telling you that in order to add the IP header (introduced by IPEncap), 
the configuration had to make a packet copy.  (The reason is that there 
wasn't enough "free space" to fit an IP header.)  The packet copy can 
have performance consequences, but at user level it's not worth 
worrying about.  If you want to turn off the message, edit 
lib/packet.cc.

Eddie


On Dec 19, 2004, at 1:15 PM, Ravi Bhagavathula wrote:

> Hi,
>
> I am a newbie to CLICK so this question might sound very primitive. I
> modified one of the examples to say
>
> FromDevice(eth0) -> IPEncap(4, 1.1.1.1, 2.2.2.2)
> 			-> Print(IP_Encapsulated_packet)
> 			-> StripIPHeader()
> 			-> Print(Original_Ethernet_Frame)
> 			-> Strip(14)
> 			-> Print(Original_IP_packet)
> 			-> Discard
>
> When I run this, I do get an output which prints the 
> IP_encapsulated_packet,
> the Original_Ethernet_Frame and the Original_IP_packet. But I also get
> something to the tune of "Expensive Packet::push; have 2 wanted 20".
>
> Could anyone explain to me the significance of this message. I am 
> currently
> operating in the user-land with no linux kernel components.
>
> Thanks in advance.
>
> Ravi Bhagavathula, PhD
> 324 Wallace Hall
> Electrical and Computer Engg. Dept.
> Wichita State University,
> Wichita, KS 67260-0044
> Telephone: (316) 978-3494
> Fax: (316) 978-5408
>
>
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