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Re: V2.4 policy router operates faster/better than V2.6

To: netdev@xxxxxxxxxxx
Subject: Re: V2.4 policy router operates faster/better than V2.6
From: "Jeremy M. Guthrie" <jeremy.guthrie@xxxxxxxxxx>
Date: Thu, 6 Jan 2005 14:55:50 -0600
Cc: Robert Olsson <Robert.Olsson@xxxxxxxxxxx>, Stephen Hemminger <shemminger@xxxxxxxx>
In-reply-to: <16861.40858.80960.794144@robur.slu.se>
Organization: Berbee Information Networks
References: <200501031455.26980.jeremy.guthrie@berbee.com> <200501061335.55104.jeremy.guthrie@berbee.com> <16861.40858.80960.794144@robur.slu.se>
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Forgot the attachment.  


On Thursday 06 January 2005 02:29 pm, Robert Olsson wrote:
> Jeremy M. Guthrie writes:
>  > >  You only use CPU0 for packet processing. Also it seems you use  the
>  > > non-NAPI version of e1000.
>  >
>  > The E1000 driver is the stock driver in 2.4.28.
>
>  There is a kernel config option.  Use Rx Polling (NAPI)
>
>  > eth2 is TX only.  We don't receive anything on it.  This system should
>  > only ever RX on eth3 and TX on eth2 as part of its function.
>
>  Ok! So unidirectional traffic and CPU0 processes all skb's and passes them
>  over to CPU1 which touches and frees them. You could try some other
>  affinity setting later on but there are so many options depending what
>  we want do. If we just want to compare 2.4/2.6 we can start out simple
>  with setting affinity so only one CPU. Which is almost what you got.
>  We reach all the complicated problems immediately... Now we pass skb's
>  between the CPU's which release cache bouncing and makes slab rebalance
> it's pools. So using just one CPU is probably better... If we had incoming
> pkts on eth2 eventually we could have had any use for CPU1.
>
>  Install NAPI-driver, set affinity so eth2/eth3 uses same CPU to start
> with.
>
>  The stats info you sent was almost impossible to read. See if you can get
>  only the rtstats.
>
>       --ro

-- 

--------------------------------------------------
Jeremy M. Guthrie        jeremy.guthrie@xxxxxxxxxx
Senior Network Engineer        Phone: 608-298-1061
Berbee                           Fax: 608-288-3007
5520 Research Park Drive         NOC: 608-298-1102
Madison, WI 53711

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