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From: Andy Furniss <lists@andyfurniss.entadsl.com>
To: Jesper Dangaard Brouer <hawk@diku.dk>
Cc: Stephen Hemminger <stephen.hemminger@vyatta.com>,
	netdev <netdev@vger.kernel.org>,
	"David S. Miller" <davem@davemloft.net>,
	Patrick McHardy <kaber@trash.net>
Subject: Re: [PATCH 2/7] ATM cell alignment.
Date: Sun, 13 Apr 2008 12:24:41 +0100	[thread overview]
Message-ID: <4801ED79.5090502@andyfurniss.entadsl.com> (raw)
In-Reply-To: <Pine.LNX.4.64.0804092259460.21022@ask.diku.dk>

Jesper Dangaard Brouer wrote:

> + The align to ATM cells is used for determining the (ATM) SAR
> + alignment overhead at the ATM layer. (SAR = Segmentation And
> + Reassembly).  This is for example needed when scheduling packet on an
> + ADSL connection.  Note that the extra ATM-AAL overhead is _not_
> + included in this calculation. This overhead is added in the kernel
> + before doing the rate table lookup, as this gives better precision
> + (as the table will always be aligned for 48 bytes).

I see overhead is unsigned short. For me using pppoa/vc mux my overhead 
is IP + 10. I am shaping on eth so skb->len is IP+14 hence I need a 
negative overhead.

Recently built a 2.6.25-rc7 and noticed the cell_align has been added 
and the tables jigged. I am (ab)using this at -5 now. Handy that I only 
need to patch TC rather than kernel and I guess I could use other TCs if 
I needed to shape other not atm ifs.

Russel Stuart's patches handled this case IIRC, has it been lost or have 
I missed something (as usual)?

Andy.

  parent reply	other threads:[~2008-04-13 11:24 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-04-09 20:57 [PATCH 0/7] Final ADSL-optimizer patch series Jesper Dangaard Brouer
2008-04-09 20:59 ` [PATCH 1/7] In police, fix uninitialized "overhead" variable Jesper Dangaard Brouer
2008-04-09 21:01 ` [PATCH 2/7] ATM cell alignment Jesper Dangaard Brouer
2008-04-10 14:35   ` Chas Williams (CONTRACTOR)
2008-04-11  4:53     ` Jesper Dangaard Brouer
2008-04-11 14:18       ` Chas Williams (CONTRACTOR)
2008-04-11 12:51   ` Patrick McHardy
2008-04-11 17:35     ` Jesper Dangaard Brouer
2008-04-13  4:44       ` Patrick McHardy
2008-04-13 11:24   ` Andy Furniss [this message]
2008-04-14  5:59     ` Jesper Dangaard Brouer
2008-04-15 23:41       ` Andy Furniss
2008-04-09 21:02 ` [PATCH 3/7] Parsing linklayer types Jesper Dangaard Brouer
2008-04-09 21:03 ` [PATCH 4/7] Add linklayer parameter to filter action police Jesper Dangaard Brouer
2008-04-09 21:04 ` [PATCH 5/7] Add linklayer parameter to CBQ Jesper Dangaard Brouer
2008-04-09 21:06 ` [PATCH 6/7] Add linklayer parameter to HTB Jesper Dangaard Brouer
2008-04-09 21:07 ` [PATCH 7/7] Add linklayer parameter to TBF Jesper Dangaard Brouer
2008-04-14  5:40 ` [PATCH 0/7] Final ADSL-optimizer patch series David Miller
2008-04-17 17:10 ` Stephen Hemminger

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